Add gh-aw agentic workflow for upgrading Python libraries (#7117)

* Add gh-aw agentic workflow for upgrading Python libraries

- upgrade-pylib.md: Claude-based workflow triggered via workflow_dispatch
- Runs `scripts/update_lib quick <name>` to sync a library from CPython
- Creates a PR with the result, referencing issue #6839

.gitattributes

@@ -66,3 +66,5 @@ Lib/test/certdata/*.0                               generated
 Lib/test/levenshtein_examples.json                  generated
 Lib/test/test_stable_abi_ctypes.py                  generated
 Lib/token.py                                        generated
+
+.github/workflows/*.lock.yml linguist-generated=true merge=ours

.github/aw/actions-lock.json

@@ -0,0 +1,14 @@
+{
+  "entries": {
+    "actions/github-script@v8": {
+      "repo": "actions/github-script",
+      "version": "v8",
+      "sha": "ed597411d8f924073f98dfc5c65a23a2325f34cd"
+    },
+    "github/gh-aw/actions/setup@v0.43.22": {
+      "repo": "github/gh-aw/actions/setup",
+      "version": "v0.43.22",
+      "sha": "fe858c3e14589bf396594a0b106e634d9065823e"
+    }
+  }
+}

.github/workflows/upgrade-pylib.md

@@ -0,0 +1,122 @@
+---
+description: |
+  Pick an out-of-sync Python library from the todo list and upgrade it
+  by running `scripts/update_lib quick`, then open a pull request.
+
+on:
+  workflow_dispatch:
+    inputs:
+      name:
+        description: "Module name to upgrade (leave empty to auto-pick)"
+        required: false
+        type: string
+
+timeout-minutes: 45
+
+permissions:
+  contents: read
+  issues: read
+  pull-requests: read
+
+network:
+  allowed:
+    - defaults
+    - rust
+    - python
+
+engine: claude
+
+runtimes:
+  python:
+    version: "3.12"
+
+tools:
+  bash:
+    - ":*"
+  edit:
+  github:
+    toolsets: [repos, issues, pull_requests]
+    read-only: true
+
+safe-outputs:
+  create-pull-request:
+    title-prefix: "Update "
+    labels: [pylib-sync]
+    draft: false
+    expires: 30
+
+env:
+  PYTHON_VERSION: "v3.14.3"
+  ISSUE_ID: "6839"
+---
+
+# Upgrade Python Library
+
+You are an automated maintenance agent for RustPython, a Python 3 interpreter written in Rust. Your task is to upgrade one out-of-sync Python standard library module from CPython.
+
+## Step 1: Set up the environment
+
+Clone CPython at the correct version tag under the working directory:
+
+```bash
+git clone --depth 1 --branch "$PYTHON_VERSION" https://github.com/python/cpython.git cpython
+```
+
+## Step 2: Pick a module to upgrade
+
+If the user provided a module name via `${{ github.event.inputs.name }}`, use that module.
+
+Otherwise, run the todo script to find candidates:
+
+```bash
+python3 scripts/update_lib todo
+```
+
+From the output, pick **one** module that:
+- Is marked `[ ]` (not yet up-to-date)
+- Has `[no deps]` or `[0/N deps]` (all dependencies are satisfied)
+- Has a small diff count (`Δ` number) — prefer modules with smaller diffs for reliability
+- Is NOT one of these complex modules: `opcode`, `datetime`, `collections`, `random`, `hashlib`, `tokenize`, `pdb`, `_pyrepl`, `concurrent`, `asyncio`, `multiprocessing`, `ctypes`, `idlelib`, `tkinter`, `shutil`, `tarfile`, `email`, `unittest`
+
+## Step 3: Run the upgrade
+
+Run the quick upgrade command. This will copy the library from CPython, migrate test files preserving RustPython markers, auto-mark test failures, and create a git commit:
+
+```bash
+python3 scripts/update_lib quick <module_name>
+```
+
+This takes a while because it builds RustPython (`cargo build --release`) and runs tests to determine which ones pass or fail.
+
+If the command fails, report the error and stop. Do not try to fix Rust code or modify test files manually.
+
+## Step 4: Verify the result
+
+After the script succeeds, check what changed:
+
+```bash
+git log -1 --stat
+git diff HEAD~1 --stat
+```
+
+Make sure the commit was created with the correct message format: `Update <name> from <version>`.
+
+## Step 5: Create the pull request
+
+Create a pull request. Reference issue #${{ env.ISSUE_ID }} in the body but do **NOT** use keywords that auto-close issues (Fix, Close, Resolve).
+
+Use this format for the PR body:
+
+```
+## Summary
+
+Upgrade `<module_name>` from CPython $PYTHON_VERSION.
+
+Part of #$ISSUE_ID
+
+## Changes
+
+- Updated `Lib/<module_name>` from CPython
+- Migrated test files preserving RustPython markers
+- Auto-marked test failures with `@expectedFailure`
+```

crates/vm/src/stdlib/time.rs

@@ -939,7 +939,10 @@ mod decl {
 
     /// Extract fields from StructTimeData into a libc::tm for mktime.
     #[cfg(any(unix, windows))]
-    pub(super) fn tm_from_struct_time(t: &StructTimeData, vm: &VirtualMachine) -> PyResult<libc::tm> {
+    pub(super) fn tm_from_struct_time(
+        t: &StructTimeData,
+        vm: &VirtualMachine,
+    ) -> PyResult<libc::tm> {
         let invalid_tuple = || vm.new_type_error("mktime(): illegal time tuple argument");
         let year: i32 = t
             .tm_year
@@ -1002,9 +1005,7 @@ mod decl {
                 }
                 let secs = float.floor();
                 if secs < libc::time_t::MIN as f64 || secs > libc::time_t::MAX as f64 {
-                    return Err(
-                        vm.new_overflow_error("timestamp out of range for platform time_t")
-                    );
+                    return Err(vm.new_overflow_error("timestamp out of range for platform time_t"));
                 }
                 Ok(secs as libc::time_t)
             }