Address CodeRabbit review comments for publishConfig.directory

- Fixed --dry-run crash by passing edited_package.json.len instead of 0
  when publishConfig.directory is set (addresses comment #2427922588)

- Refactored pack_dir_path to be computed once and reused throughout
  the function, eliminating duplicate computation (addresses comment
  #2428128412)

- Added 3 additional test cases (addresses comment #2428128423):
  1. Verifies lifecycle scripts run from workspace root, not subdirectory
  2. Rejects parent directory traversal (../)
  3. Rejects absolute paths

- Added validation to reject invalid publishConfig.directory values:
  * Absolute paths are rejected with clear error message
  * Parent directory traversal (..) is rejected with clear error message
  * Added Output.flush() calls to ensure error messages are displayed

All 9 publishConfig.directory tests now passing.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/cli/pack_command.zig

@@ -1176,6 +1176,20 @@ pub const PackCommand = struct {
 
         // If publishConfig.directory is set, re-read package.json from that directory
         const actual_package_json_path: stringZ = if (publish_config_directory) |directory| path_with_dir: {
+            // Reject absolute paths before normalization
+            if (std.fs.path.isAbsolute(directory)) {
+                Output.errGeneric("publishConfig.directory cannot be an absolute path: {s}", .{directory});
+                Output.flush();
+                Global.crash();
+            }
+
+            // Reject parent directory traversal before normalization
+            if (strings.contains(directory, "..")) {
+                Output.errGeneric("publishConfig.directory cannot contain '..': {s}", .{directory});
+                Output.flush();
+                Global.crash();
+            }
+
             var path_buf: PathBuffer = undefined;
             const normalized_dir = strings.withoutTrailingSlash(strings.withoutPrefixComptime(
                 bun.path.normalizeBuf(directory, &path_buf, .posix),
@@ -1198,6 +1212,11 @@ pub const PackCommand = struct {
             );
         } else abs_package_json_path;
 
+        // Directory we actually pack from (directory containing actual package.json)
+        const pack_dir_path: string = strings.withoutTrailingSlash(
+            strings.withoutSuffixComptime(actual_package_json_path, "package.json"),
+        );
+
         // Re-read package.json from the actual directory
         const actual_json = if (publish_config_directory != null) switch (manager.workspace_package_json_cache.getWithPath(manager.allocator, manager.log, actual_package_json_path, .{
             .guess_indentation = true,
@@ -1368,7 +1387,6 @@ pub const PackCommand = struct {
         };
 
         // Open the directory where files will be packed from (and where package.json is)
-        const pack_dir_path: string = strings.withoutTrailingSlash(strings.withoutSuffixComptime(actual_package_json_path, "package.json"));
         var root_dir = root_dir: {
             var path_buf: PathBuffer = undefined;
             @memcpy(path_buf[0..pack_dir_path.len], pack_dir_path);

test/cli/install/bun-pack.test.ts

@@ -1546,4 +1546,71 @@ describe("publishConfig.directory", () => {
     // Should not create the tarball
     expect(await exists(join(packageDir, "pack-publishconfig-dryrun-1.0.0.tgz"))).toBeFalse();
   });
+
+  test("scripts run from workspace root", async () => {
+    await mkdir(join(packageDir, "dist"), { recursive: true });
+    await Promise.all([
+      write(
+        join(packageDir, "package.json"),
+        JSON.stringify({
+          name: "pack-publishconfig-scripts",
+          version: "1.0.0",
+          scripts: {
+            prepack: "touch .prepack-touched",
+          },
+          publishConfig: {
+            directory: "dist",
+          },
+        }),
+      ),
+      write(
+        join(packageDir, "dist", "package.json"),
+        JSON.stringify({
+          name: "pack-publishconfig-scripts",
+          version: "1.0.0",
+        }),
+      ),
+      write(join(packageDir, "dist", "index.js"), "console.log('dist');"),
+    ]);
+
+    await pack(packageDir, bunEnv);
+
+    // Script should run from workspace root, not from dist/
+    expect(await exists(join(packageDir, ".prepack-touched"))).toBeTrue();
+    expect(await exists(join(packageDir, "dist", ".prepack-touched"))).toBeFalse();
+  });
+
+  test("rejects parent directory traversal", async () => {
+    await write(
+      join(packageDir, "package.json"),
+      JSON.stringify({
+        name: "pack-publishconfig-parent",
+        version: "1.0.0",
+        publishConfig: {
+          directory: "../outside",
+        },
+      }),
+    );
+
+    const { err } = await packExpectError(packageDir, bunEnv);
+    // Should reject parent directory traversal
+    expect(err).toContain("publishConfig.directory cannot contain '..'");
+  });
+
+  test("rejects absolute paths", async () => {
+    await write(
+      join(packageDir, "package.json"),
+      JSON.stringify({
+        name: "pack-publishconfig-absolute",
+        version: "1.0.0",
+        publishConfig: {
+          directory: "/tmp/absolute",
+        },
+      }),
+    );
+
+    const { err } = await packExpectError(packageDir, bunEnv);
+    // Should reject absolute paths
+    expect(err).toContain("publishConfig.directory cannot be an absolute path");
+  });
 });