Auto merge of #13349 - epage:config, r=weihanglo

fix(config): Deprecate non-extension files

### What does this PR try to resolve?

In #7295 (released in 1.39), we said we'd want to warn on use of
`.cargo/config` after about 6 months.  Over 4 years later, we are now
getting that warning.

This is important for addressing user confusion, like in
https://www.reddit.com/r/rust/comments/19fd5q2/cargoconfig/

### How should we test and review this PR?

It'll be important to look at the individual commits as one updates tests from using `.cargo/config` to `.cargo/config.toml` which touches a lot of code.

I added a test for `.cargo/config` in a separate commit so you can see how the output changes.

### Additional information

Discussed on [zulip](https://rust-lang.zulipchat.com/#narrow/stream/246057-t-cargo/topic/Deprecating.20credential.20provider.20default.3F)

crates/cargo-test-support/src/registry.rs

@@ -279,7 +279,7 @@ impl RegistryBuilder {
     /// Initializes the registry.
     #[must_use]
     pub fn build(self) -> TestRegistry {
-        let config_path = paths::home().join(".cargo/config");
+        let config_path = paths::home().join(".cargo/config.toml");
         t!(fs::create_dir_all(config_path.parent().unwrap()));
         let prefix = if let Some(alternative) = &self.alternative {
             format!("{alternative}-")
@@ -1195,7 +1195,7 @@ impl Package {
     /// Creates a new package builder.
     /// Call `publish()` to finalize and build the package.
     pub fn new(name: &str, vers: &str) -> Package {
-        let config = paths::home().join(".cargo/config");
+        let config = paths::home().join(".cargo/config.toml");
         if !config.exists() {
             init();
         }

src/cargo/util/config/mod.rs

@@ -1507,7 +1507,7 @@ impl Config {
         let possible_with_extension = dir.join(format!("{}.toml", filename_without_extension));
 
         if possible.exists() {
-            if warn && possible_with_extension.exists() {
+            if warn {
                 // We don't want to print a warning if the version
                 // without the extension is just a symlink to the version
                 // WITH an extension, which people may want to do to
@@ -1520,12 +1520,22 @@ impl Config {
                 };
 
                 if !skip_warning {
-                    self.shell().warn(format!(
-                        "Both `{}` and `{}` exist. Using `{}`",
-                        possible.display(),
-                        possible_with_extension.display(),
-                        possible.display()
-                    ))?;
+                    if possible_with_extension.exists() {
+                        self.shell().warn(format!(
+                            "Both `{}` and `{}` exist. Using `{}`",
+                            possible.display(),
+                            possible_with_extension.display(),
+                            possible.display()
+                        ))?;
+                    } else {
+                        self.shell().warn(format!(
+                            "`{}` is deprecated in favor of `{filename_without_extension}.toml`",
+                            possible.display(),
+                        ))?;
+                        self.shell().note(
+                            format!("If you need to support cargo 1.38 or earlier, you can symlink `{filename_without_extension}` to `{filename_without_extension}.toml`"),
+                        )?;
+                    }
                 }
             }
 

tests/testsuite/alt_registry.rs

@@ -621,7 +621,7 @@ You may press ctrl-c to skip waiting; the crate should be available shortly.
 fn passwords_in_registries_index_url_forbidden() {
     registry::alt_init();
 
-    let config = paths::home().join(".cargo/config");
+    let config = paths::home().join(".cargo/config.toml");
 
     fs::write(
         config,
@@ -638,7 +638,7 @@ fn passwords_in_registries_index_url_forbidden() {
         .with_status(101)
         .with_stderr(
             "\
-error: invalid index URL for registry `alternative` defined in [..]/home/.cargo/config
+error: invalid index URL for registry `alternative` defined in [..]/home/.cargo/config.toml
 
 Caused by:
   registry URLs may not contain passwords
@@ -1153,7 +1153,7 @@ fn unknown_registry() {
         .publish();
 
     // Remove "alternative" from config.
-    let cfg_path = paths::home().join(".cargo/config");
+    let cfg_path = paths::home().join(".cargo/config.toml");
     let mut config = fs::read_to_string(&cfg_path).unwrap();
     let start = config.find("[registries.alternative]").unwrap();
     config.insert(start, '#');
@@ -1296,7 +1296,7 @@ fn unknown_registry() {
 #[cargo_test]
 fn registries_index_relative_url() {
     registry::alt_init();
-    let config = paths::root().join(".cargo/config");
+    let config = paths::root().join(".cargo/config.toml");
     fs::create_dir_all(config.parent().unwrap()).unwrap();
     fs::write(
         &config,
@@ -1343,7 +1343,7 @@ fn registries_index_relative_url() {
 #[cargo_test]
 fn registries_index_relative_path_not_allowed() {
     registry::alt_init();
-    let config = paths::root().join(".cargo/config");
+    let config = paths::root().join(".cargo/config.toml");
     fs::create_dir_all(config.parent().unwrap()).unwrap();
     fs::write(
         &config,
@@ -1379,7 +1379,7 @@ fn registries_index_relative_path_not_allowed() {
 error: failed to parse manifest at `{root}/foo/Cargo.toml`
 
