Trim ~2 MB from the release binary without touching hot paths

mordant-baseline.toml

@@ -8,6 +8,7 @@
 "defaulted_failure:src/bun_core/string/immutable.rs" = 1
 
 [bun_css]
+"derived_field:src/css/properties/margin_padding.rs" = 105
 
 [bun_install]
 "defaulted_failure:src/install/npm.rs" = 1

scripts/build/codegen.ts

@@ -308,6 +308,7 @@ export function emitCodegen(n: Ninja, cfg: Config, sources: Sources): CodegenOut
   emitBindgen(ctx);
   emitJsSink(ctx);
   emitObjectLuts(ctx);
+  emitCompressedEmbeds(ctx);
 
   n.phony("codegen", o.all);
   n.blank();
@@ -419,6 +420,50 @@ function emitBunError({ n, cfg, sources, o, dirStamp }: Ctx): void {
   o.rustInputs.push(...outputs);
 }
 
+/**
+ * zstd-compressed twins of assets that Bun never executes or parses itself —
+ * the shell completion scripts and the JS/CSS bundles that are only ever
+ * shipped to a browser (dev-server client runtime, error overlay, error page).
+ * Release builds embed these via `bun_zstd::embed_compressed!` and inflate on
+ * first use instead of carrying the plain text in `.rodata`. Anything that runs
+ * inside Bun (builtin modules, bake.server.js, FFI headers, …) stays as-is.
+ * Output: `<codegenDir>/compressed/<name>.zst`.
+ */
+function emitCompressedEmbeds({ n, cfg, o, dirStamp }: Ctx): void {
+  const script = resolve(cfg.cwd, "src", "codegen", "compress-embed.ts");
+  const assets: { input: string; name: string }[] = [
+    // Repo files, named by repo-relative path.
+    ...[
+      "completions/bun.bash",
+      "completions/bun.zsh",
+      "completions/bun.fish",
+      "src/runtime/bake/bun-framework-react/client.tsx",
+    ].map(rel => ({ input: resolve(cfg.cwd, rel), name: rel })),
+    // Codegen outputs (browser bundles), named `codegen/<path in codegenDir>`.
+    ...[
+      "bake.client.js",
+      "bake.error.js",
+      "bun-error/index.js",
+      "bun-error/bun-error.css",
+      "node-fallbacks/react-refresh.js",
+    ].map(rel => ({ input: resolve(cfg.codegenDir, rel), name: `codegen/${rel}` })),
+  ];
+  for (const { input, name } of assets) {
+    const out = resolve(cfg.codegenDir, "compressed", `${name}.zst`);
+    n.build({
+      outputs: [out],
+      rule: "codegen",
+      inputs: [script, input],
+      orderOnlyInputs: [dirStamp],
+      vars: { cwd: cfg.cwd, desc: `compressed/${name}.zst`, args: shJoin(cfg, ["run", script, input, out]) },
+    });
+    o.all.push(out);
+    // Debug reads the originals at runtime; only release embeds these.
+    if (cfg.debug) o.rustOrderOnly.push(out);
+    else o.rustInputs.push(out);
+  }
+}
+
 function emitRuntimeJs({ n, cfg, o, dirStamp }: Ctx): void {
   const src = resolve(cfg.cwd, "src", "runtime.bun.js");
   const out = resolve(cfg.codegenDir, "runtime.out.js");

src/ast/lib.rs

@@ -2049,13 +2049,24 @@ impl Log {
         })
     }
 
-    #[cold]
+    #[inline]
     pub fn add_range_error_with_notes(
         &mut self,
         source: Option<&Source>,
         r: Range,
         text: impl IntoText,
         notes: Box<[Data]>,
+    ) {
+        self.add_range_error_with_notes_text(source, r, text.into_text(), notes)
+    }
+
+    #[cold]
+    fn add_range_error_with_notes_text(
+        &mut self,
+        source: Option<&Source>,
+        r: Range,
+        text: Cow<'static, [u8]>,
+        notes: Box<[Data]>,
     ) {
         self.errors += 1;
         let data = self.tracked_range_data(source, r, text);
@@ -2071,8 +2082,15 @@ impl Log {
         self.msgs.push(msg);
     }
 
+    /// Generic only over the text conversion; the body is shared so each
+    /// `&[u8; N]` literal length does not get its own copy.
+    #[inline]
+    pub fn add_error(&mut self, source: Option<&Source>, loc: Loc, text: impl IntoText) {
+        self.add_error_text(source, loc, text.into_text());
+    }
+
     #[cold]
-    pub fn add_error(&mut self, _source: Option<&Source>, loc: Loc, text: impl IntoText) {
+    fn add_error_text(&mut self, _source: Option<&Source>, loc: Loc, text: Cow<'static, [u8]>) {
         self.errors += 1;
         let data = self.tracked_range_data(
             _source,
@@ -2768,9 +2786,14 @@ impl Source {
     }
 }
 
+#[inline]
 pub fn range_data(source: Option<&Source>, r: Range, text: impl IntoText) -> Data {
+    range_data_text(source, r, text.into_text())
+}
+
+fn range_data_text(source: Option<&Source>, r: Range, text: Cow<'static, [u8]>) -> Data {
     Data {
-        text: text.into_text(),
+        text,
         location: Location::init_or_null(source, r),
     }
 }