From b95fb6e2bfc425f9d7d8e505446f3f80d7fdb0b2 Mon Sep 17 00:00:00 2001
From: Tor Hovland <55164+torhovland@users.noreply.github.com>
Date: Fri, 31 May 2024 09:28:31 +0200
Subject: [PATCH 1/4] refactor: cargo_generate_lockfile -> cargo_update.

---
 .../{cargo_generate_lockfile.rs => cargo_update.rs}    |  0
 src/cargo/ops/mod.rs                                   | 10 +++++-----
 triagebot.toml                                         |  4 ++--
 3 files changed, 7 insertions(+), 7 deletions(-)
 rename src/cargo/ops/{cargo_generate_lockfile.rs => cargo_update.rs} (100%)

diff --git a/src/cargo/ops/cargo_generate_lockfile.rs b/src/cargo/ops/cargo_update.rs
similarity index 100%
rename from src/cargo/ops/cargo_generate_lockfile.rs
rename to src/cargo/ops/cargo_update.rs
diff --git a/src/cargo/ops/mod.rs b/src/cargo/ops/mod.rs
index 3b4c74c8922..88b422e5b30 100644
--- a/src/cargo/ops/mod.rs
+++ b/src/cargo/ops/mod.rs
@@ -7,10 +7,6 @@ pub use self::cargo_compile::{
 pub use self::cargo_compile::{CompileFilter, FilterRule, LibRule, Packages};
 pub use self::cargo_doc::{doc, DocOptions, OutputFormat};
 pub use self::cargo_fetch::{fetch, FetchOptions};
-pub use self::cargo_generate_lockfile::generate_lockfile;
-pub use self::cargo_generate_lockfile::print_lockfile_changes;
-pub use self::cargo_generate_lockfile::update_lockfile;
-pub use self::cargo_generate_lockfile::UpdateOptions;
 pub use self::cargo_install::{install, install_list};
 pub use self::cargo_new::{init, new, NewOptions, NewProjectKind, VersionControl};
 pub use self::cargo_output_metadata::{output_metadata, ExportInfo, OutputMetadataOptions};
@@ -20,6 +16,10 @@ pub use self::cargo_read_manifest::{read_package, read_packages};
 pub use self::cargo_run::run;
 pub use self::cargo_test::{run_benches, run_tests, TestOptions};
 pub use self::cargo_uninstall::uninstall;
+pub use self::cargo_update::generate_lockfile;
+pub use self::cargo_update::print_lockfile_changes;
+pub use self::cargo_update::update_lockfile;
+pub use self::cargo_update::UpdateOptions;
 pub use self::fix::{fix, fix_exec_rustc, fix_get_proxy_lock_addr, FixOptions};
 pub use self::lockfile::{load_pkg_lockfile, resolve_to_string, write_pkg_lockfile};
 pub use self::registry::modify_owners;
@@ -44,7 +44,6 @@ pub(crate) mod cargo_compile;
 pub mod cargo_config;
 mod cargo_doc;
 mod cargo_fetch;
-mod cargo_generate_lockfile;
 mod cargo_install;
 mod cargo_new;
 mod cargo_output_metadata;
@@ -55,6 +54,7 @@ pub mod cargo_remove;
 mod cargo_run;
 mod cargo_test;
 mod cargo_uninstall;
+mod cargo_update;
 mod common_for_install_and_uninstall;
 mod fix;
 pub(crate) mod lockfile;
diff --git a/triagebot.toml b/triagebot.toml
index b659dee749d..609d7683081 100644
--- a/triagebot.toml
+++ b/triagebot.toml
@@ -265,7 +265,7 @@ trigger_files = [
 ]
 
 [autolabel."Command-generate-lockfile"]
-trigger_files = ["src/bin/cargo/commands/generate_lockfile.rs", "src/cargo/ops/cargo_generate_lockfile.rs"]
+trigger_files = ["src/bin/cargo/commands/generate_lockfile.rs"]
 
 [autolabel."Command-git-checkout"]
 trigger_files = ["src/bin/cargo/commands/git_checkout.rs"]
@@ -334,7 +334,7 @@ trigger_files = ["src/bin/cargo/commands/tree.rs", "src/cargo/ops/tree/"]
 trigger_files = ["src/bin/cargo/commands/uninstall.rs", "src/cargo/ops/cargo_uninstall.rs"]
 
 [autolabel."Command-update"]
-trigger_files = ["src/bin/cargo/commands/update.rs"]
+trigger_files = ["src/bin/cargo/commands/update.rs", "src/cargo/ops/cargo_update.rs"]
 
 [autolabel."Command-vendor"]
 trigger_files = ["src/bin/cargo/commands/vendor.rs", "src/cargo/ops/vendor.rs"]

From b902398b020054c87529ca4222a0a88b62d5efd4 Mon Sep 17 00:00:00 2001
From: Tor Hovland <55164+torhovland@users.noreply.github.com>
Date: Wed, 5 Jun 2024 17:58:08 +0200
Subject: [PATCH 2/4] Add a dry_run argument to resolve_ws().

---
 benches/benchsuite/benches/resolve.rs   |  4 ++++
 src/bin/cargo/commands/add.rs           |  8 +++-----
 src/bin/cargo/commands/remove.rs        |  4 ++--
 src/cargo/core/compiler/standard_lib.rs |  2 ++
 src/cargo/ops/cargo_clean.rs            | 12 ++++++++++--
 src/cargo/ops/cargo_compile/mod.rs      |  2 ++
 src/cargo/ops/cargo_fetch.rs            |  3 ++-
 src/cargo/ops/cargo_install.rs          |  3 ++-
 src/cargo/ops/cargo_output_metadata.rs  |  2 ++
 src/cargo/ops/cargo_package.rs          |  3 ++-
 src/cargo/ops/fix.rs                    |  2 ++
 src/cargo/ops/resolve.rs                | 14 ++++++++++----
 src/cargo/ops/tree/mod.rs               |  2 ++
 src/cargo/ops/vendor.rs                 |  5 +++--
 14 files changed, 48 insertions(+), 18 deletions(-)

diff --git a/benches/benchsuite/benches/resolve.rs b/benches/benchsuite/benches/resolve.rs
index 89d0212e378..d798dd6d62b 100644
--- a/benches/benchsuite/benches/resolve.rs
+++ b/benches/benchsuite/benches/resolve.rs
@@ -33,6 +33,7 @@ fn do_resolve<'gctx>(gctx: &'gctx GlobalContext, ws_root: &Path) -> ResolveInfo<
     let force_all_targets = ForceAllTargets::No;
     // Do an initial run to download anything necessary so that it does
     // not confuse criterion's warmup.
+    let dry_run = false;
     let ws_resolve = cargo::ops::resolve_ws_with_opts(
         &ws,
         &mut target_data,
@@ -41,6 +42,7 @@ fn do_resolve<'gctx>(gctx: &'gctx GlobalContext, ws_root: &Path) -> ResolveInfo<
         &specs,
         has_dev_units,
         force_all_targets,
+        dry_run,
     )
     .unwrap();
     ResolveInfo {
@@ -71,6 +73,7 @@ fn resolve_ws(c: &mut Criterion) {
         // iterator once, and we don't want to call `do_resolve` in every
         // "step", since that would just be some useless work.
         let mut lazy_info = None;
+        let dry_run = false;
         group.bench_function(&ws_name, |b| {
             let ResolveInfo {
                 ws,
@@ -91,6 +94,7 @@ fn resolve_ws(c: &mut Criterion) {
                     specs,
                     *has_dev_units,
                     *force_all_targets,
+                    dry_run,
                 )
                 .unwrap();
             })
diff --git a/src/bin/cargo/commands/add.rs b/src/bin/cargo/commands/add.rs
index 9c67eb8343c..30956b00479 100644
--- a/src/bin/cargo/commands/add.rs
+++ b/src/bin/cargo/commands/add.rs
@@ -214,11 +214,9 @@ pub fn exec(gctx: &mut GlobalContext, args: &ArgMatches) -> CliResult {
     };
     add(&ws, &options)?;
 
-    if !dry_run {
-        // Reload the workspace since we've changed dependencies
-        let ws = args.workspace(gctx)?;
-        resolve_ws(&ws)?;
-    }
+    // Reload the workspace since we've changed dependencies
+    let ws = args.workspace(gctx)?;
+    resolve_ws(&ws, dry_run)?;
 
     Ok(())
 }
diff --git a/src/bin/cargo/commands/remove.rs b/src/bin/cargo/commands/remove.rs
index 25179487c93..b5695e59937 100644
--- a/src/bin/cargo/commands/remove.rs
+++ b/src/bin/cargo/commands/remove.rs
@@ -121,7 +121,7 @@ pub fn exec(gctx: &mut GlobalContext, args: &ArgMatches) -> CliResult {
             ws.gctx()
                 .shell()
                 .set_verbosity(cargo::core::Verbosity::Quiet);
-            let resolve = resolve_ws(&ws);
+            let resolve = resolve_ws(&ws, dry_run);
             ws.gctx().shell().set_verbosity(verbosity);
             resolve?.1
         };
@@ -129,7 +129,7 @@ pub fn exec(gctx: &mut GlobalContext, args: &ArgMatches) -> CliResult {
         // Attempt to gc unused patches and re-resolve if anything is removed
         if gc_unused_patches(&workspace, &resolve)? {
             let ws = args.workspace(gctx)?;
-            resolve_ws(&ws)?;
+            resolve_ws(&ws, dry_run)?;
         }
     }
     Ok(())
diff --git a/src/cargo/core/compiler/standard_lib.rs b/src/cargo/core/compiler/standard_lib.rs
index 684e4426c04..3e387bdddcc 100644
--- a/src/cargo/core/compiler/standard_lib.rs
+++ b/src/cargo/core/compiler/standard_lib.rs
@@ -149,6 +149,7 @@ pub fn resolve_std<'gctx>(
     let cli_features = CliFeatures::from_command_line(
         &features, /*all_features*/ false, /*uses_default_features*/ false,
     )?;
+    let dry_run = false;
     let resolve = ops::resolve_ws_with_opts(
         &std_ws,
         target_data,
@@ -157,6 +158,7 @@ pub fn resolve_std<'gctx>(
         &specs,
         HasDevUnits::No,
         crate::core::resolver::features::ForceAllTargets::No,
+        dry_run,
     )?;
     Ok((
         resolve.pkg_set,
diff --git a/src/cargo/ops/cargo_clean.rs b/src/cargo/ops/cargo_clean.rs
index 5969bf287eb..5297430b175 100644
--- a/src/cargo/ops/cargo_clean.rs
+++ b/src/cargo/ops/cargo_clean.rs
@@ -77,7 +77,14 @@ pub fn clean(ws: &Workspace<'_>, opts: &CleanOptions<'_>) -> CargoResult<()> {
         if opts.spec.is_empty() {
             clean_ctx.remove_paths(&[target_dir.into_path_unlocked()])?;
         } else {
-            clean_specs(&mut clean_ctx, &ws, &profiles, &opts.targets, &opts.spec)?;
+            clean_specs(
+                &mut clean_ctx,
+                &ws,
+                &profiles,
+                &opts.targets,
+                &opts.spec,
+                opts.dry_run,
+            )?;
         }
     }
 
