fix: suppress stdout pollution in create_task_worktree (t169, t173)

.agents/scripts/supervisor-helper.sh

@@ -2680,13 +2680,14 @@ create_task_worktree() {
     if [[ "$needs_cleanup" == "true" ]]; then
         # Remove worktree if it exists
         if [[ -d "$worktree_path" ]]; then
-            git -C "$repo" worktree remove "$worktree_path" --force 2>/dev/null || rm -rf "$worktree_path"
-            git -C "$repo" worktree prune 2>/dev/null || true
+            git -C "$repo" worktree remove "$worktree_path" --force &>/dev/null || rm -rf "$worktree_path"
+            git -C "$repo" worktree prune &>/dev/null || true
         fi
-        # Delete local branch
-        git -C "$repo" branch -D "$branch_name" 2>/dev/null || true
+        # Delete local branch — MUST suppress stdout (outputs "Deleted branch ...")
+        # which would pollute the function's return value captured by $()
+        git -C "$repo" branch -D "$branch_name" &>/dev/null || true
         # Delete remote branch (best-effort, don't fail if remote is gone)
-        git -C "$repo" push origin --delete "$branch_name" 2>/dev/null || true
+        git -C "$repo" push origin --delete "$branch_name" &>/dev/null || true
     fi
 
     # Try wt first (redirect its verbose output to stderr)
@@ -3050,6 +3051,15 @@ cmd_dispatch() {
         return 1
     }
 
+    # Validate worktree path is an actual directory (guards against stdout
+    # pollution from git commands inside create_task_worktree)
+    if [[ ! -d "$worktree_path" ]]; then
+        log_error "Worktree path is not a directory: '$worktree_path'"
+        log_error "This usually means a git command leaked stdout into the path variable"
+        cmd_transition "$task_id" "failed" --error "Worktree path invalid: $worktree_path"
+        return 1
+    fi
+
     local branch_name="feature/${task_id}"
 
     # Set up log file

tests/test-supervisor-state-machine.sh

@@ -992,6 +992,68 @@ else
     fail "Exit 0 with error strings should NOT be blocked" "Got: $eval_result"
 fi
 
+# ============================================================
+# SECTION 7: Worktree Path Integrity
+# ============================================================
+section "Worktree Path Integrity"
+
+# Test: create_task_worktree returns a clean single-line path (no stdout pollution)
+# This is a regression test for the bug where `git branch -D` output ("Deleted branch ...")
+# leaked into the function's return value, causing dispatch to fail with invalid paths.
+
+WORKTREE_TEST_DIR=$(mktemp -d)
+WORKTREE_TEST_REPO="$WORKTREE_TEST_DIR/test-repo"
+trap 'rm -rf "$WORKTREE_TEST_DIR"; rm -rf "$TEST_DIR"' EXIT
+
+# Set up a minimal git repo for worktree testing
+git init "$WORKTREE_TEST_REPO" &>/dev/null
+git -C "$WORKTREE_TEST_REPO" commit --allow-empty -m "initial" &>/dev/null
+
+# Create a branch that will need cleanup (simulates stale branch from prior failed dispatch)
+git -C "$WORKTREE_TEST_REPO" branch "feature/wt-test-001" &>/dev/null
+
+# Add task to supervisor DB
+sup add wt-test-001 --repo "$WORKTREE_TEST_REPO" --description "Worktree stdout leak test" >/dev/null 2>&1 || true
+
+# Call create_task_worktree directly. The script calls main "$@" at the bottom
+# when sourced, so we pass "init" to avoid show_usage. We redirect the source's
+# stdout to /dev/null (suppresses cmd_init output) — function definitions still
+# register in the current shell. Then we call the function we want to test.
+worktree_output=$(bash -c "
+    export AIDEVOPS_SUPERVISOR_DIR='$TEST_DIR'
+    set -- init
+    source '$SUPERVISOR_SCRIPT' >/dev/null
+    create_task_worktree 'wt-test-001' '$WORKTREE_TEST_REPO' true
+" 2>/dev/null)
+
+# Count lines — should be exactly 1 (the path)
+line_count=$(echo "$worktree_output" | wc -l | tr -d ' ')
+if [[ "$line_count" -eq 1 ]]; then
+    pass "create_task_worktree returns exactly 1 line (no stdout pollution)"
+else
+    fail "create_task_worktree returned $line_count lines (stdout pollution detected)" \
+        "Output: $(echo "$worktree_output" | head -3)"
+fi
+
+# Verify the returned path is a real directory
+if [[ -d "$worktree_output" ]]; then
+    pass "create_task_worktree returns a valid directory path"
+else
+    fail "create_task_worktree path is not a directory" "Got: '$worktree_output'"
+fi
+
+# Verify path doesn't contain "Deleted branch" (the specific pollution we fixed)
+if echo "$worktree_output" | grep -qi "deleted branch"; then
+    fail "create_task_worktree output contains 'Deleted branch' pollution" \
+        "Got: '$worktree_output'"
+else
+    pass "create_task_worktree output is free of 'Deleted branch' pollution"
+fi
+
+# Clean up the test worktree
+git -C "$WORKTREE_TEST_REPO" worktree remove "$worktree_output" --force &>/dev/null || rm -rf "$worktree_output"
+git -C "$WORKTREE_TEST_REPO" worktree prune &>/dev/null || true
+
 # ============================================================
 # SUMMARY
 # ============================================================