 Caused by:
-  invalid index URL for registry `relative` defined in [..]/.cargo/config
+  invalid index URL for registry `relative` defined in [..]/.cargo/config.toml
 
 Caused by:
   invalid url `alternative-registry`: relative URL without a base

tests/testsuite/bad_config.rs

@@ -9,7 +9,7 @@ fn bad1() {
     let p = project()
         .file("src/lib.rs", "")
         .file(
-            ".cargo/config",
+            ".cargo/config.toml",
             r#"
                   [target]
                   nonexistent-target = "foo"
@@ -21,7 +21,7 @@ fn bad1() {
         .with_stderr(
             "\
 [ERROR] expected table for configuration key `target.nonexistent-target`, \
-but found string in [..]/config
+but found string in [..]/config.toml
 ",
         )
         .run();
@@ -32,7 +32,7 @@ fn bad2() {
     let p = project()
         .file("src/lib.rs", "")
         .file(
-            ".cargo/config",
+            ".cargo/config.toml",
             r#"
                   [http]
                     proxy = 3.0
@@ -46,7 +46,7 @@ fn bad2() {
 [ERROR] could not load Cargo configuration
 
 Caused by:
-  failed to load TOML configuration from `[..]config`
+  failed to load TOML configuration from `[..]config.toml`
 
 Caused by:
   failed to parse key `http`
@@ -67,7 +67,7 @@ fn bad3() {
     let p = project()
         .file("src/lib.rs", "")
         .file(
-            ".cargo/config",
+            ".cargo/config.toml",
             r#"
                 [http]
                   proxy = true
@@ -84,7 +84,7 @@ fn bad3() {
 error: failed to update registry [..]
 
 Caused by:
-  error in [..]config: `http.proxy` expected a string, but found a boolean
+  error in [..]config.toml: `http.proxy` expected a string, but found a boolean
 ",
         )
         .run();
@@ -94,7 +94,7 @@ Caused by:
 fn bad4() {
     let p = project()
         .file(
-            ".cargo/config",
+            ".cargo/config.toml",
             r#"
                 [cargo-new]
                   vcs = false
@@ -108,7 +108,7 @@ fn bad4() {
 [ERROR] Failed to create package `foo` at `[..]`
 
 Caused by:
-  error in [..]config: `cargo-new.vcs` expected a string, but found a boolean
+  error in [..]config.toml: `cargo-new.vcs` expected a string, but found a boolean
 ",
         )
         .run();
@@ -120,7 +120,7 @@ fn bad6() {
     let p = project()
         .file("src/lib.rs", "")
         .file(
-            ".cargo/config",
+            ".cargo/config.toml",
             r#"
                 [http]
                   user-agent = true
@@ -137,7 +137,7 @@ fn bad6() {
 error: failed to update registry [..]
 
 Caused by:
-  error in [..]config: `http.user-agent` expected a string, but found a boolean
+  error in [..]config.toml: `http.user-agent` expected a string, but found a boolean
 ",
         )
         .run();
@@ -158,7 +158,7 @@ fn invalid_global_config() {
                 foo = "0.1.0"
             "#,
         )
-        .file(".cargo/config", "4")
+        .file(".cargo/config.toml", "4")
         .file("src/lib.rs", "")
         .build();
 
@@ -788,7 +788,7 @@ or workspace dependency to use. This will be considered an error in future versi
 #[cargo_test]
 fn invalid_toml_historically_allowed_fails() {
     let p = project()
-        .file(".cargo/config", "[bar] baz = 2")
+        .file(".cargo/config.toml", "[bar] baz = 2")
         .file("src/main.rs", "fn main() {}")
         .build();
 
@@ -880,7 +880,7 @@ use `rev = \"foo\"` in the dependency declaration.
 fn bad_source_config1() {
     let p = project()
         .file("src/lib.rs", "")
-        .file(".cargo/config", "[source.foo]")
+        .file(".cargo/config.toml", "[source.foo]")
         .build();
 
