repo_support: add a script that generates cherry pick PRs from main to a release branch, in correct merge order by mattkur · Pull Request #2680 · microsoft/openvmm

mattkur · 2026-01-22T23:33:56Z

Adds gen_cherrypick_prs.py, which cherry picks PRs that are completed into main into the release/<foo> branch.
The script generates these in merge order, and stops if there are merge conflicts.
You can specify a set of PRs to cherry pick, or the script will try to do any PRs that are missing.

Written with copilot.

Copilot

Pull request overview

This PR adds a Python script to automate the creation of cherry-pick PRs from the main branch to release branches. The script handles the complete workflow of finding merged PRs, cherry-picking them in merge order, and creating corresponding backport PRs on GitHub.

Changes:

Adds gen_cherrypick_prs.py script that generates cherry-pick PRs for release branches
Supports both manual PR specification and automatic discovery via backport labels
Includes conflict detection, duplicate backport checking, and interactive confirmation

Copilot · 2026-01-22T23:37:38Z

repo_support/gen_cherrypick_prs.py

+        queries.append(f'base:{base_branch} "{orig_title}" in:title')
+
+    items: List[dict] = []
+    seen_numbers: set[int] = set()


The type hint set[int] uses Python 3.9+ syntax. For better compatibility with older Python versions, consider using Set[int] from the typing module which is already imported on line 41.

Copilot · 2026-01-22T23:37:38Z

repo_support/gen_cherrypick_prs.py

+            return f"{orange}*IN PROGRESS*{reset}"
+        return "*NONE*"
+
+    backport_map: dict[int, List[BackportInfo]] = {}


The type hint dict[int, List[BackportInfo]] uses Python 3.9+ syntax. For consistency with the typing imports already present and better compatibility, consider using Dict[int, List[BackportInfo]] from the typing module.

Copilot · 2026-01-22T23:37:38Z

repo_support/gen_cherrypick_prs.py

+        stderr = getattr(p, "stderr", "") or ""
+        stdout = getattr(p, "stdout", "") or ""


The getattr() calls with fallback empty strings are unnecessary. When capture=True, subprocess.run with stdout=subprocess.PIPE and stderr=subprocess.PIPE always sets these attributes. The defensive coding here could mask programming errors.

Suggested change

stderr = getattr(p, "stderr", "") or ""

stdout = getattr(p, "stdout", "") or ""

stderr = p.stderr or ""

stdout = p.stdout or ""

Copilot · 2026-01-22T23:37:39Z

repo_support/gen_cherrypick_prs.py

+            seen_numbers.add(n)
+            items.append(pr)
+
+    rx = re.compile(rf"\bPR\s*#?{pr_number}\b", re.IGNORECASE)


The regex pattern doesn't escape the PR number, which could lead to false matches. For example, if searching for PR #123, the pattern \bPR\s*#?123\b would match "PR #1234" because \b matches between "123" and "4". Consider using a more precise pattern like rf"\bPR\s*#?{pr_number}(?:\b|$)" or ensuring the match is complete.

Suggested change

rx = re.compile(rf"\bPR\s*#?{pr_number}\b", re.IGNORECASE)

rx = re.compile(

rf"\bPR\s*#?{re.escape(str(pr_number))}(?:\b|$)", re.IGNORECASE

)

Copilot · 2026-01-22T23:37:39Z

repo_support/gen_cherrypick_prs.py

+        if not confirm("Create this PR on GitHub? [y/N] "):
+            print("Aborting by user request. No further PRs will be created.")
+            return 0


When the user confirms to not create a PR (line 586-588), the script returns 0 (success), but some PRs may still be unprocessed. This could be confusing. Consider returning a different exit code or providing a summary of skipped PRs to make it clear that not all PRs were processed.

Copilot · 2026-01-22T23:37:41Z

repo_support/gen_cherrypick_prs.py

+    green = "\x1b[32m"
+    orange = "\x1b[38;5;208m"
+    reset = "\x1b[0m"


The script uses ANSI color codes directly in the main function. These may not work correctly on all terminals (especially on Windows without ANSI support). Consider checking if the output is a TTY and/or if color is supported before using color codes, or using a library like colorama for cross-platform color support.