@@ -91,11 +98,12 @@ fn clean_specs(
     profiles: &Profiles,
     targets: &[String],
     spec: &[String],
+    dry_run: bool,
 ) -> CargoResult<()> {
     // Clean specific packages.
     let requested_kinds = CompileKind::from_requested_targets(clean_ctx.gctx, targets)?;
     let target_data = RustcTargetData::new(ws, &requested_kinds)?;
-    let (pkg_set, resolve) = ops::resolve_ws(ws)?;
+    let (pkg_set, resolve) = ops::resolve_ws(ws, dry_run)?;
     let prof_dir_name = profiles.get_dir_name();
     let host_layout = Layout::new(ws, None, &prof_dir_name)?;
     // Convert requested kinds to a Vec of layouts.
diff --git a/src/cargo/ops/cargo_compile/mod.rs b/src/cargo/ops/cargo_compile/mod.rs
index 68f1df76ba6..0553e5e2d5d 100644
--- a/src/cargo/ops/cargo_compile/mod.rs
+++ b/src/cargo/ops/cargo_compile/mod.rs
@@ -264,6 +264,7 @@ pub fn create_bcx<'a, 'gctx>(
             HasDevUnits::No
         }
     };
+    let dry_run = false;
     let resolve = ops::resolve_ws_with_opts(
         ws,
         &mut target_data,
@@ -272,6 +273,7 @@ pub fn create_bcx<'a, 'gctx>(
         &specs,
         has_dev_units,
         crate::core::resolver::features::ForceAllTargets::No,
+        dry_run,
     )?;
     let WorkspaceResolve {
         mut pkg_set,
diff --git a/src/cargo/ops/cargo_fetch.rs b/src/cargo/ops/cargo_fetch.rs
index 761f171f1f6..37b56438cd6 100644
--- a/src/cargo/ops/cargo_fetch.rs
+++ b/src/cargo/ops/cargo_fetch.rs
@@ -19,7 +19,8 @@ pub fn fetch<'a>(
     options: &FetchOptions<'a>,
 ) -> CargoResult<(Resolve, PackageSet<'a>)> {
     ws.emit_warnings()?;
-    let (mut packages, resolve) = ops::resolve_ws(ws)?;
+    let dry_run = false;
+    let (mut packages, resolve) = ops::resolve_ws(ws, dry_run)?;
 
     let jobs = Some(JobsConfig::Integer(1));
     let keep_going = false;
diff --git a/src/cargo/ops/cargo_install.rs b/src/cargo/ops/cargo_install.rs
index a662e891f38..e4304d74829 100644
--- a/src/cargo/ops/cargo_install.rs
+++ b/src/cargo/ops/cargo_install.rs
@@ -561,7 +561,8 @@ impl<'gctx> InstallablePackage<'gctx> {
         // It would be best if `source` could be passed in here to avoid a
         // duplicate "Updating", but since `source` is taken by value, then it
         // wouldn't be available for `compile_ws`.
-        let (pkg_set, resolve) = ops::resolve_ws(&self.ws)?;
+        let dry_run = false;
+        let (pkg_set, resolve) = ops::resolve_ws(&self.ws, dry_run)?;
         ops::check_yanked(
             self.ws.gctx(),
             &pkg_set,
diff --git a/src/cargo/ops/cargo_output_metadata.rs b/src/cargo/ops/cargo_output_metadata.rs
index 408be75faf3..1aadc05d77a 100644
--- a/src/cargo/ops/cargo_output_metadata.rs
+++ b/src/cargo/ops/cargo_output_metadata.rs
@@ -142,6 +142,7 @@ fn build_resolve_graph(
 
     // Note that even with --filter-platform we end up downloading host dependencies as well,
     // as that is the behavior of download_accessible.
+    let dry_run = false;
     let ws_resolve = ops::resolve_ws_with_opts(
         ws,
         &mut target_data,
@@ -150,6 +151,7 @@ fn build_resolve_graph(
         &specs,
         HasDevUnits::Yes,
         force_all,
+        dry_run,
     )?;
 
     let package_map: BTreeMap<PackageId, Package> = ws_resolve
diff --git a/src/cargo/ops/cargo_package.rs b/src/cargo/ops/cargo_package.rs
index 533852551c2..e105d7012d4 100644
--- a/src/cargo/ops/cargo_package.rs
+++ b/src/cargo/ops/cargo_package.rs
@@ -190,7 +190,8 @@ pub fn package(ws: &Workspace<'_>, opts: &PackageOpts<'_>) -> CargoResult<Option
 
     if ws.root().join("Cargo.lock").exists() {
         // Make sure the Cargo.lock is up-to-date and valid.
-        let _ = ops::resolve_ws(ws)?;
+        let dry_run = false;
+        let _ = ops::resolve_ws(ws, dry_run)?;
         // If Cargo.lock does not exist, it will be generated by `build_lock`
         // below, and will be validated during the verification step.
     }
diff --git a/src/cargo/ops/fix.rs b/src/cargo/ops/fix.rs
index 67738ea6fb7..24dd8b63500 100644
--- a/src/cargo/ops/fix.rs
+++ b/src/cargo/ops/fix.rs
@@ -506,6 +506,7 @@ fn check_resolver_change<'gctx>(
     assert_eq!(ws.resolve_behavior(), ResolveBehavior::V1);
     let specs = opts.compile_opts.spec.to_package_id_specs(ws)?;
     let mut resolve_differences = |has_dev_units| -> CargoResult<(WorkspaceResolve<'_>, DiffMap)> {
+        let dry_run = false;
         let ws_resolve = ops::resolve_ws_with_opts(
             ws,
             target_data,
@@ -514,6 +515,7 @@ fn check_resolver_change<'gctx>(
             &specs,
             has_dev_units,
             crate::core::resolver::features::ForceAllTargets::No,
+            dry_run,
         )?;
 
         let feature_opts = FeatureOpts::new_behavior(ResolveBehavior::V2, has_dev_units);
diff --git a/src/cargo/ops/resolve.rs b/src/cargo/ops/resolve.rs
index 1b54bbc2745..678a1fee1ba 100644
--- a/src/cargo/ops/resolve.rs
+++ b/src/cargo/ops/resolve.rs
@@ -115,9 +115,9 @@ version. This may also occur with an optional dependency that is not enabled.";
 ///
 /// This is a simple interface used by commands like `clean`, `fetch`, and
 /// `package`, which don't specify any options or features.
-pub fn resolve_ws<'a>(ws: &Workspace<'a>) -> CargoResult<(PackageSet<'a>, Resolve)> {
+pub fn resolve_ws<'a>(ws: &Workspace<'a>, dry_run: bool) -> CargoResult<(PackageSet<'a>, Resolve)> {
     let mut registry = PackageRegistry::new(ws.gctx())?;
-    let resolve = resolve_with_registry(ws, &mut registry)?;
+    let resolve = resolve_with_registry(ws, &mut registry, dry_run)?;
     let packages = get_resolved_packages(&resolve, registry)?;
     Ok((packages, resolve))
 }
@@ -140,6 +140,7 @@ pub fn resolve_ws_with_opts<'gctx>(
     specs: &[PackageIdSpec],
     has_dev_units: HasDevUnits,
     force_all_targets: ForceAllTargets,
+    dry_run: bool,
 ) -> CargoResult<WorkspaceResolve<'gctx>> {
     let mut registry = PackageRegistry::new(ws.gctx())?;
     let (resolve, resolved_with_overrides) = if ws.ignore_lock() {
@@ -160,7 +161,7 @@ pub fn resolve_ws_with_opts<'gctx>(
     } else if ws.require_optional_deps() {
         // First, resolve the root_package's *listed* dependencies, as well as
         // downloading and updating all remotes and such.
-        let resolve = resolve_with_registry(ws, &mut registry)?;
+        let resolve = resolve_with_registry(ws, &mut registry, dry_run)?;
         // No need to add patches again, `resolve_with_registry` has done it.
         let add_patches = false;
 
@@ -269,6 +270,7 @@ pub fn resolve_ws_with_opts<'gctx>(
 fn resolve_with_registry<'gctx>(
     ws: &Workspace<'gctx>,
     registry: &mut PackageRegistry<'gctx>,
+    dry_run: bool,
 ) -> CargoResult<Resolve> {
     let prev = ops::load_pkg_lockfile(ws)?;
     let mut resolve = resolve_with_previous(
@@ -283,7 +285,11 @@ fn resolve_with_registry<'gctx>(
     )?;
 
     let print = if !ws.is_ephemeral() && ws.require_optional_deps() {
-        ops::write_pkg_lockfile(ws, &mut resolve)?
+        if !dry_run {
+            ops::write_pkg_lockfile(ws, &mut resolve)?
+        } else {
+            true
+        }
     } else {
         // This mostly represents
         // - `cargo install --locked` and the only change is the package is no longer local but
diff --git a/src/cargo/ops/tree/mod.rs b/src/cargo/ops/tree/mod.rs
index da502da8ba9..0940f0ebfad 100644
--- a/src/cargo/ops/tree/mod.rs
+++ b/src/cargo/ops/tree/mod.rs
@@ -131,6 +131,7 @@ pub fn build_and_print(ws: &Workspace<'_>, opts: &TreeOptions) -> CargoResult<()
     } else {
         ForceAllTargets::No
     };
+    let dry_run = false;
     let ws_resolve = ops::resolve_ws_with_opts(
         ws,
         &mut target_data,
@@ -139,6 +140,7 @@ pub fn build_and_print(ws: &Workspace<'_>, opts: &TreeOptions) -> CargoResult<()
         &specs,
         has_dev,
         force_all,
+        dry_run,
     )?;
 
     let package_map: HashMap<PackageId, &Package> = ws_resolve
diff --git a/src/cargo/ops/vendor.rs b/src/cargo/ops/vendor.rs
index 5c83198f2c7..f319dedce38 100644
--- a/src/cargo/ops/vendor.rs
+++ b/src/cargo/ops/vendor.rs
@@ -80,6 +80,7 @@ fn sync(
     workspaces: &[&Workspace<'_>],
     opts: &VendorOptions<'_>,
 ) -> CargoResult<VendorConfig> {
+    let dry_run = false;
     let canonical_destination = try_canonicalize(opts.destination);
     let canonical_destination = canonical_destination.as_deref().unwrap_or(opts.destination);
     let dest_dir_already_exists = canonical_destination.exists();
@@ -112,7 +113,7 @@ fn sync(
     // crate to work with.
     for ws in workspaces {
         let (packages, resolve) =
-            ops::resolve_ws(ws).with_context(|| "failed to load pkg lockfile")?;
+            ops::resolve_ws(ws, dry_run).with_context(|| "failed to load pkg lockfile")?;
 
         packages
             .get_many(resolve.iter())
@@ -144,7 +145,7 @@ fn sync(
     // tables about them.
     for ws in workspaces {
         let (packages, resolve) =
-            ops::resolve_ws(ws).with_context(|| "failed to load pkg lockfile")?;
+            ops::resolve_ws(ws, dry_run).with_context(|| "failed to load pkg lockfile")?;
 
         packages
             .get_many(resolve.iter())

From c694ff0b44c8510878cc83137fb8a0f40531ec67 Mon Sep 17 00:00:00 2001
From: Tor Hovland <55164+torhovland@users.noreply.github.com>
Date: Fri, 31 May 2024 11:09:15 +0200
Subject: [PATCH 3/4] test: For the upcoming `cargo update --breaking` feature.

