make local builds respect "ignore" files when uploading the built output

src/deploy/apphosting/prepare.spec.ts

@@ -24,6 +24,8 @@ import * as apphostingUtils from "../../apphosting/utils";
 import { AppHostingYamlConfig, EnvMap } from "../../apphosting/yaml";
 import { Options } from "../../options";
 import { AppHostingSingle } from "../../firebaseConfig";
+import * as fs from "fs";
+import * as fsAsync from "../../fsAsync";
 
 const BASE_OPTS = {
   cwd: "/",
@@ -88,6 +90,12 @@ describe("apphosting", () => {
     addServiceAccountToRolesStub = sinon
       .stub(resourceManager, "addServiceAccountToRoles")
       .resolves();
+
+    sinon.stub(fs, "existsSync").returns(false);
+    sinon.stub(fs, "mkdirSync").returns(undefined);
+    sinon.stub(fs, "rmSync").returns(undefined);
+    sinon.stub(fs, "copyFileSync").returns(undefined);
+    sinon.stub(fsAsync, "readdirRecursive").resolves([]);
   });
 
   afterEach(() => {

src/deploy/apphosting/prepare.ts

@@ -1,4 +1,7 @@
+import * as fs from "fs";
 import * as path from "path";
+import * as fsAsync from "../../fsAsync";
+import { resolveIgnorePatterns } from "./util";
 import {
   doSetupSourceDeploy,
   ensureAppHostingComputeServiceAccount,
@@ -192,10 +195,15 @@ export default async function (context: Context, options: Options): Promise<void
     );
     await injectAutoInitEnvVars(cfg, backends, buildEnv, runtimeEnv);
 
+    const rootDir = options.projectRoot || process.cwd();
+    const localBuildDir = path.join(rootDir, "local_build");
+
     try {
+      await prepareLocalBuildDirectory(rootDir, localBuildDir, cfg);
+
       const { outputFiles, annotations, buildConfig } = await localBuild(
         projectId,
-        options.projectRoot || "./",
+        localBuildDir,
         "nextjs",
         buildEnv[cfg.backendId] || {},
         {
@@ -377,3 +385,44 @@ async function ensureAppHostingServiceAgentRoles(
     );
   }
 }
+
+/**
+ * Prepares the directory for local builds by copying non-ignored files.
+ */
+async function prepareLocalBuildDirectory(
+  rootDir: string,
+  localBuildDir: string,
+  cfg: AppHostingSingle,
+): Promise<void> {
+  // Resolve ignores for local builds, skipping default node_modules ignore
+  const ignore = resolveIgnorePatterns(cfg, rootDir, /* skipDefaultNodeModules= */ true);
+  ignore.push("local_build"); // Always ignore the build directory itself
+
+  // Warn if node_modules is explicitly ignored
+  if (cfg.ignore?.includes("node_modules")) {
+    logLabeledWarning(
+      "apphosting",
+      `You have included 'node_modules' in your ignore list for local builds. This might cause the build to fail if dependencies are missing in the build directory.`,
+    );
+  }
+
+  // Create local_build dir
+  if (fs.existsSync(localBuildDir)) {
+    fs.rmSync(localBuildDir, { recursive: true, force: true });
+  }
+  fs.mkdirSync(localBuildDir, { recursive: true });
+
+  // Copy files respecting ignores
+  const filesToCopy = await fsAsync.readdirRecursive({
+    path: rootDir,
+    ignore: ignore,
+    isGitIgnore: true,
+  });
+
+  for (const file of filesToCopy) {
+    const relativePath = path.relative(rootDir, file.name);
+    const destPath = path.join(localBuildDir, relativePath);
+    fs.mkdirSync(path.dirname(destPath), { recursive: true });
+    fs.copyFileSync(file.name, destPath);
+  }
+}

src/deploy/apphosting/util.spec.ts

@@ -4,6 +4,7 @@ import * as path from "path";
 import * as tmp from "tmp";
 import * as tar from "tar";
 import * as util from "./util";
+import { AppHostingSingle } from "../../firebaseConfig";
 
