perf(pm): restore cold_path() hints in the vendored aube hot loops

.claude/skills/aube-bump/SKILL.md

@@ -245,7 +245,7 @@ applies. Reverting was correct. Let the tests arbitrate; don't defend a graft.
 Grep after every bump — if one vanished, a resolution was wrong:
 
 ```sh
-grep -rn "workspace_markers\|lockfile_basename\|EmbedderProfile\|read_branded_pnpm_config\|env_prefix\|cache_namespace\|engine_context\|env_overlay\|path_prepends\|runtime_node" vendor/aube/crates
+grep -rn "workspace_markers\|lockfile_basename\|EmbedderProfile\|read_branded_pnpm_config\|env_prefix\|cache_namespace\|engine_context\|env_overlay\|path_prepends\|runtime_node\|cold_path" vendor/aube/crates
 ```
 
 - **Embedder profile plumbing** — `env_prefix`, `cache_namespace`, `lockfile_basename`,
@@ -268,6 +268,17 @@ grep -rn "workspace_markers\|lockfile_basename\|EmbedderProfile\|read_branded_pn
   it to show as fork delta rather than converge on the next bump.
 - **Registry** — `registry_url_for` returns an owned `String` (a `namedRegistries` route lookup borrows
   through a lock guard), mTLS/`npmAlwaysAuth`, the Android hickory carve-out.
+- **`cold_path()` hints + the 1.95 MSRV** — `core::hint::cold_path()` on the rare arms of the hot
+  install loops (`aube-linker/materialize.rs` link fallbacks, `aube-resolver/semver_util.rs` cache
+  misses, `aube-lockfile/pnpm/subset.rs` parser bails, `aube-store/tarball.rs` validation rejects), and
+  the matching `rust-version = "1.95"` in `vendor/aube/Cargo.toml`. Upstream deliberately holds aube at
+  1.91 for mise's distro packaging; nub does not (it vendors aube and builds on stable), so this is a
+  standing fork delta, NOT a convergence. The `cold_path` grep above catches the hints going missing;
+  the Cargo.toml `rust-version` conflicts on every bump (upstream's 1.91-for-mise comment vs. nub's
+  divergence note) — resolve OURS every time. Behaviorally inert (a codegen hint), so it never changes
+  standalone-aube behavior — it just can't upstream (it would break mise's build floor). nub-cli depends
+  on aube, so `crates/nub-cli/Cargo.toml` sets `rust-version = "1.95"` (the workspace floor stays 1.93);
+  the CI MSRV `Check` job runs the root leg on 1.95.0 and the aube-free nub-phantom leg on 1.93.0.
 - **Runtime / lifecycle-script env** — the embedder runtime seam. `crates/aube-util/src/engine_context.rs`
   is a whole nub-only module (`EngineContext` = process-global `OnceLock<RwLock<..>>`); its
   `runtime_node_dir` / `runtime_node_bin` / `env_overlay` / `path_prepends` / `lifecycle_user_agent_product`

.github/workflows/ci.yml

@@ -150,6 +150,10 @@ jobs:
       - uses: actions/checkout@93cb6efe18208431cddfb8368fd83d5badbf9bfd  # v5.0.1
         with:
           persist-credentials: false
+      # nub-phantom is an excluded, aube-free workspace and keeps the lower 1.93
+      # floor, so it verifies on 1.93.0 first. The root workspace (nub-cli) depends
+      # on the vendored aube, which uses core::hint::cold_path() (stable in 1.95),
+      # so root + nub-native verify on 1.95.0.
       - uses: dtolnay/rust-toolchain@29eef336d9b2848a0b548edc03f92a220660cdb8  # 1.93.0 # zizmor: ignore[impostor-commit,ref-version-mismatch] dtolnay force-pushes its version tags, so pinned SHAs go unreachable; commit verified genuine upstream
         with:
           toolchain: 1.93.0
@@ -162,11 +166,11 @@ jobs:
         with:
           shared-key: ci-check
           save-if: ${{ github.ref == 'refs/heads/main' }}
-      - run: cargo check --all-targets
       - run: cargo check --manifest-path crates/nub-phantom/Cargo.toml --all-targets
       - uses: dtolnay/rust-toolchain@29eef336d9b2848a0b548edc03f92a220660cdb8  # 1.95.0 # zizmor: ignore[impostor-commit,ref-version-mismatch] dtolnay force-pushes its version tags, so pinned SHAs go unreachable; commit verified genuine upstream
         with:
           toolchain: 1.95.0
+      - run: cargo check --all-targets
       - run: cd crates/nub-native && cargo check --locked --all-targets --all-features
       # Real Windows compile + test coverage is the windows-latest leg of the
       # `test` job. The previous fast `x86_64-pc-windows-gnu` cross-check needed