---
 tests/testsuite/update.rs | 429 +++++++++++++++++++++++++++++++++++++-
 1 file changed, 427 insertions(+), 2 deletions(-)

diff --git a/tests/testsuite/update.rs b/tests/testsuite/update.rs
index 2e6d8daf6c8..609fc59736f 100644
--- a/tests/testsuite/update.rs
+++ b/tests/testsuite/update.rs
@@ -1,7 +1,9 @@
 //! Tests for the `cargo update` command.
 
-use cargo_test_support::registry::Package;
-use cargo_test_support::{basic_lib_manifest, basic_manifest, git, project};
+use cargo_test_support::compare::assert_e2e;
+use cargo_test_support::registry::{self};
+use cargo_test_support::registry::{Dependency, Package};
+use cargo_test_support::{basic_lib_manifest, basic_manifest, git, project, str};
 
 #[cargo_test]
 fn minor_update_two_places() {
@@ -1637,3 +1639,426 @@ fn update_with_missing_feature() {
         )
         .run();
 }
+
+#[cargo_test]
+fn update_breaking_unstable() {
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+                [package]
+                name  =  "foo"
+                version  =  "0.0.1"
+                edition  =  "2015"
+                authors  =  []
+            "#,
+        )
+        .file("src/lib.rs", "")
+        .build();
+
+    p.cargo("update --breaking")
+        .masquerade_as_nightly_cargo(&["update-breaking"])
+        .with_status(1)
+        .with_stderr_contains("[ERROR] unexpected argument '--breaking' found")
+        .run();
+}
+
+#[cargo_test]
+fn update_breaking_dry_run() {
+    Package::new("incompatible", "1.0.0").publish();
+    Package::new("ws", "1.0.0").publish();
+
+    let root_manifest = r#"
+        # Check if formatting is preserved. Nothing here should change, due to dry-run.
+
+        [workspace]
+        members  =  ["foo"]
+
+        [workspace.dependencies]
+        ws  =  "1.0"  # Preserve formatting
+    "#;
+
+    let crate_manifest = r#"
+        # Check if formatting is preserved. Nothing here should change, due to dry-run.
+
+        [package]
+        name  =  "foo"
+        version  =  "0.0.1"
+        edition  =  "2015"
+        authors  =  []
+
+        [dependencies]
+        incompatible  =  "1.0"  # Preserve formatting
+        ws.workspace  =  true  # Preserve formatting
+    "#;
+
+    let p = project()
+        .file("Cargo.toml", root_manifest)
+        .file("foo/Cargo.toml", crate_manifest)
+        .file("foo/src/lib.rs", "")
+        .build();
+
+    p.cargo("generate-lockfile").run();
+    let lock_file = p.read_file("Cargo.lock");
+
+    Package::new("incompatible", "1.0.1").publish();
+    Package::new("ws", "1.0.1").publish();
+
+    Package::new("incompatible", "2.0.0").publish();
+    Package::new("ws", "2.0.0").publish();
+
+    p.cargo("update --dry-run --breaking")
+        .with_status(1)
+        .with_stderr_contains("[ERROR] unexpected argument '--breaking' found")
+        .run();
+
+    let root_manifest_after = p.read_file("Cargo.toml");
+    assert_e2e().eq(&root_manifest_after, root_manifest);
+
+    let crate_manifest_after = p.read_file("foo/Cargo.toml");
+    assert_e2e().eq(&crate_manifest_after, crate_manifest);
+
+    let lock_file_after = p.read_file("Cargo.lock");
+    assert_e2e().eq(&lock_file_after, lock_file);
+}
+
+#[cargo_test]
+fn update_breaking() {
+    registry::alt_init();
+    Package::new("compatible", "1.0.0").publish();
+    Package::new("incompatible", "1.0.0").publish();
+    Package::new("pinned", "1.0.0").publish();
+    Package::new("less-than", "1.0.0").publish();
+    Package::new("renamed-from", "1.0.0").publish();
+    Package::new("pre-release", "1.0.0").publish();
+    Package::new("yanked", "1.0.0").publish();
+    Package::new("ws", "1.0.0").publish();
+    Package::new("shared", "1.0.0").publish();
+    Package::new("multiple-versions", "1.0.0").publish();
+    Package::new("multiple-versions", "2.0.0").publish();
+    Package::new("alternative-1", "1.0.0")
+        .alternative(true)
+        .publish();
+    Package::new("alternative-2", "1.0.0")
+        .alternative(true)
+        .publish();
+    Package::new("bar", "1.0.0").alternative(true).publish();
+    Package::new("multiple-registries", "1.0.0").publish();
+    Package::new("multiple-registries", "2.0.0")
+        .alternative(true)
+        .publish();
+    Package::new("multiple-source-types", "1.0.0").publish();
+
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+                # Check if formatting is preserved
+
+                [workspace]
+                members  =  ["foo", "bar"]
+
+                [workspace.dependencies]
+                ws  =  "1.0"  # This line gets partially rewritten
+            "#,
+        )
+        .file(
+            "foo/Cargo.toml",
+            r#"
+                # Check if formatting is preserved
+
+                [package]
+                name  =  "foo"
+                version  =  "0.0.1"
+                edition  =  "2015"
+                authors  =  []
+
+                [dependencies]
+                compatible  =  "1.0"  # Comment
+                incompatible  =  "1.0"  # Comment
+                pinned  =  "=1.0"  # Comment
+                less-than  =  "<99.0"  # Comment
+                renamed-to  =  { package  =  "renamed-from", version  =  "1.0" }  # Comment
+                pre-release  =  "1.0"  # Comment
+                yanked  =  "1.0"  # Comment
+                ws.workspace  =  true  # Comment
+                shared  =  "1.0"  # Comment
+                multiple-versions  =  "1.0"  # Comment
+                alternative-1  =  { registry  =  "alternative", version  =  "1.0" }  # Comment
+                multiple-registries  =  "1.0"  # Comment
+                bar  =  { path  =  "../bar", registry  =  "alternative", version  =  "1.0.0" }  # Comment
+                multiple-source-types  =  { path  =  "../multiple-source-types", version  =  "1.0.0" }  # Comment
+
+                [dependencies.alternative-2]  # Comment
+                version  =  "1.0"  # Comment
+                registry  =  "alternative"  # Comment
+            "#,
+        )
+        .file("foo/src/lib.rs", "")
+        .file(
+            "bar/Cargo.toml",
+            r#"
+                [package]
+                name = "bar"
+                version = "1.0.0"
+                edition = "2015"
+                authors = []
+
+                [dependencies]
+                shared = "1.0"
+                multiple-versions = "2.0"
+                multiple-registries  =  { registry  =  "alternative", version  =  "2.0" }  # Comment
+                multiple-source-types  =  "1.0"  # Comment
+            "#,
+        )
+        .file("bar/src/lib.rs", "")
+        .file(
+            "multiple-source-types/Cargo.toml",
+            r#"
+                [package]
+                name = "multiple-source-types"
+                version = "1.0.0"
+                edition = "2015"
+                authors = []
+            "#,
+        )
+        .file("multiple-source-types/src/lib.rs", "")
+        .build();
+
+    p.cargo("generate-lockfile").run();
+
+    Package::new("compatible", "1.0.1").publish();
+    Package::new("incompatible", "1.0.1").publish();
+    Package::new("pinned", "1.0.1").publish();
+    Package::new("less-than", "1.0.1").publish();
+    Package::new("renamed-from", "1.0.1").publish();
+    Package::new("ws", "1.0.1").publish();
+    Package::new("multiple-versions", "1.0.1").publish();
+    Package::new("multiple-versions", "2.0.1").publish();
+    Package::new("alternative-1", "1.0.1")
+        .alternative(true)
+        .publish();
+    Package::new("alternative-2", "1.0.1")
+        .alternative(true)
+        .publish();
+
+    Package::new("incompatible", "2.0.0").publish();
+    Package::new("pinned", "2.0.0").publish();
+    Package::new("less-than", "2.0.0").publish();
+    Package::new("renamed-from", "2.0.0").publish();
+    Package::new("pre-release", "2.0.0-alpha").publish();
+    Package::new("yanked", "2.0.0").yanked(true).publish();
+    Package::new("ws", "2.0.0").publish();
+    Package::new("shared", "2.0.0").publish();
+    Package::new("multiple-versions", "3.0.0").publish();
+    Package::new("alternative-1", "2.0.0")
+        .alternative(true)
+        .publish();
+    Package::new("alternative-2", "2.0.0")
+        .alternative(true)
+        .publish();
+    Package::new("bar", "2.0.0").alternative(true).publish();
+    Package::new("multiple-registries", "2.0.0").publish();
+    Package::new("multiple-registries", "3.0.0")
+        .alternative(true)
+        .publish();
+    Package::new("multiple-source-types", "2.0.0").publish();
+
+    p.cargo("update --breaking")
+        .with_status(1)
+        .with_stderr_contains("[ERROR] unexpected argument '--breaking' found")
+        .run();
+
+    let root_manifest = p.read_file("Cargo.toml");
+    assert_e2e().eq(
+        &root_manifest,
+        str![[r#"
+
+                # Check if formatting is preserved
+
+                [workspace]
+                members  =  ["foo", "bar"]
+
+                [workspace.dependencies]
+                ws  =  "1.0"  # This line gets partially rewritten
+            "#]],
+    );
+
+    let foo_manifest = p.read_file("foo/Cargo.toml");
+
+    assert_e2e().eq(
+        &foo_manifest,
+        str![[r#"
+
+                # Check if formatting is preserved
+
+                [package]
+                name  =  "foo"
+                version  =  "0.0.1"
+                edition  =  "2015"
+                authors  =  []
+
+                [dependencies]
+                compatible  =  "1.0"  # Comment
+                incompatible  =  "1.0"  # Comment
+                pinned  =  "=1.0"  # Comment
+                less-than  =  "<99.0"  # Comment
+                renamed-to  =  { package  =  "renamed-from", version  =  "1.0" }  # Comment
+                pre-release  =  "1.0"  # Comment
+                yanked  =  "1.0"  # Comment
+                ws.workspace  =  true  # Comment
+                shared  =  "1.0"  # Comment
+                multiple-versions  =  "1.0"  # Comment
+                alternative-1  =  { registry  =  "alternative", version  =  "1.0" }  # Comment
+                multiple-registries  =  "1.0"  # Comment
+                bar  =  { path  =  "../bar", registry  =  "alternative", version  =  "1.0.0" }  # Comment
+                multiple-source-types  =  { path  =  "../multiple-source-types", version  =  "1.0.0" }  # Comment
+
+                [dependencies.alternative-2]  # Comment
+                version  =  "1.0"  # Comment
+                registry  =  "alternative"  # Comment
+            "#]],
+    );
+
+    let bar_manifest = p.read_file("bar/Cargo.toml");
+
+    assert_e2e().eq(
+        &bar_manifest,
+        str![[r#"
+
+                [package]
+                name = "bar"
+                version = "1.0.0"
+                edition = "2015"
+                authors = []
+
+                [dependencies]
+                shared = "1.0"
+                multiple-versions = "2.0"
+                multiple-registries  =  { registry  =  "alternative", version  =  "2.0" }  # Comment
+                multiple-source-types  =  "1.0"  # Comment
+            "#]],
+    );
+
+    p.cargo("update")
+        .with_stderr(
+            "\
+[UPDATING] `alternative` index
+[UPDATING] `dummy-registry` index
+[LOCKING] 10 packages to latest compatible versions
+[UPDATING] alternative-1 v1.0.0 (registry `alternative`) -> v1.0.1 (latest: v2.0.0)
+[UPDATING] alternative-2 v1.0.0 (registry `alternative`) -> v1.0.1 (latest: v2.0.0)
+[UPDATING] compatible v1.0.0 -> v1.0.1
+[UPDATING] incompatible v1.0.0 -> v1.0.1 (latest: v2.0.0)
+[UPDATING] less-than v1.0.0 -> v2.0.0
+[REMOVING] multiple-versions v1.0.0
+[REMOVING] multiple-versions v2.0.0
+[ADDING] multiple-versions v1.0.1 (latest: v3.0.0)
+[ADDING] multiple-versions v2.0.1 (latest: v3.0.0)
+[UPDATING] pinned v1.0.0 -> v1.0.1 (latest: v2.0.0)
+[UPDATING] renamed-from v1.0.0 -> v1.0.1 (latest: v2.0.0)
+[UPDATING] ws v1.0.0 -> v1.0.1 (latest: v2.0.0)
+[NOTE] pass `--verbose` to see 4 unchanged dependencies behind latest
+",
+        )
+        .run();
+}
+
+#[cargo_test]
+fn update_breaking_specific_packages() {
+    Package::new("just-foo", "1.0.0")
+        .add_dep(Dependency::new("transitive-compatible", "1.0.0").build())
+        .add_dep(Dependency::new("transitive-incompatible", "1.0.0").build())
+        .publish();
+    Package::new("just-bar", "1.0.0").publish();
+    Package::new("shared", "1.0.0").publish();
+    Package::new("ws", "1.0.0").publish();
+    Package::new("transitive-compatible", "1.0.0").publish();
+    Package::new("transitive-incompatible", "1.0.0").publish();
+
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+            [workspace]
+            members = ["foo", "bar"]
+
+            [workspace.dependencies]
+            ws = "1.0"
+        "#,
+        )
+        .file(
+            "foo/Cargo.toml",
+            r#"
+                [package]
+                name = "foo"
+                version = "0.0.1"
+                edition = "2015"
+                authors = []
+
+                [dependencies]
+                just-foo = "1.0"
+                shared = "1.0"
+                ws.workspace = true
+            "#,
+        )
+        .file("foo/src/lib.rs", "")
+        .file(
+            "bar/Cargo.toml",
+            r#"
+                [package]
+                name = "bar"
+                version = "0.0.1"
+                edition = "2015"
+                authors = []
+
+                [dependencies]
+                just-bar = "1.0"
+                shared = "1.0"
+                ws.workspace = true
+        "#,
+        )
+        .file("bar/src/lib.rs", "")
+        .build();
+
+    p.cargo("generate-lockfile").run();
+
+    Package::new("just-foo", "1.0.1")
+        .add_dep(Dependency::new("transitive-compatible", "1.0.0").build())
+        .add_dep(Dependency::new("transitive-incompatible", "1.0.0").build())
+        .publish();
+    Package::new("just-bar", "1.0.1").publish();
+    Package::new("shared", "1.0.1").publish();
+    Package::new("ws", "1.0.1").publish();
+    Package::new("transitive-compatible", "1.0.1").publish();
+    Package::new("transitive-incompatible", "1.0.1").publish();
+
+    Package::new("just-foo", "2.0.0")
+        // Upgrading just-foo implies accepting an update of transitive-compatible.
+        .add_dep(Dependency::new("transitive-compatible", "1.0.1").build())
+        // Upgrading just-foo implies accepting a major update of transitive-incompatible.
+        .add_dep(Dependency::new("transitive-incompatible", "2.0.0").build())
+        .publish();
+    Package::new("just-bar", "2.0.0").publish();
+    Package::new("shared", "2.0.0").publish();
+    Package::new("ws", "2.0.0").publish();
+    Package::new("transitive-incompatible", "2.0.0").publish();
+
+    p.cargo("update --breaking just-foo shared ws")
+        .with_status(1)
+        .with_stderr_contains("[ERROR] unexpected argument '--breaking' found")
+        .run();
+
+    p.cargo("update just-foo shared ws")
+        .with_stderr(
+            "\
+[UPDATING] `[..]` index
+[LOCKING] 3 packages to latest compatible versions
+[UPDATING] just-foo v1.0.0 -> v1.0.1 (latest: v2.0.0)
+[UPDATING] shared v1.0.0 -> v1.0.1 (latest: v2.0.0)
+[UPDATING] ws v1.0.0 -> v1.0.1 (latest: v2.0.0)
+[NOTE] pass `--verbose` to see 3 unchanged dependencies behind latest
+",
+        )
+        .run();
+}