 describe("util", () => {
   let tmpDir: tmp.DirResult;
@@ -78,5 +79,90 @@ describe("util", () => {
       expect(files).to.include("dist/index.js");
       expect(files).to.not.include("apphosting.yaml");
     });
+
+    it("should respect ignore patterns in config", async () => {
+      fs.writeFileSync(path.join(distDir, "index.js"), "console.log('hello')");
+      fs.writeFileSync(path.join(distDir, "ignored.txt"), "ignore me");
+
+      const config = {
+        backendId: "test-backend",
+        rootDir: "",
+        ignore: ["**/ignored.txt"],
+      };
+
+      const tarballPath: string = await util.createLocalBuildTarArchive(
+        config,
+        rootDir,
+        path.relative(rootDir, distDir),
+      );
+
+      const files: string[] = [];
+      tar.list({
+        file: tarballPath,
+        sync: true,
+        onentry: (entry: { path: string }) => files.push(entry.path),
+      });
+
+      expect(files).to.include("dist/index.js");
+      expect(files).to.not.include("dist/ignored.txt");
+    });
+
+    it("should use default ignores when config.ignore is missing", async () => {
+      fs.writeFileSync(path.join(distDir, "index.js"), "console.log('hello')");
+      const nodeModulesDir = path.join(distDir, "node_modules");
+      fs.mkdirSync(nodeModulesDir);
+      fs.writeFileSync(path.join(nodeModulesDir, "some-file.js"), "console.log('vendor')");
+
+      const configWithoutIgnore: AppHostingSingle = {
+        backendId: "test-backend",
+        rootDir: "",
+        ignore: undefined as unknown as string[],
+      };
+
+      const tarballPath: string = await util.createLocalBuildTarArchive(
+        // eslint-disable-next-line @typescript-eslint/no-unsafe-argument
+        configWithoutIgnore,
+        rootDir,
+        path.relative(rootDir, distDir),
+      );
+
+      const files: string[] = [];
+      tar.list({
+        file: tarballPath,
+        sync: true,
+        onentry: (entry: { path: string }) => files.push(entry.path),
+      });
+
+      expect(files).to.include("dist/index.js");
+      expect(files).to.not.include("dist/node_modules/some-file.js");
+    });
+
+    it("should respect .gitignore patterns", async () => {
+      fs.writeFileSync(path.join(distDir, "index.js"), "console.log('hello')");
+      fs.writeFileSync(path.join(distDir, "gitignored.txt"), "ignore me");
+      fs.writeFileSync(path.join(distDir, ".gitignore"), "gitignored.txt");
+
+      const config = {
+        backendId: "test-backend",
+        rootDir: "",
+        ignore: [],
+      };
+
+      const tarballPath: string = await util.createLocalBuildTarArchive(
+        config,
+        rootDir,
+        path.relative(rootDir, distDir),
+      );
+
+      const files: string[] = [];
+      tar.list({
+        file: tarballPath,
+        sync: true,
+        onentry: (entry: { path: string }) => files.push(entry.path),
+      });
+
+      expect(files).to.include("dist/index.js");
+      expect(files).to.not.include("dist/gitignored.txt");
+    });
   });
 });

src/deploy/apphosting/util.ts

@@ -28,7 +28,7 @@ export async function createLocalBuildTarArchive(
   const tmpFile = tmp.fileSync({ prefix: `${config.backendId}-`, postfix: ".tar.gz" }).name;
 
   const targetDir = targetSubDir ? path.join(rootDir, targetSubDir) : rootDir;
-  const ignore = ["firebase-debug.log", "firebase-debug.*.log", ".git"];
+  const ignore = resolveIgnorePatterns(config, targetDir);
   const rdrFiles = await fsAsync.readdirRecursive({
     path: targetDir,
     ignore: ignore,
@@ -90,10 +90,7 @@ export async function createSourceDeployArchive(
 
   const targetDir = targetSubDir ? path.join(rootDir, targetSubDir) : rootDir;
   // We must ignore firebase-debug.log or weird things happen if you're in the public dir when you deploy.
-  const ignore = config.ignore || ["node_modules", ".git"];
-  ignore.push("firebase-debug.log", "firebase-debug.*.log");
-  const gitIgnorePatterns = parseGitIgnorePatterns(targetDir);
-  ignore.push(...gitIgnorePatterns);
+  const ignore = resolveIgnorePatterns(config, targetDir);
   try {
     const files = await fsAsync.readdirRecursive({
       path: targetDir,
@@ -110,13 +107,33 @@ export async function createSourceDeployArchive(
     await pipeAsync(archive, fileStream);
   } catch (err: unknown) {
     throw new FirebaseError(
-      `Could not read source directory. Remove links and shortcuts and try again. Original: ${err}`,
+      `Could not read source directory. Remove links and shortcuts and try again. Original: ${String(err)}`,
       { original: err as Error, exit: 1 },
     );
   }
   return tmpFile;
 }
 
+/**
+ * Resolves the ignore patterns for App Hosting deployments.
+ * Merges config ignores, defaults, and .gitignore patterns.
+ */
+export function resolveIgnorePatterns(
+  config: AppHostingSingle,
+  targetDir: string,
+  skipDefaultNodeModules = false,
+): string[] {
+  const ignore = config.ignore
+    ? [...config.ignore]
+    : skipDefaultNodeModules
+      ? [".git"]
+      : ["node_modules", ".git"];
+  ignore.push("firebase-debug.log", "firebase-debug.*.log");
+  const gitIgnorePatterns = parseGitIgnorePatterns(targetDir);
+  ignore.push(...gitIgnorePatterns);
+  return ignore;
+}
+
 function parseGitIgnorePatterns(projectRoot: string, gitIgnorePath = ".gitignore"): string[] {
   const absoluteFilePath = path.resolve(projectRoot, gitIgnorePath);
   if (!fs.existsSync(absoluteFilePath)) {