Cargo.toml

@@ -92,6 +92,10 @@ split-debuginfo = "unpacked"
 [workspace.package]
 version = "0.5.0"
 edition = "2024"
+# Workspace floor stays 1.93; only nub-cli needs 1.95 (it depends on the
+# vendored aube, which uses core::hint::cold_path()), so that crate sets its
+# own rust-version rather than raising every member — keeps nub-phantom-core /
+# nub-phantom-scan buildable on 1.93 for the aube-free nub-phantom eval tool.
 rust-version = "1.93"
 license = "MIT"
 repository = "https://github.com/nubjs/nub"

crates/nub-cli/Cargo.toml

@@ -2,7 +2,9 @@
 name = "nub-cli"
 version.workspace = true
 edition.workspace = true
-rust-version.workspace = true
+# 1.95 (above the 1.93 workspace floor) for core::hint::cold_path() in the
+# vendored aube engine, a path dep of nub-cli. See vendor/aube/Cargo.toml.
+rust-version = "1.95"
 license.workspace = true
 repository.workspace = true
 

vendor/aube/Cargo.toml

@@ -33,10 +33,15 @@ panic = "unwind"
 [workspace.package]
 version = "1.32.0"
 edition = "2024"
-# Kept at the floor mise can build with (its distro packaging pins the
-# toolchain) so mise can embed the library crates. CI enforces this via
-# `cargo msrv verify` — bump deliberately, not as a side effect.
-rust-version = "1.91"
+# DELIBERATE NUB FORK DELTA — do not converge to upstream on a sync.
+# Upstream holds this at 1.91 so mise (which embeds aube's library crates and
+# is packaged by distros that pin an old toolchain) can build it. nub does not
+# ship that way: it vendors aube and compiles every binary on current stable,
+# and nub CI does not MSRV-check the vendored tree — so upstream's floor does
+# not bind us. We raise it to 1.95 for core::hint::cold_path() on the rare arms
+# of the hot install loops (linker, resolver cache, lockfile subset parser,
+# tarball validation). Preserve this on every aube bump — see the aube-bump skill.
+rust-version = "1.95"
 license = "MIT"
 repository = "https://github.com/jdx/aube"
 homepage = "https://github.com/jdx/aube"

vendor/aube/crates/aube-linker/src/materialize.rs

@@ -625,6 +625,7 @@ impl Linker {
             let target = pkg_nm_dir.join(rel_path);
 
             if let Err(e) = self.link_file_fresh(stored, rel_path, &target) {
+                core::hint::cold_path();
                 if let Error::MissingStoreFile { .. } = &e {
                     invalidate_stale_index_for_package(&self.store, pkg, self.index_read_key(pkg));
                 }
@@ -862,6 +863,7 @@ impl Linker {
                     }
                 };
                 if let Err(e) = reflink_result {
+                    core::hint::cold_path();
                     // Source-missing short-circuit avoids the misleading
                     // "fell back to copy" trace and the redundant copy
                     // attempt that would just ENOENT for the same reason.
@@ -917,6 +919,7 @@ impl Linker {
             }
             LinkStrategy::Hardlink => {
                 if let Err(e) = std::fs::hard_link(&stored.store_path, dst) {
+                    core::hint::cold_path();
                     if !stored.store_path.exists() {
                         return Err(missing_source());
                     }
@@ -1219,6 +1222,7 @@ impl Linker {
         for (rel_path, stored) in index {
             let target = tmp.join(rel_path);
             if let Err(e) = self.link_file_fresh(stored, rel_path, &target) {
+                core::hint::cold_path();
                 let _ = std::fs::remove_dir_all(&tmp);
                 if let Error::MissingStoreFile { .. } = &e {
                     invalidate_stale_index_for_package(&self.store, pkg, self.index_read_key(pkg));

vendor/aube/crates/aube-lockfile/src/pnpm/subset.rs

@@ -224,7 +224,10 @@ impl<'a> Parser<'a> {
                 }
                 // Any top-level key we don't recognize: bail to serde so
                 // we never silently drop a field a future pnpm adds.
-                _ => return None,
+                _ => {
+                    core::hint::cold_path();
+                    return None;
+                }
             }
         }
 