Copilot · 2026-01-22T23:37:41Z

repo_support/gen_cherrypick_prs.py

+        if not (
+            rx.search(hay)
+            or url_fragment in hay
+            or (title_lc and title_lc in title.lower())


The title matching on line 160 uses substring matching (title_lc in title.lower()), which could produce false positives. For example, if the original PR title is "Fix bug", it would match any PR with "Fix bug" anywhere in its title like "Fix bug in parser" even if that's a different PR. Consider using more precise matching or requiring the title match to be more substantial (e.g., checking for an exact match or a high similarity threshold).

repo_support/gen_cherrypick_prs.py

Copilot · 2026-01-22T23:37:41Z

repo_support/gen_cherrypick_prs.py

+        "--search",
+        query,
+        "--limit",
+        "50",


The gh pr list --limit 50 hardcoded limit in the search query might miss backport PRs if there are more than 50 matching PRs. This could lead to the script incorrectly thinking a PR hasn't been backported when it actually has. Consider increasing this limit or adding pagination to ensure all matching PRs are found.

Suggested change

"50",

"1000",

Copilot · 2026-01-22T23:37:42Z

repo_support/gen_cherrypick_prs.py

+        title = str(pr.get("title") or "")
+        body = str(pr.get("body") or "")
+        hay = f"{title}\n{body}"
+        hay_lc = hay.lower()


Variable hay_lc is not used.

Suggested change

hay_lc = hay.lower()

gurasinghMS · 2026-01-23T22:06:34Z

This looks great. Thanks for doing it!!
I'm wondering if git worktrees could be of some help here. I haven't played around with them a ton but this seems it could be a good fit. Instead of forcing a user to have a clean state we create 1 worktree per PR that needs to be created. That way if any of the commands were to fail for any unknown reason, failed state is isolated to the worktree.

gurasinghMS · 2026-01-23T22:21:16Z

repo_support/gen_cherrypick_prs.py

+    orange = "\x1b[38;5;208m"
+    reset = "\x1b[0m"
+
+    def status_label(state: str) -> str:


nit: Move this function outside of main

gurasinghMS · 2026-01-23T22:30:45Z

repo_support/gen_cherrypick_prs.py

+            prj = gh_pr_view(n, args.repo)
+
+            state = str(prj.get("state", "")).upper()
+            if state != "MERGED":


You could also have not_completed list being populated in this branch, instead of failing when it comes across an unmerged.
How about making a function that does that takes a list of pr jsons and spits out 2 lists: infos and not_completed. That way behavior remains consistent in both from_backport_label and by_pr_number branches.

gurasinghMS · 2026-01-23T23:04:43Z

repo_support/gen_cherrypick_prs.py

+    print("\nDone. Created PRs:")
+    for n, url in created:
+        print(f"  #{n}: {url}")
+


Add a checkout back to the branch this script was started from.

mattkur · 2026-02-04T17:36:09Z

@gurasinghMS : thank you for the good feedback! I'm not in a position to take it right now. So, let me know if you think this PR (now updated with minor changes) is "good enough" to be valuable.

…o a release branch, in correct merge order

alandau

The script works for me (with the PAT change), thanks!

alandau · 2026-02-12T20:54:26Z

repo_support/gen_cherrypick_prs.py

+        path = url[len("git@github.com:") :]
+    elif url.startswith("https://github.com/"):
+        path = url[len("https://github.com/") :]
+    else:


Can we add support for PAT GitHub auth?

Suggested change

else:

elif m := re.match(r"https://[\w:]+@github.com/", url):

path = url[m.end() :]

else:

mattkur requested a review from a team as a code owner January 22, 2026 23:33

Copilot AI review requested due to automatic review settings January 22, 2026 23:33

Copilot started reviewing on behalf of mattkur January 22, 2026 23:34 View session

Copilot AI reviewed Jan 22, 2026

View reviewed changes

gurasinghMS reviewed Jan 23, 2026

View reviewed changes

gurasinghMS added backport_1.7.2511 and removed backport_1.7.2511 labels Jan 31, 2026

mattkur force-pushed the cp-script branch from cc6c7e5 to 8a24192 Compare February 4, 2026 17:35

mattkur marked this pull request as draft February 6, 2026 22:57

mattkur force-pushed the cp-script branch from c2b404c to b171755 Compare February 12, 2026 18:48

mattkur added 3 commits February 12, 2026 18:48

repo_support: add a script that generates cherry pick PRs from main t…

79b0b93

…o a release branch, in correct merge order

pr feedback

dc52945

self feedback

43f7c05

mattkur force-pushed the cp-script branch from b171755 to 43f7c05 Compare February 12, 2026 18:48

mattkur marked this pull request as ready for review February 12, 2026 18:49

Merge branch 'main' into cp-script

2580170

alandau approved these changes Feb 12, 2026

View reviewed changes

		stderr = getattr(p, "stderr", "") or ""
		stdout = getattr(p, "stdout", "") or ""

-    else:
+    elif m := re.match(r"https://[\w:]+@github.com/", url):
+        path = url[m.end() :]
+    else:

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gurasinghMS commented Jan 23, 2026 •

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