Add step in CI to upload link metadata (#25448)

### What does this PR do?

### How did you verify your code works?

---------

Co-authored-by: Claude <noreply@anthropic.com>

cmake/targets/BuildBun.cmake

@@ -1200,6 +1200,28 @@ set_target_properties(${bun} PROPERTIES LINK_DEPENDS ${BUN_SYMBOLS_PATH})
 
 include(SetupWebKit)
 
+if(BUN_LINK_ONLY)
+  register_command(
+    TARGET
+      ${bun}
+    TARGET_PHASE
+      POST_BUILD
+    COMMENT
+      "Uploading link metadata"
+    COMMAND
+      ${CMAKE_COMMAND} -E env
+        WEBKIT_DOWNLOAD_URL=${WEBKIT_DOWNLOAD_URL}
+        WEBKIT_VERSION=${WEBKIT_VERSION}
+        ZIG_COMMIT=${ZIG_COMMIT}
+        ${BUN_EXECUTABLE} ${CWD}/scripts/create-link-metadata.mjs ${BUILD_PATH} ${bun}
+    SOURCES
+      ${BUN_ZIG_OUTPUT}
+      ${BUN_CPP_OUTPUT}
+    ARTIFACTS
+      ${BUILD_PATH}/link-metadata.json
+  )
+endif()
+
 if(WIN32)
   if(DEBUG)
     target_link_libraries(${bun} PRIVATE

rust-toolchain.toml

@@ -0,0 +1,2 @@
+[toolchain]
+channel = "nightly-2025-12-10"

scripts/bootstrap.sh

@@ -1,5 +1,5 @@
 #!/bin/sh
-# Version: 21
+# Version: 24
 
 # A script that installs the dependencies needed to build and test Bun.
 # This should work on macOS and Linux with a POSIX shell.
@@ -1155,23 +1155,22 @@ llvm_version() {
 install_llvm() {
 	case "$pm" in
 	apt)
+		# Debian 13 (Trixie) has LLVM 19 natively, and apt.llvm.org doesn't have a trixie repo
+		if [ "$distro" = "debian" ]; then
+			install_packages \
+				"llvm-$(llvm_version)" \
+				"clang-$(llvm_version)" \
+				"lld-$(llvm_version)" \
+				"llvm-$(llvm_version)-dev" \
+				"llvm-$(llvm_version)-tools"
+		else
 			bash="$(require bash)"
 			llvm_script="$(download_file "https://apt.llvm.org/llvm.sh")"
-
-		# Debian trixie and newer don't have their own LLVM apt repo, use unstable
-		llvm_codename_arg=""
-		if [ "$distro" = "debian" ]; then
-			case "$VERSION_CODENAME" in
-			trixie|forky)
-				llvm_codename_arg="-n=unstable"
-				;;
-			esac
-		fi
-
-		execute_sudo "$bash" "$llvm_script" "$(llvm_version)" all $llvm_codename_arg
+			execute_sudo "$bash" "$llvm_script" "$(llvm_version)" all
 
 			# Install llvm-symbolizer explicitly to ensure it's available for ASAN
 			install_packages "llvm-$(llvm_version)-tools"
+		fi
 		;;
 	brew)
 		install_packages "llvm@$(llvm_version)"
@@ -1308,11 +1307,6 @@ install_sccache() {
 
 install_rust() {
 	case "$distro" in
-	alpine)
-		install_packages \
-			rust \
-			cargo
-		;;
 	freebsd)
 		install_packages lang/rust
 		create_directory "$HOME/.cargo/bin"
@@ -1328,6 +1322,9 @@ install_rust() {
 		rustup_script=$(download_file "https://sh.rustup.rs")
 		execute "$sh" -lc "$rustup_script -y --no-modify-path"
 		append_to_path "$rust_home/bin"
+
+		# Ensure all rustup files are accessible (for CI builds where different users run builds)
+		grant_to_user "$rust_home"
 		;;
 	esac
 

scripts/create-link-metadata.mjs

@@ -0,0 +1,49 @@
+#!/usr/bin/env bun
+/**
+ * Creates link-metadata.json with link command and build metadata
+ *
+ * Usage: bun scripts/create-link-metadata.mjs <build-path> <bun-target>
+ */
+
+import { $ } from "bun";
+import { dirname, join } from "path";
+
+const [buildPath, bunTarget] = process.argv.slice(2);
+
+if (!buildPath || !bunTarget) {
+  console.error("Usage: bun scripts/create-link-metadata.mjs <build-path> <bun-target>");
+  process.exit(1);
+}
+
+// Get the repo root (parent of scripts directory)
+const repoRoot = dirname(import.meta.dir);
+
+// Extract link command using ninja
+console.log("Extracting link command...");
+const linkCommandResult = await $`ninja -C ${buildPath} -t commands ${bunTarget}`.quiet();
+const linkCommand = linkCommandResult.stdout.toString().trim();
+
+// Read linker-related files from src/
+console.log("Reading linker files...");
+const linkerLds = await Bun.file(join(repoRoot, "src", "linker.lds")).text();
+const symbolsDyn = await Bun.file(join(repoRoot, "src", "symbols.dyn")).text();
+const symbolsTxt = await Bun.file(join(repoRoot, "src", "symbols.txt")).text();
+
+// Create metadata JSON with link command included
+const metadata = {
+  webkit_url: process.env.WEBKIT_DOWNLOAD_URL || "",
+  webkit_version: process.env.WEBKIT_VERSION || "",
+  zig_commit: process.env.ZIG_COMMIT || "",
+  target: bunTarget,
+  timestamp: new Date().toISOString(),
+  link_command: linkCommand,
+  linker_lds: linkerLds,
+  symbols_dyn: symbolsDyn,
+  symbols_txt: symbolsTxt,
+};
+
+const metadataPath = join(buildPath, "link-metadata.json");
+await Bun.write(metadataPath, JSON.stringify(metadata, null, 2));
+console.log(`Written to ${metadataPath}`);
+
+console.log("Done");