From 031b410181ed3e20152bbe8b9b3b771995474111 Mon Sep 17 00:00:00 2001
From: Tor Hovland <55164+torhovland@users.noreply.github.com>
Date: Mon, 27 May 2024 12:08:32 +0200
Subject: [PATCH 4/4] feat: Implement `cargo update --breaking`.

---
 crates/cargo-test-support/src/compare.rs      |   1 +
 src/bin/cargo/commands/update.rs              |  30 +-
 src/cargo/core/summary.rs                     |  16 +-
 src/cargo/ops/cargo_update.rs                 | 261 +++++++++++++++++-
 src/cargo/ops/mod.rs                          |   2 +
 src/cargo/util/toml_mut/manifest.rs           |  66 +++--
 src/cargo/util/toml_mut/mod.rs                |   1 +
 src/cargo/util/toml_mut/upgrade.rs            | 219 +++++++++++++++
 src/doc/src/reference/unstable.md             |  20 ++
 .../cargo_update/help/stdout.term.svg         |  44 +--
 tests/testsuite/update.rs                     | 114 +++++---
 11 files changed, 686 insertions(+), 88 deletions(-)
 create mode 100644 src/cargo/util/toml_mut/upgrade.rs

diff --git a/crates/cargo-test-support/src/compare.rs b/crates/cargo-test-support/src/compare.rs
index 53b752621de..a6a9d30e7af 100644
--- a/crates/cargo-test-support/src/compare.rs
+++ b/crates/cargo-test-support/src/compare.rs
@@ -176,6 +176,7 @@ static E2E_LITERAL_REDACTIONS: &[(&str, &str)] = &[
     ("[DIRTY]", "       Dirty"),
     ("[LOCKING]", "     Locking"),
     ("[UPDATING]", "    Updating"),
+    ("[UPGRADING]", "   Upgrading"),
     ("[ADDING]", "      Adding"),
     ("[REMOVING]", "    Removing"),
     ("[REMOVED]", "     Removed"),
diff --git a/src/bin/cargo/commands/update.rs b/src/bin/cargo/commands/update.rs
index fb394e4aa33..3369763d676 100644
--- a/src/bin/cargo/commands/update.rs
+++ b/src/bin/cargo/commands/update.rs
@@ -35,6 +35,13 @@ pub fn cli() -> Command {
                 .value_name("PRECISE")
                 .requires("package-group"),
         )
+        .arg(
+            flag(
+                "breaking",
+                "Upgrade [SPEC] to latest breaking versions, unless pinned (unstable)",
+            )
+            .short('b'),
+        )
         .arg_silent_suggestion()
         .arg(
             flag("workspace", "Only update the workspace packages")
@@ -59,7 +66,8 @@ pub fn exec(gctx: &mut GlobalContext, args: &ArgMatches) -> CliResult {
             gctx.cli_unstable().msrv_policy,
         )?;
     }
-    let ws = args.workspace(gctx)?;
+
+    let mut ws = args.workspace(gctx)?;
 
     if args.is_present_with_zero_values("package") {
         print_available_packages(&ws)?;
@@ -89,6 +97,24 @@ pub fn exec(gctx: &mut GlobalContext, args: &ArgMatches) -> CliResult {
         workspace: args.flag("workspace"),
         gctx,
     };
-    ops::update_lockfile(&ws, &update_opts)?;
+
+    if args.flag("breaking") {
+        gctx.cli_unstable()
+            .fail_if_stable_opt("--breaking", 12425)?;
+
+        let upgrades = ops::upgrade_manifests(&mut ws, &update_opts.to_update)?;
+        ops::resolve_ws(&ws, update_opts.dry_run)?;
+        ops::write_manifest_upgrades(&ws, &upgrades, update_opts.dry_run)?;
+
+        if update_opts.dry_run {
+            update_opts
+                .gctx
+                .shell()
+                .warn("aborting update due to dry run")?;
+        }
+    } else {
+        ops::update_lockfile(&ws, &update_opts)?;
+    }
+
     Ok(())
 }
diff --git a/src/cargo/core/summary.rs b/src/cargo/core/summary.rs
index ec0197cf40d..d7744e24ef7 100644
--- a/src/cargo/core/summary.rs
+++ b/src/cargo/core/summary.rs
@@ -103,15 +103,25 @@ impl Summary {
         Rc::make_mut(&mut self.inner).checksum = Some(cksum);
     }
 
