fix(bundler-plugins): Inject debug IDs into every esbuild rebuild (#26099)

The esbuild plugin cleared its set of wrapped entry points in `setup`,
which esbuild runs once per context. On `context().rebuild()` and in
watch mode, every entry point after the first build counted as already
wrapped, so the rebuilt bundles carried no debug ID and the upload
warned that no source maps were found. The reset now runs in an
`onStart` hook, once per build.

Found while reviewing #25648, where the
missing debug IDs also kept the plugin from cleaning up the maps it had
turned on.

Fixes #26098

Author: timfish

packages/bundler-plugins/src/esbuild/index.ts

@@ -67,6 +67,7 @@ interface EsbuildPluginBuild {
     options: { filter: RegExp },
     callback: (args: EsbuildOnResolveArgs) => EsbuildOnResolveResult | undefined,
   ) => void;
+  onStart: (callback: () => void) => void;
   onEnd: (callback: (result: EsbuildOnEndArgs) => void | Promise<void>) => void;
 }
 
@@ -156,7 +157,7 @@ export function sentryEsbuildPlugin(userOptions: Options = {}): any {
 
   return {
     name: pluginName,
-    setup({ initialOptions, onLoad, onResolve, onEnd }: EsbuildPluginBuild) {
+    setup({ initialOptions, onLoad, onResolve, onStart, onEnd }: EsbuildPluginBuild) {
       // Release and/or metadata injection
       if (!staticInjectionCode.isEmpty()) {
         const virtualInjectionFilePath = path.resolve('_sentry-injection-stub');
@@ -194,8 +195,9 @@ export function sentryEsbuildPlugin(userOptions: Options = {}): any {
 
       // Debug ID injection - requires per-entry-point unique IDs
       if (sourcemapsEnabled) {
-        // Clear state from previous builds (important for watch mode and test suites)
-        debugIdWrappedPaths.clear();
+        // `setup` runs once per context, `onStart` once per build, so a
+        // rebuild wraps the entry points again.
+        onStart(() => debugIdWrappedPaths.clear());
 
         if (!initialOptions.bundle) {
           logger.warn(

packages/bundler-plugins/test/esbuild/rebuild.test.ts

@@ -0,0 +1,57 @@
+import * as fs from 'fs';
+import * as os from 'os';
+import * as path from 'path';
+import * as esbuild from 'esbuild';
+import { describe, it, expect, beforeEach, afterEach } from 'vitest';
+import { sentryEsbuildPlugin } from '../../src/esbuild';
+
+const DEBUG_ID_MARKER = /sentry-dbid-([0-9a-f-]{36})/;
+
+describe('rebuilds', () => {
+  let tmpDir: string;
+  let entry: string;
+  let outDir: string;
+
+  beforeEach(() => {
+    tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'sentry-esbuild-rebuild-'));
+    entry = path.join(tmpDir, 'entry.js');
+    outDir = path.join(tmpDir, 'dist');
+    fs.writeFileSync(entry, 'export const answer = 42;\nconsole.log(answer);\n');
+  });
+
+  afterEach(() => {
+    fs.rmSync(tmpDir, { recursive: true, force: true });
+  });
+
+  function readDebugIds(): { bundle: string | undefined; map: unknown } {
+    const bundle = fs.readFileSync(path.join(outDir, 'entry.js'), 'utf8');
+    const map = JSON.parse(fs.readFileSync(path.join(outDir, 'entry.js.map'), 'utf8'));
+    return { bundle: bundle.match(DEBUG_ID_MARKER)?.[1], map: map.debug_id };
+  }
+
+  it('injects a debug ID into every rebuild of a context', async () => {
+    const context = await esbuild.context({
+      entryPoints: [entry],
+      bundle: true,
+      sourcemap: true,
+      outdir: outDir,
+      absWorkingDir: tmpDir,
+      plugins: [sentryEsbuildPlugin({ telemetry: false, sourcemaps: { disable: 'disable-upload' } })],
+    });
+
+    try {
+      await context.rebuild();
+      const first = readDebugIds();
+      expect(first.bundle).toBeDefined();
+      expect(first.map).toBe(first.bundle);
+
+      fs.writeFileSync(entry, 'export const answer = 43;\nconsole.log(answer);\n');
+      await context.rebuild();
+      const second = readDebugIds();
+      expect(second.bundle).toBeDefined();
+      expect(second.map).toBe(second.bundle);
+    } finally {
+      await context.dispose();
+    }
+  });
+});