@@ -304,6 +307,7 @@ impl<'a> Parser<'a> {
                 break;
             }
             if line.indent != min_indent {
+                core::hint::cold_path();
                 return None;
             }
             let (k, v) = split_key(line.body)?;
@@ -350,6 +354,7 @@ impl<'a> Parser<'a> {
                 break;
             }
             if line.indent != 2 {
+                core::hint::cold_path();
                 return None;
             }
             // `<importerPath>:` header. pnpm writes an empty importer
@@ -395,7 +400,10 @@ impl<'a> Parser<'a> {
                 b"devDependencies" => dev_dependencies = Some(specs),
                 b"optionalDependencies" => optional_dependencies = Some(specs),
                 b"skippedOptionalDependencies" => skipped_optional_dependencies = Some(specs),
-                _ => return None,
+                _ => {
+                    core::hint::cold_path();
+                    return None;
+                }
             }
         }
         Some(RawImporter {
@@ -415,6 +423,7 @@ impl<'a> Parser<'a> {
                 break;
             }
             if line.indent != entry_indent {
+                core::hint::cold_path();
                 return None;
             }
             let (name, rest) = split_key(line.body)?;
@@ -432,6 +441,7 @@ impl<'a> Parser<'a> {
                     break;
                 }
                 if c.indent != child_indent {
+                    core::hint::cold_path();
                     return None;
                 }
                 let (ck, cv) = split_key(c.body)?;
@@ -440,7 +450,10 @@ impl<'a> Parser<'a> {
                 match ck {
                     b"specifier" => specifier = Some(scalar_string(cv)?),
                     b"version" => version = Some(scalar_string(cv)?),
-                    _ => return None,
+                    _ => {
+                        core::hint::cold_path();
+                        return None;
+                    }
                 }
             }
             map.insert(
@@ -468,6 +481,7 @@ impl<'a> Parser<'a> {
                 break;
             }
             if line.indent != 2 {
+                core::hint::cold_path();
                 return None;
             }
             let (key, rest) = split_key(line.body)?;
@@ -510,6 +524,7 @@ impl<'a> Parser<'a> {
                 break;
             }
             if line.indent != 2 {
+                core::hint::cold_path();
                 return None;
             }
             let (key, rest) = split_key(line.body)?;
@@ -540,6 +555,7 @@ impl<'a> Parser<'a> {
                 break;
             }
             if line.indent != indent {
+                core::hint::cold_path();
                 return None;
             }
             let (key, rest) = split_key(line.body)?;
@@ -560,7 +576,10 @@ impl<'a> Parser<'a> {
                 b"transitivePeerDependencies" => {
                     transitive_peer_dependencies = Some(self.parse_seq_value(rest, indent + 2)?);
                 }
-                _ => return None,
+                _ => {
+                    core::hint::cold_path();
+                    return None;
+                }
             }
         }
         Some(RawSnapshot {
@@ -637,6 +656,7 @@ fn split_key(body: &[u8]) -> Option<(&[u8], Option<&[u8]>)> {
         }
         i += 1;
     }
+    core::hint::cold_path();
     None
 }
 

vendor/aube/crates/aube-resolver/src/semver_util.rs

@@ -509,6 +509,7 @@ fn with_cached_range<R>(range_str: &str, f: impl FnOnce(Option<&node_semver::Ran
     CACHE.with(|cell| {
         let mut map = cell.borrow_mut();
         if !map.contains_key(range_str) {
+            core::hint::cold_path();
             let parsed = node_semver::Range::parse(range_str).ok();
             map.insert(range_str.to_string(), parsed);
         }
@@ -527,6 +528,7 @@ fn with_cached_version<R>(version: &str, f: impl FnOnce(Option<&node_semver::Ver
     CACHE.with(|cell| {
         let mut map = cell.borrow_mut();
         if !map.contains_key(version) {
+            core::hint::cold_path();
             let parsed = node_semver::Version::parse(version).ok();
             map.insert(version.to_string(), parsed);
         }

vendor/aube/crates/aube-store/src/tarball.rs

@@ -343,6 +343,7 @@ impl Store {
         for entry in archive.entries().map_err(|e| Error::Tar(e.to_string()))? {
             entries_seen += 1;
             if entries_seen > MAX_TARBALL_ENTRIES {
+                core::hint::cold_path();
                 return Err(Error::Tar(format!(
                     "tarball exceeds entry cap of {MAX_TARBALL_ENTRIES}"
                 )));
@@ -381,6 +382,7 @@ impl Store {
                 entry_type,
                 tar::EntryType::Regular | tar::EntryType::Continuous
             ) {
+                core::hint::cold_path();
                 return Err(Error::Tar(format!(
                     "tarball entry type {entry_type:?} is not allowed"
                 )));
@@ -395,6 +397,7 @@ impl Store {
                 .size()
                 .map_err(|e| Error::Tar(e.to_string()))?;
             if declared > MAX_TARBALL_ENTRY_BYTES {
+                core::hint::cold_path();
                 return Err(Error::Tar(format!(
                     "tarball entry exceeds per-entry cap: {declared} bytes > {MAX_TARBALL_ENTRY_BYTES}"
                 )));
@@ -425,6 +428,7 @@ impl Store {
             // non-empty stream. Synthetic-entry injection: header
             // claims empty file, real bytes go to disk.
             if declared == 0 && !content.is_empty() {
+                core::hint::cold_path();
                 return Err(Error::Tar(format!(
                     "tarball entry declared 0 bytes but yielded {} bytes",
                     content.len()