-    pub fn map_dependencies<F>(mut self, f: F) -> Summary
+    pub fn map_dependencies<F>(self, mut f: F) -> Summary
     where
         F: FnMut(Dependency) -> Dependency,
+    {
+        self.try_map_dependencies(|dep| Ok(f(dep))).unwrap()
+    }
+
+    pub fn try_map_dependencies<F>(mut self, f: F) -> CargoResult<Summary>
+    where
+        F: FnMut(Dependency) -> CargoResult<Dependency>,
     {
         {
             let slot = &mut Rc::make_mut(&mut self.inner).dependencies;
-            *slot = mem::take(slot).into_iter().map(f).collect();
+            *slot = mem::take(slot)
+                .into_iter()
+                .map(f)
+                .collect::<CargoResult<_>>()?;
         }
-        self
+        Ok(self)
     }
 
     pub fn map_source(self, to_replace: SourceId, replace_with: SourceId) -> Summary {
diff --git a/src/cargo/ops/cargo_update.rs b/src/cargo/ops/cargo_update.rs
index fc22608e8f2..35902aaad55 100644
--- a/src/cargo/ops/cargo_update.rs
+++ b/src/cargo/ops/cargo_update.rs
@@ -1,3 +1,4 @@
+use crate::core::dependency::Dependency;
 use crate::core::registry::PackageRegistry;
 use crate::core::resolver::features::{CliFeatures, HasDevUnits};
 use crate::core::shell::Verbosity;
@@ -8,11 +9,18 @@ use crate::ops;
 use crate::sources::source::QueryKind;
 use crate::util::cache_lock::CacheLockMode;
 use crate::util::context::GlobalContext;
-use crate::util::style;
-use crate::util::CargoResult;
+use crate::util::toml_mut::dependency::{MaybeWorkspace, Source};
+use crate::util::toml_mut::manifest::LocalManifest;
+use crate::util::toml_mut::upgrade::upgrade_requirement;
+use crate::util::{style, OptVersionReq};
+use crate::util::{CargoResult, VersionExt};
+use itertools::Itertools;
+use semver::{Op, Version, VersionReq};
 use std::cmp::Ordering;
-use std::collections::{BTreeMap, HashSet};
-use tracing::debug;
+use std::collections::{BTreeMap, HashMap, HashSet};
+use tracing::{debug, trace};
+
+pub type UpgradeMap = HashMap<(String, SourceId), Version>;
 
 pub struct UpdateOptions<'a> {
     pub gctx: &'a GlobalContext,
@@ -206,6 +214,251 @@ pub fn print_lockfile_changes(
         print_lockfile_generation(ws, resolve, registry)
     }
 }
+pub fn upgrade_manifests(
+    ws: &mut Workspace<'_>,
+    to_update: &Vec<String>,
+) -> CargoResult<UpgradeMap> {
+    let gctx = ws.gctx();
+    let mut upgrades = HashMap::new();
+    let mut upgrade_messages = HashSet::new();
+
+    // Updates often require a lot of modifications to the registry, so ensure
+    // that we're synchronized against other Cargos.
+    let _lock = gctx.acquire_package_cache_lock(CacheLockMode::DownloadExclusive)?;
+
+    let mut registry = PackageRegistry::new(gctx)?;
+    registry.lock_patches();
+
+    for member in ws.members_mut().sorted() {
+        debug!("upgrading manifest for `{}`", member.name());
+
+        *member.manifest_mut().summary_mut() = member
+            .manifest()
+            .summary()
+            .clone()
+            .try_map_dependencies(|d| {
+                upgrade_dependency(
+                    &gctx,
+                    to_update,
+                    &mut registry,
+                    &mut upgrades,
+                    &mut upgrade_messages,
+                    d,
+                )
+            })?;
+    }
+
+    Ok(upgrades)
+}
+
+fn upgrade_dependency(
+    gctx: &GlobalContext,
+    to_update: &Vec<String>,
+    registry: &mut PackageRegistry<'_>,
+    upgrades: &mut UpgradeMap,
+    upgrade_messages: &mut HashSet<String>,
+    dependency: Dependency,
+) -> CargoResult<Dependency> {
+    let name = dependency.package_name();
+    let renamed_to = dependency.name_in_toml();
+
+    if name != renamed_to {
+        trace!(
+            "skipping dependency renamed from `{}` to `{}`",
+            name,
+            renamed_to
+        );
+        return Ok(dependency);
+    }
+
+    if !to_update.is_empty() && !to_update.contains(&name.to_string()) {
+        trace!("skipping dependency `{}` not selected for upgrading", name);
+        return Ok(dependency);
+    }
+
+    if !dependency.source_id().is_registry() {
+        trace!("skipping non-registry dependency: {}", name);
+        return Ok(dependency);
+    }
+
+    let version_req = dependency.version_req();
+
+    let OptVersionReq::Req(current) = version_req else {
+        trace!(
+            "skipping dependency `{}` without a simple version requirement: {}",
+            name,
+            version_req
+        );
+        return Ok(dependency);
+    };
+
+    let [comparator] = &current.comparators[..] else {
+        trace!(
+            "skipping dependency `{}` with multiple version comparators: {:?}",
+            name,
+            &current.comparators
+        );
+        return Ok(dependency);
+    };
+
+    if comparator.op != Op::Caret {
+        trace!("skipping non-caret dependency `{}`: {}", name, comparator);
+        return Ok(dependency);
+    }
+
+    let query =
+        crate::core::dependency::Dependency::parse(name, None, dependency.source_id().clone())?;
+
+    let possibilities = {
+        loop {
+            match registry.query_vec(&query, QueryKind::Exact) {
+                std::task::Poll::Ready(res) => {
+                    break res?;
+                }
+                std::task::Poll::Pending => registry.block_until_ready()?,
+            }
+        }
+    };
+
+    let latest = if !possibilities.is_empty() {
+        possibilities
+            .iter()
+            .map(|s| s.as_summary())
+            .map(|s| s.version())
+            .filter(|v| !v.is_prerelease())
+            .max()
+    } else {
+        None
+    };
+
+    let Some(latest) = latest else {
+        trace!(
+            "skipping dependency `{}` without any published versions",
+            name
+        );
+        return Ok(dependency);
+    };
+
+    if current.matches(&latest) {
+        trace!(
+            "skipping dependency `{}` without a breaking update available",
+            name
+        );
+        return Ok(dependency);
+    }
+
+    let Some(new_req_string) = upgrade_requirement(&current.to_string(), latest)? else {
+        trace!(
+            "skipping dependency `{}` because the version requirement didn't change",
+            name
+        );
+        return Ok(dependency);
+    };
+
+    let upgrade_message = format!("{} {} -> {}", name, current, new_req_string);
+    trace!(upgrade_message);
+
+    if upgrade_messages.insert(upgrade_message.clone()) {
+        gctx.shell()
+            .status_with_color("Upgrading", &upgrade_message, &style::GOOD)?;
+    }
+
+    upgrades.insert((name.to_string(), dependency.source_id()), latest.clone());
+
+    let req = OptVersionReq::Req(VersionReq::parse(&latest.to_string())?);
+    let mut dep = dependency.clone();
+    dep.set_version_req(req);
+    Ok(dep)
+}
+
+/// Update manifests with upgraded versions, and write to disk. Based on cargo-edit.
+/// Returns true if any file has changed.
+pub fn write_manifest_upgrades(
+    ws: &Workspace<'_>,
+    upgrades: &UpgradeMap,
+    dry_run: bool,
+) -> CargoResult<bool> {
+    if upgrades.is_empty() {
+        return Ok(false);
+    }
+
+    let mut any_file_has_changed = false;
+
+    let manifest_paths = std::iter::once(ws.root_manifest())
+        .chain(ws.members().map(|member| member.manifest_path()))
+        .collect::<Vec<_>>();
+
+    for manifest_path in manifest_paths {
+        trace!(
+            "updating TOML manifest at `{:?}` with upgraded dependencies",
+            manifest_path
+        );
+
+        let crate_root = manifest_path
+            .parent()
+            .expect("manifest path is absolute")
+            .to_owned();
+
+        let mut local_manifest = LocalManifest::try_new(&manifest_path)?;
+        let mut manifest_has_changed = false;
+
+        for dep_table in local_manifest.get_dependency_tables_mut() {
+            for (mut dep_key, dep_item) in dep_table.iter_mut() {
+                let dep_key_str = dep_key.get();
+                let dependency = crate::util::toml_mut::dependency::Dependency::from_toml(
+                    &manifest_path,
+                    dep_key_str,
+                    dep_item,
+                )?;
+
+                let Some(current) = dependency.version() else {
+                    trace!("skipping dependency without a version: {}", dependency.name);
+                    continue;
+                };
+
+                let (MaybeWorkspace::Other(source_id), Some(Source::Registry(source))) =
+                    (dependency.source_id(ws.gctx())?, dependency.source())
+                else {
+                    trace!("skipping non-registry dependency: {}", dependency.name);
+                    continue;
+                };
+
+                let Some(latest) = upgrades.get(&(dependency.name.to_owned(), source_id)) else {
+                    trace!(
+                        "skipping dependency without an upgrade: {}",
+                        dependency.name
+                    );
+                    continue;
+                };
+
+                let Some(new_req_string) = upgrade_requirement(current, latest)? else {
+                    trace!(
+                        "skipping dependency `{}` because the version requirement didn't change",
+                        dependency.name
+                    );
+                    continue;
+                };
+
+                let mut dep = dependency.clone();
+                let mut source = source.clone();
+                source.version = new_req_string;
+                dep.source = Some(Source::Registry(source));
+
+                trace!("upgrading dependency {}", dependency.name);
+                dep.update_toml(&crate_root, &mut dep_key, dep_item);
+                manifest_has_changed = true;
+                any_file_has_changed = true;
+            }
+        }
+
+        if manifest_has_changed && !dry_run {
+            debug!("writing upgraded manifest to {}", manifest_path.display());
+            local_manifest.write()?;
+        }
+    }
+
+    Ok(any_file_has_changed)
+}
 
 fn print_lockfile_generation(
     ws: &Workspace<'_>,
diff --git a/src/cargo/ops/mod.rs b/src/cargo/ops/mod.rs
index 88b422e5b30..49dfaf53fc8 100644
--- a/src/cargo/ops/mod.rs
+++ b/src/cargo/ops/mod.rs
@@ -19,6 +19,8 @@ pub use self::cargo_uninstall::uninstall;
 pub use self::cargo_update::generate_lockfile;
 pub use self::cargo_update::print_lockfile_changes;
 pub use self::cargo_update::update_lockfile;
+pub use self::cargo_update::upgrade_manifests;
+pub use self::cargo_update::write_manifest_upgrades;
 pub use self::cargo_update::UpdateOptions;
 pub use self::fix::{fix, fix_exec_rustc, fix_get_proxy_lock_addr, FixOptions};
 pub use self::lockfile::{load_pkg_lockfile, resolve_to_string, write_pkg_lockfile};
diff --git a/src/cargo/util/toml_mut/manifest.rs b/src/cargo/util/toml_mut/manifest.rs
index 1fbfb9decca..d7ed18440d2 100644
--- a/src/cargo/util/toml_mut/manifest.rs
+++ b/src/cargo/util/toml_mut/manifest.rs
@@ -276,23 +276,6 @@ impl LocalManifest {
 
