🤖 fix: dedupe migrated background bash IDs

Change-Id: I4fe6af0fe450b12528335bbb04310dbe37d866cf
Signed-off-by: Thomas Kosiewski <tk@coder.com>

Author: ThomasK33

src/node/services/backgroundProcessManager.ts

@@ -1,5 +1,6 @@
 import type { Runtime, BackgroundHandle } from "@/node/runtime/Runtime";
 import { spawnProcess } from "./backgroundProcessExecutor";
+import assert from "@/common/utils/assert";
 import { getErrorMessage } from "@/common/utils/errors";
 import { log } from "./log";
 import { AsyncMutex } from "@/node/utils/concurrency/asyncMutex";
@@ -144,6 +145,30 @@ export class BackgroundProcessManager extends EventEmitter<BackgroundProcessMana
     return this.bgOutputDir;
   }
 
+  /**
+   * Generate a unique background process ID.
+   *
+   * Background process IDs are used as tool-visible identifiers (e.g. task_await with bash: IDs),
+   * so they must be globally unique across all running processes.
+   *
+   * If the base ID is already in use, we append " (1)", " (2)", etc.
+   */
+  generateUniqueProcessId(baseId: string): string {
+    assert(
+      typeof baseId === "string" && baseId.length > 0,
+      "BackgroundProcessManager.generateUniqueProcessId requires a non-empty baseId"
+    );
+
+    let processId = baseId;
+    let suffix = 1;
+    while (this.processes.has(processId)) {
+      processId = `${baseId} (${suffix})`;
+      suffix++;
+    }
+
+    return processId;
+  }
+
   /**
    * Spawn a new process with background-style infrastructure.
    *
@@ -175,13 +200,7 @@ export class BackgroundProcessManager extends EventEmitter<BackgroundProcessMana
   > {
     log.debug(`BackgroundProcessManager.spawn() called for workspace ${workspaceId}`);
 
-    // Generate unique processId, appending (1), (2), etc. on collision
-    let processId = config.displayName;
-    let suffix = 1;
-    while (this.processes.has(processId)) {
-      processId = `${config.displayName} (${suffix})`;
-      suffix++;
-    }
+    const processId = this.generateUniqueProcessId(config.displayName);
 
     // Spawn via executor with background infrastructure
     // spawnProcess uses runtime.tempDir() internally for output directory

src/node/services/tools/bash.ts

@@ -616,7 +616,8 @@ ${script}`;
 
           // Migrate to background tracking if manager is available
           if (config.backgroundProcessManager && config.workspaceId) {
-            const processId = safeDisplayName;
+            const processId =
+              config.backgroundProcessManager.generateUniqueProcessId(safeDisplayName);
 
             // Create a synthetic ExecStream for the migration streams
             // The UI streams are still being consumed, migration streams continue to files
@@ -647,7 +648,8 @@ ${script}`;
                 processId,
                 config.workspaceId,
                 script,
-                migrateResult.outputDir
+                migrateResult.outputDir,
+                safeDisplayName
               );
 
               return {