fix: wire --bazel-maven-repo flag for custom WORKSPACE hubs and fix empty show_extension fallback

Bug 1: Legacy WORKSPACE projects with non-conventional maven_install names
(e.g. maven_legacy_app) were no longer discovered because the CLI never
exposed --bazel-maven-repo to pass extraMavenRepoNames. Add the flag to
cmd-manifest-bazel.mts, support it in socket.json defaults, and plumb it
through the auto-manifest pathway.

Bug 2: When bazel mod show_extension exits 0 but parseShowExtensionOutput
returns no hub names (format mismatch or empty report), discovery skipped
the conventional probe fallback. Now showExtensionSucceeded is only set
when parsed hubs are non-empty, so the conventional names are still probed.

Author: cursoragent

src/commands/manifest/bazel/cmd-manifest-bazel.mts

@@ -51,6 +51,12 @@ const config: CliCommandConfig = {
       description:
         'Flags forwarded to every bazel invocation (single quoted string)',
     },
+    bazelMavenRepo: {
+      type: 'string',
+      isMultiple: true,
+      description:
+        'Extra Maven hub repo name(s) to probe; repeatable. Use for legacy WORKSPACE projects whose maven_install uses a non-conventional name.',
+    },
     bazelOutputBase: {
       type: 'string',
       description: 'Bazel --output_base for read-only-cache CI environments',
@@ -202,7 +208,7 @@ async function run(
     sockJson?.defaults?.manifest?.bazel,
   )
 
-  const { ecosystem } = cli.flags
+  const { bazelMavenRepo, ecosystem } = cli.flags
   let { bazel, bazelFlags, bazelOutputBase, bazelRc, out, verbose } = cli.flags
 
   // Set defaults for any flag/arg that is not given. Check socket.json first.
@@ -260,6 +266,12 @@ async function run(
     }
   }
 
+  // Compose extra Maven repo names from the CLI flag and socket.json defaults.
+  const extraMavenRepoNames: string[] = [
+    ...(Array.isArray(bazelMavenRepo) ? bazelMavenRepo : []),
+    ...(sockJson.defaults?.manifest?.bazel?.bazelMavenRepo ?? []),
+  ].filter(Boolean)
+
   if (verbose) {
     logger.group('- ', parentName, config.commandName, ':')
     logger.group('- flags:', cli.flags)
@@ -318,6 +330,9 @@ async function run(
         bazelRc: bazelRc as string | undefined,
         bin: bazel as string | undefined,
         cwd,
+        extraMavenRepoNames: extraMavenRepoNames.length
+          ? extraMavenRepoNames
+          : undefined,
         ignoreDirNames: BAZEL_WALKER_IGNORE_DIR_NAMES,
         ignoreDirPrefixes: BAZEL_WALKER_IGNORE_DIR_PREFIXES,
         out: out as string,

src/commands/manifest/bazel/extract_bazel_to_maven.mts

@@ -260,8 +260,12 @@ async function discoverCandidatesForWorkspace(
   if (mode.bzlmod) {
     const extResult = await runBazelModShowMavenExtension(queryOpts)
     if (extResult.code === 0) {
-      candidates.push(...parseShowExtensionOutput(extResult.stdout))
-      showExtensionSucceeded = true
+      const parsedHubs = parseShowExtensionOutput(extResult.stdout)
+      candidates.push(...parsedHubs)
+      // Only consider successful when hubs were actually parsed; a zero
+      // exit with no recognized hub names (format mismatch, empty report)
+      // should still fall back to conventional probing.
+      showExtensionSucceeded = parsedHubs.length > 0
       if (verbose) {
         logger.log(
           `[VERBOSE] workspace ${workspaceRoot}: show_extension yielded`,

src/commands/manifest/generate_auto_manifest.mts

@@ -129,6 +129,7 @@ export async function generateAutoManifest({
       bazelRc: bazelConfig?.bazelRc,
       bin: bazelConfig?.bazel ?? bazelConfig?.bin,
       cwd,
+      extraMavenRepoNames: bazelConfig?.bazelMavenRepo,
       out: bazelConfig?.out ?? cwd,
       outLayout: 'flat',
       verbose: Boolean(bazelConfig?.verbose) || verbose,

src/utils/socket-json.mts

@@ -42,6 +42,7 @@ export interface SocketJson {
       bazel?: {
         bazel?: string | undefined
         bazelFlags?: string | undefined
+        bazelMavenRepo?: string[] | undefined
         bazelOutputBase?: string | undefined
         bazelRc?: string | undefined
         bin?: string | undefined