     /// Write changes back to the file.
     pub fn write(&self) -> CargoResult<()> {
-        if !self.manifest.data.contains_key("package")
-            && !self.manifest.data.contains_key("project")
-        {
-            if self.manifest.data.contains_key("workspace") {
-                anyhow::bail!(
-                    "found virtual manifest at {}, but this command requires running against an \
-                         actual package in this workspace.",
-                    self.path.display()
-                );
-            } else {
-                anyhow::bail!(
-                    "missing expected `package` or `project` fields in {}",
-                    self.path.display()
-                );
-            }
-        }
-
         let s = self.manifest.data.to_string();
         let new_contents_bytes = s.as_bytes();
 
@@ -397,6 +380,55 @@ impl LocalManifest {
         Ok(())
     }
 
+    /// Allow mutating depedencies, wherever they live.
+    /// Copied from cargo-edit.
+    pub fn get_dependency_tables_mut(
+        &mut self,
+    ) -> impl Iterator<Item = &mut dyn toml_edit::TableLike> + '_ {
+        let root = self.data.as_table_mut();
+        root.iter_mut().flat_map(|(k, v)| {
+            if DepTable::KINDS
+                .iter()
+                .any(|dt| dt.kind.kind_table() == k.get())
+            {
+                v.as_table_like_mut().into_iter().collect::<Vec<_>>()
+            } else if k == "workspace" {
+                v.as_table_like_mut()
+                    .unwrap()
+                    .iter_mut()
+                    .filter_map(|(k, v)| {
+                        if k.get() == "dependencies" {
+                            v.as_table_like_mut()
+                        } else {
+                            None
+                        }
+                    })
+                    .collect::<Vec<_>>()
+            } else if k == "target" {
+                v.as_table_like_mut()
+                    .unwrap()
+                    .iter_mut()
+                    .flat_map(|(_, v)| {
+                        v.as_table_like_mut().into_iter().flat_map(|v| {
+                            v.iter_mut().filter_map(|(k, v)| {
+                                if DepTable::KINDS
+                                    .iter()
+                                    .any(|dt| dt.kind.kind_table() == k.get())
+                                {
+                                    v.as_table_like_mut()
+                                } else {
+                                    None
+                                }
+                            })
+                        })
+                    })
+                    .collect::<Vec<_>>()
+            } else {
+                Vec::new()
+            }
+        })
+    }
+
     /// Remove references to `dep_key` if its no longer present.
     pub fn gc_dep(&mut self, dep_key: &str) {
         let explicit_dep_activation = self.is_explicit_dep_activation(dep_key);
diff --git a/src/cargo/util/toml_mut/mod.rs b/src/cargo/util/toml_mut/mod.rs
index cb5d3aaf292..1da707ea192 100644
--- a/src/cargo/util/toml_mut/mod.rs
+++ b/src/cargo/util/toml_mut/mod.rs
@@ -11,6 +11,7 @@
 
 pub mod dependency;
 pub mod manifest;
+pub mod upgrade;
 
 // Based on Iterator::is_sorted from nightly std; remove in favor of that when stabilized.
 pub fn is_sorted(mut it: impl Iterator<Item = impl PartialOrd>) -> bool {
diff --git a/src/cargo/util/toml_mut/upgrade.rs b/src/cargo/util/toml_mut/upgrade.rs
new file mode 100644
index 00000000000..5bf7dacee4b
--- /dev/null
+++ b/src/cargo/util/toml_mut/upgrade.rs
@@ -0,0 +1,219 @@
+use std::fmt::Display;
+
+use crate::CargoResult;
+
+/// Upgrade an existing requirement to a new version.
+/// Copied from cargo-edit.
+pub(crate) fn upgrade_requirement(
+    req: &str,
+    version: &semver::Version,
+) -> CargoResult<Option<String>> {
+    let req_text = req.to_string();
+    let raw_req = semver::VersionReq::parse(&req_text)
+        .expect("semver to generate valid version requirements");
+    if raw_req.comparators.is_empty() {
+        // Empty matches everything, no-change.
+        Ok(None)
+    } else {
+        let comparators: CargoResult<Vec<_>> = raw_req
+            .comparators
+            .into_iter()
+            .map(|p| set_comparator(p, version))
+            .collect();
+        let comparators = comparators?;
+        let new_req = semver::VersionReq { comparators };
+        let mut new_req_text = new_req.to_string();
+        if new_req_text.starts_with('^') && !req.starts_with('^') {
+            new_req_text.remove(0);
+        }
+        // Validate contract
+        #[cfg(debug_assertions)]
+        {
+            assert!(
+                new_req.matches(version),
+                "New req {} is invalid, because {} does not match {}",
+                new_req_text,
+                new_req,
+                version
+            )
+        }
+        if new_req_text == req_text {
+            Ok(None)
+        } else {
+            Ok(Some(new_req_text))
+        }
+    }
+}
+
+fn set_comparator(
+    mut pred: semver::Comparator,
+    version: &semver::Version,
+) -> CargoResult<semver::Comparator> {
+    match pred.op {
+        semver::Op::Wildcard => {
+            pred.major = version.major;
+            if pred.minor.is_some() {
+                pred.minor = Some(version.minor);
+            }
+            if pred.patch.is_some() {
+                pred.patch = Some(version.patch);
+            }
+            Ok(pred)
+        }
+        semver::Op::Exact => Ok(assign_partial_req(version, pred)),
+        semver::Op::Greater | semver::Op::GreaterEq | semver::Op::Less | semver::Op::LessEq => {
+            let user_pred = pred.to_string();
+            Err(unsupported_version_req(user_pred))
+        }
+        semver::Op::Tilde => Ok(assign_partial_req(version, pred)),
+        semver::Op::Caret => Ok(assign_partial_req(version, pred)),
+        _ => {
+            let user_pred = pred.to_string();
+            Err(unsupported_version_req(user_pred))
+        }
+    }
+}
+
+fn assign_partial_req(
+    version: &semver::Version,
+    mut pred: semver::Comparator,
+) -> semver::Comparator {
+    pred.major = version.major;
+    if pred.minor.is_some() {
+        pred.minor = Some(version.minor);
+    }
+    if pred.patch.is_some() {
+        pred.patch = Some(version.patch);
+    }
+    pred.pre = version.pre.clone();
+    pred
+}
+
+fn unsupported_version_req(req: impl Display) -> anyhow::Error {
+    anyhow::format_err!("Support for modifying {} is currently unsupported", req)
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    mod upgrade_requirement {
+        use super::*;
+
+        #[track_caller]
+        fn assert_req_bump<'a, O: Into<Option<&'a str>>>(version: &str, req: &str, expected: O) {
+            let version = semver::Version::parse(version).unwrap();
+            let actual = upgrade_requirement(req, &version).unwrap();
+            let expected = expected.into();
+            assert_eq!(actual.as_deref(), expected);
+        }
+
+        #[test]
+        fn wildcard_major() {
+            assert_req_bump("1.0.0", "*", None);
+        }
+
+        #[test]
+        fn wildcard_minor() {
+            assert_req_bump("1.0.0", "1.*", None);
+            assert_req_bump("1.1.0", "1.*", None);
+            assert_req_bump("2.0.0", "1.*", "2.*");
+        }
+
+        #[test]
+        fn wildcard_patch() {
+            assert_req_bump("1.0.0", "1.0.*", None);
+            assert_req_bump("1.1.0", "1.0.*", "1.1.*");
+            assert_req_bump("1.1.1", "1.0.*", "1.1.*");
+            assert_req_bump("2.0.0", "1.0.*", "2.0.*");
+        }
+
+        #[test]
+        fn caret_major() {
+            assert_req_bump("1.0.0", "1", None);
+            assert_req_bump("1.0.0", "^1", None);
+
+            assert_req_bump("1.1.0", "1", None);
+            assert_req_bump("1.1.0", "^1", None);
+
+            assert_req_bump("2.0.0", "1", "2");
+            assert_req_bump("2.0.0", "^1", "^2");
+        }
+
+        #[test]
+        fn caret_minor() {
+            assert_req_bump("1.0.0", "1.0", None);
+            assert_req_bump("1.0.0", "^1.0", None);
+
+            assert_req_bump("1.1.0", "1.0", "1.1");
+            assert_req_bump("1.1.0", "^1.0", "^1.1");
+
+            assert_req_bump("1.1.1", "1.0", "1.1");
+            assert_req_bump("1.1.1", "^1.0", "^1.1");
+
+            assert_req_bump("2.0.0", "1.0", "2.0");
+            assert_req_bump("2.0.0", "^1.0", "^2.0");
+        }
+
+        #[test]
+        fn caret_patch() {
+            assert_req_bump("1.0.0", "1.0.0", None);
+            assert_req_bump("1.0.0", "^1.0.0", None);
+
+            assert_req_bump("1.1.0", "1.0.0", "1.1.0");
+            assert_req_bump("1.1.0", "^1.0.0", "^1.1.0");
+
+            assert_req_bump("1.1.1", "1.0.0", "1.1.1");
+            assert_req_bump("1.1.1", "^1.0.0", "^1.1.1");
+
+            assert_req_bump("2.0.0", "1.0.0", "2.0.0");
+            assert_req_bump("2.0.0", "^1.0.0", "^2.0.0");
+        }
+
+        #[test]
+        fn tilde_major() {
+            assert_req_bump("1.0.0", "~1", None);
+            assert_req_bump("1.1.0", "~1", None);
+            assert_req_bump("2.0.0", "~1", "~2");
+        }
+
+        #[test]
+        fn tilde_minor() {
+            assert_req_bump("1.0.0", "~1.0", None);
+            assert_req_bump("1.1.0", "~1.0", "~1.1");
+            assert_req_bump("1.1.1", "~1.0", "~1.1");
+            assert_req_bump("2.0.0", "~1.0", "~2.0");
+        }
+
+        #[test]
+        fn tilde_patch() {
+            assert_req_bump("1.0.0", "~1.0.0", None);
+            assert_req_bump("1.1.0", "~1.0.0", "~1.1.0");
+            assert_req_bump("1.1.1", "~1.0.0", "~1.1.1");
+            assert_req_bump("2.0.0", "~1.0.0", "~2.0.0");
+        }
+
+        #[test]
+        fn equal_major() {
+            assert_req_bump("1.0.0", "=1", None);
+            assert_req_bump("1.1.0", "=1", None);
+            assert_req_bump("2.0.0", "=1", "=2");
+        }
+
+        #[test]
+        fn equal_minor() {
+            assert_req_bump("1.0.0", "=1.0", None);
+            assert_req_bump("1.1.0", "=1.0", "=1.1");
+            assert_req_bump("1.1.1", "=1.0", "=1.1");
+            assert_req_bump("2.0.0", "=1.0", "=2.0");
+        }
+
+        #[test]
+        fn equal_patch() {
+            assert_req_bump("1.0.0", "=1.0.0", None);
+            assert_req_bump("1.1.0", "=1.0.0", "=1.1.0");
+            assert_req_bump("1.1.1", "=1.0.0", "=1.1.1");
+            assert_req_bump("2.0.0", "=1.0.0", "=2.0.0");
+        }
+    }
+}
diff --git a/src/doc/src/reference/unstable.md b/src/doc/src/reference/unstable.md
index fce26e146c5..060d6ffb644 100644
--- a/src/doc/src/reference/unstable.md
+++ b/src/doc/src/reference/unstable.md
@@ -73,6 +73,7 @@ For the latest nightly, see the [nightly version] of this page.
     * [public-dependency](#public-dependency) --- Allows dependencies to be classified as either public or private.
     * [msrv-policy](#msrv-policy) --- MSRV-aware resolver and version selection
     * [precise-pre-release](#precise-pre-release) --- Allows pre-release versions to be selected with `update --precise`
+    * [update-breaking](#update-breaking) --- Allows upgrading to breaking versions with `update --breaking`
 * Output behavior
     * [out-dir](#out-dir) --- Adds a directory where artifacts are copied to.
     * [Different binary name](#different-binary-name) --- Assign a name to the built binary that is separate from the crate name.
@@ -378,6 +379,25 @@ It's possible to update `my-dependency` to a pre-release with `update -Zunstable
 This is because `0.1.2-pre.0` is considered compatible with `0.1.1`.
 It would not be possible to upgrade to `0.2.0-pre.0` from `0.1.1` in the same way.
 