     p.cargo("check")
@@ -906,7 +906,7 @@ fn bad_source_config2() {
         )
         .file("src/lib.rs", "")
         .file(
-            ".cargo/config",
+            ".cargo/config.toml",
             r#"
                 [source.crates-io]
                 registry = 'http://example.com'
@@ -952,7 +952,7 @@ fn bad_source_config3() {
         )
         .file("src/lib.rs", "")
         .file(
-            ".cargo/config",
+            ".cargo/config.toml",
             r#"
                 [source.crates-io]
                 registry = 'https://example.com'
@@ -997,7 +997,7 @@ fn bad_source_config4() {
         )
         .file("src/lib.rs", "")
         .file(
-            ".cargo/config",
+            ".cargo/config.toml",
             r#"
                 [source.crates-io]
                 replace-with = 'bar'
@@ -1046,7 +1046,7 @@ fn bad_source_config5() {
         )
         .file("src/lib.rs", "")
         .file(
-            ".cargo/config",
+            ".cargo/config.toml",
             r#"
                 [source.crates-io]
                 registry = 'https://example.com'
@@ -1120,7 +1120,7 @@ fn bad_source_config6() {
         )
         .file("src/lib.rs", "")
         .file(
-            ".cargo/config",
+            ".cargo/config.toml",
             r#"
                 [source.crates-io]
                 registry = 'https://example.com'
@@ -1133,10 +1133,10 @@ fn bad_source_config6() {
         .with_status(101)
         .with_stderr(
             "\
-[ERROR] error in [..]/foo/.cargo/config: could not load config key `source.crates-io.replace-with`
+[ERROR] error in [..]/foo/.cargo/config.toml: could not load config key `source.crates-io.replace-with`
 
 Caused by:
-  error in [..]/foo/.cargo/config: `source.crates-io.replace-with` expected a string, but found a array
+  error in [..]/foo/.cargo/config.toml: `source.crates-io.replace-with` expected a string, but found a array
 "
         )
         .run();
@@ -1207,7 +1207,7 @@ fn bad_source_config7() {
         )
         .file("src/lib.rs", "")
         .file(
-            ".cargo/config",
+            ".cargo/config.toml",
             r#"
                 [source.foo]
                 registry = 'https://example.com'
@@ -1241,7 +1241,7 @@ fn bad_source_config8() {
         )
         .file("src/lib.rs", "")
         .file(
-            ".cargo/config",
+            ".cargo/config.toml",
             r#"
                 [source.foo]
                 branch = "somebranch"
@@ -1253,7 +1253,7 @@ fn bad_source_config8() {
         .with_status(101)
         .with_stderr(
             "[ERROR] source definition `source.foo` specifies `branch`, \
-             but that requires a `git` key to be specified (in [..]/foo/.cargo/config)",
+             but that requires a `git` key to be specified (in [..]/foo/.cargo/config.toml)",
         )
         .run();
 }
@@ -1532,7 +1532,7 @@ fn bad_target_cfg() {
     // the message.
     let p = project()
         .file(
-            ".cargo/config",
+            ".cargo/config.toml",
             r#"
             [target.'cfg(not(target_os = "none"))']
             runner = false
@@ -1545,17 +1545,17 @@ fn bad_target_cfg() {
         .with_status(101)
         .with_stderr(
             "\
-[ERROR] error in [..]/foo/.cargo/config: \
+[ERROR] error in [..]/foo/.cargo/config.toml: \
 could not load config key `target.\"cfg(not(target_os = \\\"none\\\"))\".runner`
 
 Caused by:
-  error in [..]/foo/.cargo/config: \
+  error in [..]/foo/.cargo/config.toml: \
   could not load config key `target.\"cfg(not(target_os = \\\"none\\\"))\".runner`
 
 Caused by:
   invalid configuration for key `target.\"cfg(not(target_os = \\\"none\\\"))\".runner`
   expected a string or array of strings, but found a boolean for \
-  `target.\"cfg(not(target_os = \\\"none\\\"))\".runner` in [..]/foo/.cargo/config
+  `target.\"cfg(not(target_os = \\\"none\\\"))\".runner` in [..]/foo/.cargo/config.toml
 ",
         )
         .run();
@@ -1571,7 +1571,7 @@ fn bad_target_links_overrides() {
     // currently is designed with serde.
     let p = project()
         .file(
-            ".cargo/config",
+            ".cargo/config.toml",
             &format!(
                 r#"
                 [target.{}.somelib]
@@ -1587,12 +1587,12 @@ fn bad_target_links_overrides() {
         .with_status(101)
         .with_stderr(
             "[ERROR] Only `-l` and `-L` flags are allowed in target config \
-             `target.[..].rustc-flags` (in [..]foo/.cargo/config): `foo`",
+             `target.[..].rustc-flags` (in [..]foo/.cargo/config.toml): `foo`",
         )
         .run();
 
     p.change_file(
-        ".cargo/config",
+        ".cargo/config.toml",
         &format!(
             "[target.{}.somelib]
             warning = \"foo\"
@@ -1611,7 +1611,7 @@ fn redefined_sources() {
     // Cannot define a source multiple times.
     let p = project()
         .file(
-            ".cargo/config",
+            ".cargo/config.toml",
             r#"
             [source.foo]
             registry = "https://github.com/rust-lang/crates.io-index"
@@ -1632,7 +1632,7 @@ note: Sources are not allowed to be defined multiple times.
         .run();
 
     p.change_file(
-        ".cargo/config",
+        ".cargo/config.toml",
         r#"
         [source.one]
         directory = "index"