+## update-breaking
+
+* Tracking Issue: [#12425](https://github.com/rust-lang/cargo/issues/12425)
+
+This feature allows upgrading dependencies to breaking versions with
+`update --breaking`.
+
+This is essentially migrating `cargo upgrade` from `cargo-edit` into Cargo itself, 
+and involves making changes to the `Cargo.toml` manifests, not just the lock file.
+
+When doing a breaking update, Cargo will keep all non-breaking dependencies
+unchanged. It will also not change any dependencies that use a different version
+operator than the default caret. Also, it will not upgrade any renamed package
+dependencies. Example:
+
+```sh
+cargo +nightly update --breaking -Z unstable-options
+```
+
 ## build-std
 * Tracking Repository: <https://github.com/rust-lang/wg-cargo-std-aware>
 
diff --git a/tests/testsuite/cargo_update/help/stdout.term.svg b/tests/testsuite/cargo_update/help/stdout.term.svg
index 9642c49d2a2..565032d8699 100644
--- a/tests/testsuite/cargo_update/help/stdout.term.svg
+++ b/tests/testsuite/cargo_update/help/stdout.term.svg
@@ -1,4 +1,4 @@
-<svg width="852px" height="524px" xmlns="http://www.w3.org/2000/svg">
+<svg width="852px" height="542px" xmlns="http://www.w3.org/2000/svg">
   <style>
     .fg { fill: #AAAAAA }
     .bg { background: #000000 }
@@ -35,45 +35,47 @@
 </tspan>
     <tspan x="10px" y="154px"><tspan>      </tspan><tspan class="fg-cyan bold">--precise</tspan><tspan class="fg-cyan"> </tspan><tspan class="fg-cyan">&lt;PRECISE&gt;</tspan><tspan>   Update [SPEC] to exactly PRECISE</tspan>
 </tspan>
-    <tspan x="10px" y="172px"><tspan>  </tspan><tspan class="fg-cyan bold">-v</tspan><tspan>, </tspan><tspan class="fg-cyan bold">--verbose</tspan><tspan class="fg-cyan">...</tspan><tspan>          Use verbose output (-vv very verbose/build.rs output)</tspan>
+    <tspan x="10px" y="172px"><tspan>  </tspan><tspan class="fg-cyan bold">-b</tspan><tspan>, </tspan><tspan class="fg-cyan bold">--breaking</tspan><tspan>            Upgrade [SPEC] to latest breaking versions, unless pinned (unstable)</tspan>
 </tspan>
-    <tspan x="10px" y="190px"><tspan>  </tspan><tspan class="fg-cyan bold">-q</tspan><tspan>, </tspan><tspan class="fg-cyan bold">--quiet</tspan><tspan>               Do not print cargo log messages</tspan>
+    <tspan x="10px" y="190px"><tspan>  </tspan><tspan class="fg-cyan bold">-v</tspan><tspan>, </tspan><tspan class="fg-cyan bold">--verbose</tspan><tspan class="fg-cyan">...</tspan><tspan>          Use verbose output (-vv very verbose/build.rs output)</tspan>
 </tspan>
-    <tspan x="10px" y="208px"><tspan>      </tspan><tspan class="fg-cyan bold">--color</tspan><tspan class="fg-cyan"> </tspan><tspan class="fg-cyan">&lt;WHEN&gt;</tspan><tspan>        Coloring: auto, always, never</tspan>
+    <tspan x="10px" y="208px"><tspan>  </tspan><tspan class="fg-cyan bold">-q</tspan><tspan>, </tspan><tspan class="fg-cyan bold">--quiet</tspan><tspan>               Do not print cargo log messages</tspan>
 </tspan>
-    <tspan x="10px" y="226px"><tspan>      </tspan><tspan class="fg-cyan bold">--config</tspan><tspan class="fg-cyan"> </tspan><tspan class="fg-cyan">&lt;KEY=VALUE&gt;</tspan><tspan>  Override a configuration value</tspan>
+    <tspan x="10px" y="226px"><tspan>      </tspan><tspan class="fg-cyan bold">--color</tspan><tspan class="fg-cyan"> </tspan><tspan class="fg-cyan">&lt;WHEN&gt;</tspan><tspan>        Coloring: auto, always, never</tspan>
 </tspan>
-    <tspan x="10px" y="244px"><tspan>  </tspan><tspan class="fg-cyan bold">-Z</tspan><tspan class="fg-cyan"> </tspan><tspan class="fg-cyan">&lt;FLAG&gt;</tspan><tspan>                 Unstable (nightly-only) flags to Cargo, see 'cargo -Z help' for details</tspan>
+    <tspan x="10px" y="244px"><tspan>      </tspan><tspan class="fg-cyan bold">--config</tspan><tspan class="fg-cyan"> </tspan><tspan class="fg-cyan">&lt;KEY=VALUE&gt;</tspan><tspan>  Override a configuration value</tspan>
 </tspan>
-    <tspan x="10px" y="262px"><tspan>  </tspan><tspan class="fg-cyan bold">-h</tspan><tspan>, </tspan><tspan class="fg-cyan bold">--help</tspan><tspan>                Print help</tspan>
+    <tspan x="10px" y="262px"><tspan>  </tspan><tspan class="fg-cyan bold">-Z</tspan><tspan class="fg-cyan"> </tspan><tspan class="fg-cyan">&lt;FLAG&gt;</tspan><tspan>                 Unstable (nightly-only) flags to Cargo, see 'cargo -Z help' for details</tspan>
 </tspan>
-    <tspan x="10px" y="280px">
+    <tspan x="10px" y="280px"><tspan>  </tspan><tspan class="fg-cyan bold">-h</tspan><tspan>, </tspan><tspan class="fg-cyan bold">--help</tspan><tspan>                Print help</tspan>
 </tspan>
-    <tspan x="10px" y="298px"><tspan class="fg-green bold">Package Selection:</tspan>
+    <tspan x="10px" y="298px">
 </tspan>
-    <tspan x="10px" y="316px"><tspan>  </tspan><tspan class="fg-cyan bold">-w</tspan><tspan>, </tspan><tspan class="fg-cyan bold">--workspace</tspan><tspan>  Only update the workspace packages</tspan>
+    <tspan x="10px" y="316px"><tspan class="fg-green bold">Package Selection:</tspan>
 </tspan>
-    <tspan x="10px" y="334px"><tspan>  </tspan><tspan class="fg-cyan">[SPEC]...</tspan><tspan>    Package to update</tspan>
+    <tspan x="10px" y="334px"><tspan>  </tspan><tspan class="fg-cyan bold">-w</tspan><tspan>, </tspan><tspan class="fg-cyan bold">--workspace</tspan><tspan>  Only update the workspace packages</tspan>
 </tspan>
-    <tspan x="10px" y="352px">
+    <tspan x="10px" y="352px"><tspan>  </tspan><tspan class="fg-cyan">[SPEC]...</tspan><tspan>    Package to update</tspan>
 </tspan>
-    <tspan x="10px" y="370px"><tspan class="fg-green bold">Manifest Options:</tspan>
+    <tspan x="10px" y="370px">
 </tspan>
-    <tspan x="10px" y="388px"><tspan>      </tspan><tspan class="fg-cyan bold">--manifest-path</tspan><tspan class="fg-cyan"> </tspan><tspan class="fg-cyan">&lt;PATH&gt;</tspan><tspan>  Path to Cargo.toml</tspan>
+    <tspan x="10px" y="388px"><tspan class="fg-green bold">Manifest Options:</tspan>
 </tspan>
-    <tspan x="10px" y="406px"><tspan>      </tspan><tspan class="fg-cyan bold">--ignore-rust-version</tspan><tspan>   Ignore `rust-version` specification in packages (unstable)</tspan>
+    <tspan x="10px" y="406px"><tspan>      </tspan><tspan class="fg-cyan bold">--manifest-path</tspan><tspan class="fg-cyan"> </tspan><tspan class="fg-cyan">&lt;PATH&gt;</tspan><tspan>  Path to Cargo.toml</tspan>
 </tspan>
-    <tspan x="10px" y="424px"><tspan>      </tspan><tspan class="fg-cyan bold">--locked</tspan><tspan>                Assert that `Cargo.lock` will remain unchanged</tspan>
+    <tspan x="10px" y="424px"><tspan>      </tspan><tspan class="fg-cyan bold">--ignore-rust-version</tspan><tspan>   Ignore `rust-version` specification in packages (unstable)</tspan>
 </tspan>
-    <tspan x="10px" y="442px"><tspan>      </tspan><tspan class="fg-cyan bold">--offline</tspan><tspan>               Run without accessing the network</tspan>
+    <tspan x="10px" y="442px"><tspan>      </tspan><tspan class="fg-cyan bold">--locked</tspan><tspan>                Assert that `Cargo.lock` will remain unchanged</tspan>
 </tspan>
-    <tspan x="10px" y="460px"><tspan>      </tspan><tspan class="fg-cyan bold">--frozen</tspan><tspan>                Equivalent to specifying both --locked and --offline</tspan>
+    <tspan x="10px" y="460px"><tspan>      </tspan><tspan class="fg-cyan bold">--offline</tspan><tspan>               Run without accessing the network</tspan>
 </tspan>
-    <tspan x="10px" y="478px">
+    <tspan x="10px" y="478px"><tspan>      </tspan><tspan class="fg-cyan bold">--frozen</tspan><tspan>                Equivalent to specifying both --locked and --offline</tspan>
 </tspan>
-    <tspan x="10px" y="496px"><tspan>Run `</tspan><tspan class="fg-cyan bold">cargo help update</tspan><tspan class="bold">` for more detailed information.</tspan>
+    <tspan x="10px" y="496px">
 </tspan>
-    <tspan x="10px" y="514px">
+    <tspan x="10px" y="514px"><tspan>Run `</tspan><tspan class="fg-cyan bold">cargo help update</tspan><tspan class="bold">` for more detailed information.</tspan>
+</tspan>
+    <tspan x="10px" y="532px">
 </tspan>
   </text>
 
diff --git a/tests/testsuite/update.rs b/tests/testsuite/update.rs
index 609fc59736f..15f0f9e5b09 100644
--- a/tests/testsuite/update.rs
+++ b/tests/testsuite/update.rs
@@ -1658,8 +1658,13 @@ fn update_breaking_unstable() {
 
     p.cargo("update --breaking")
         .masquerade_as_nightly_cargo(&["update-breaking"])
-        .with_status(1)
-        .with_stderr_contains("[ERROR] unexpected argument '--breaking' found")
+        .with_status(101)
+        .with_stderr(
+            "\
+[ERROR] the `--breaking` flag is unstable, pass `-Z unstable-options` to enable it
+See https://github.com/rust-lang/cargo/issues/12425 for more information about the `--breaking` flag.
+",
+        )
         .run();
 }
 
@@ -1707,9 +1712,19 @@ fn update_breaking_dry_run() {
     Package::new("incompatible", "2.0.0").publish();
     Package::new("ws", "2.0.0").publish();
 
-    p.cargo("update --dry-run --breaking")
-        .with_status(1)
-        .with_stderr_contains("[ERROR] unexpected argument '--breaking' found")
+    p.cargo("update -Zunstable-options --dry-run --breaking")
+        .masquerade_as_nightly_cargo(&["update-breaking"])
+        .with_stderr(
+            "\
+[UPDATING] `dummy-registry` index
+[UPGRADING] incompatible ^1.0 -> ^2.0
+[UPGRADING] ws ^1.0 -> ^2.0
+[LOCKING] 2 packages to latest compatible versions
+[UPDATING] incompatible v1.0.0 -> v2.0.0
+[UPDATING] ws v1.0.0 -> v2.0.0
+[WARNING] aborting update due to dry run
+",
+        )
         .run();
 
     let root_manifest_after = p.read_file("Cargo.toml");
@@ -1864,9 +1879,34 @@ fn update_breaking() {
         .publish();
     Package::new("multiple-source-types", "2.0.0").publish();
 
-    p.cargo("update --breaking")
-        .with_status(1)
-        .with_stderr_contains("[ERROR] unexpected argument '--breaking' found")
+    p.cargo("update -Zunstable-options --breaking")
+        .masquerade_as_nightly_cargo(&["update-breaking"])
+        .with_stderr(
+            "\
+[UPDATING] `alternative` index
+[UPGRADING] multiple-registries ^2.0 -> ^3.0
+[UPDATING] `dummy-registry` index
+[UPGRADING] multiple-source-types ^1.0 -> ^2.0
+[UPGRADING] multiple-versions ^2.0 -> ^3.0
+[UPGRADING] shared ^1.0 -> ^2.0
+[UPGRADING] alternative-1 ^1.0 -> ^2.0
+[UPGRADING] alternative-2 ^1.0 -> ^2.0
+[UPGRADING] incompatible ^1.0 -> ^2.0
+[UPGRADING] multiple-registries ^1.0 -> ^2.0
+[UPGRADING] multiple-versions ^1.0 -> ^3.0
+[UPGRADING] ws ^1.0 -> ^2.0
+[LOCKING] 9 packages to latest compatible versions
+[UPDATING] alternative-1 v1.0.0 (registry `alternative`) -> v2.0.0
+[UPDATING] alternative-2 v1.0.0 (registry `alternative`) -> v2.0.0
+[UPDATING] incompatible v1.0.0 -> v2.0.0
+[UPDATING] multiple-registries v2.0.0 (registry `alternative`) -> v3.0.0
+[UPDATING] multiple-registries v1.0.0 -> v2.0.0
+[UPDATING] multiple-source-types v1.0.0 -> v2.0.0
+[ADDING] multiple-versions v3.0.0
+[UPDATING] shared v1.0.0 -> v2.0.0
+[UPDATING] ws v1.0.0 -> v2.0.0
+",
+        )
         .run();
 
     let root_manifest = p.read_file("Cargo.toml");
@@ -1880,8 +1920,9 @@ fn update_breaking() {
                 members  =  ["foo", "bar"]
 
                 [workspace.dependencies]
-                ws  =  "1.0"  # This line gets partially rewritten
-            "#]],
+                ws  =  "2.0"  # This line gets partially rewritten
+            
+"#]],
     );
 
     let foo_manifest = p.read_file("foo/Cargo.toml");
@@ -1900,22 +1941,22 @@ fn update_breaking() {
 
                 [dependencies]
                 compatible  =  "1.0"  # Comment
-                incompatible  =  "1.0"  # Comment
+                incompatible  =  "2.0"  # Comment
                 pinned  =  "=1.0"  # Comment
                 less-than  =  "<99.0"  # Comment
                 renamed-to  =  { package  =  "renamed-from", version  =  "1.0" }  # Comment
                 pre-release  =  "1.0"  # Comment
                 yanked  =  "1.0"  # Comment
                 ws.workspace  =  true  # Comment
-                shared  =  "1.0"  # Comment
-                multiple-versions  =  "1.0"  # Comment
-                alternative-1  =  { registry  =  "alternative", version  =  "1.0" }  # Comment
-                multiple-registries  =  "1.0"  # Comment
+                shared  =  "2.0"  # Comment
+                multiple-versions  =  "3.0"  # Comment
+                alternative-1  =  { registry  =  "alternative", version  =  "2.0" }  # Comment
+                multiple-registries  =  "2.0"  # Comment
                 bar  =  { path  =  "../bar", registry  =  "alternative", version  =  "1.0.0" }  # Comment
                 multiple-source-types  =  { path  =  "../multiple-source-types", version  =  "1.0.0" }  # Comment
 
                 [dependencies.alternative-2]  # Comment
-                version  =  "1.0"  # Comment
+                version  =  "2.0"  # Comment
                 registry  =  "alternative"  # Comment
             "#]],
     );
@@ -1933,10 +1974,10 @@ fn update_breaking() {
                 authors = []
 
                 [dependencies]
-                shared = "1.0"
-                multiple-versions = "2.0"
-                multiple-registries  =  { registry  =  "alternative", version  =  "2.0" }  # Comment
-                multiple-source-types  =  "1.0"  # Comment
+                shared = "2.0"
+                multiple-versions = "3.0"
+                multiple-registries  =  { registry  =  "alternative", version  =  "3.0" }  # Comment
+                multiple-source-types  =  "2.0"  # Comment
             "#]],
     );
 
@@ -1945,20 +1986,11 @@ fn update_breaking() {
             "\
 [UPDATING] `alternative` index
 [UPDATING] `dummy-registry` index
-[LOCKING] 10 packages to latest compatible versions
-[UPDATING] alternative-1 v1.0.0 (registry `alternative`) -> v1.0.1 (latest: v2.0.0)
-[UPDATING] alternative-2 v1.0.0 (registry `alternative`) -> v1.0.1 (latest: v2.0.0)
+[LOCKING] 4 packages to latest compatible versions
 [UPDATING] compatible v1.0.0 -> v1.0.1
-[UPDATING] incompatible v1.0.0 -> v1.0.1 (latest: v2.0.0)
 [UPDATING] less-than v1.0.0 -> v2.0.0
-[REMOVING] multiple-versions v1.0.0
-[REMOVING] multiple-versions v2.0.0
-[ADDING] multiple-versions v1.0.1 (latest: v3.0.0)
-[ADDING] multiple-versions v2.0.1 (latest: v3.0.0)
 [UPDATING] pinned v1.0.0 -> v1.0.1 (latest: v2.0.0)
 [UPDATING] renamed-from v1.0.0 -> v1.0.1 (latest: v2.0.0)
-[UPDATING] ws v1.0.0 -> v1.0.1 (latest: v2.0.0)
-[NOTE] pass `--verbose` to see 4 unchanged dependencies behind latest
 ",
         )
         .run();
@@ -2044,20 +2076,20 @@ fn update_breaking_specific_packages() {
     Package::new("ws", "2.0.0").publish();
     Package::new("transitive-incompatible", "2.0.0").publish();
 
-    p.cargo("update --breaking just-foo shared ws")
-        .with_status(1)
-        .with_stderr_contains("[ERROR] unexpected argument '--breaking' found")
-        .run();
-
-    p.cargo("update just-foo shared ws")
+    p.cargo("update -Zunstable-options --breaking just-foo shared ws")
+        .masquerade_as_nightly_cargo(&["update-breaking"])
         .with_stderr(
             "\
 [UPDATING] `[..]` index
-[LOCKING] 3 packages to latest compatible versions
-[UPDATING] just-foo v1.0.0 -> v1.0.1 (latest: v2.0.0)
-[UPDATING] shared v1.0.0 -> v1.0.1 (latest: v2.0.0)
-[UPDATING] ws v1.0.0 -> v1.0.1 (latest: v2.0.0)
-[NOTE] pass `--verbose` to see 3 unchanged dependencies behind latest
+[UPGRADING] shared ^1.0 -> ^2.0
+[UPGRADING] ws ^1.0 -> ^2.0
+[UPGRADING] just-foo ^1.0 -> ^2.0
+[LOCKING] 5 packages to latest compatible versions
+[UPDATING] just-foo v1.0.0 -> v2.0.0
+[UPDATING] shared v1.0.0 -> v2.0.0
+[UPDATING] transitive-compatible v1.0.0 -> v1.0.1
+[UPDATING] transitive-incompatible v1.0.0 -> v2.0.0
+[UPDATING] ws v1.0.0 -> v2.0.0
 ",
         )
         .run();