Ci/pr size check by AlexAxthelm · Pull Request #338 · RMI/stitch

AlexAxthelm · 2026-10-20T14:49:40Z

Adds a CI check to the "Admin" family to check that PRs are smallish (currently 600 LoC changed/added/removed). The bulk of this is in a bash script inlined in the workflow file (should be extracted if we move this over to RMI/actions), which has some modest hardening (such as checking that line limit is an integer, or failing if the exemptions are malformed).

Some neat features:

Can exempt certain files (lockfiles can really blow up the line limits)
Don't run for certain HEAD branches: next, production, so that releases and backmerges, which are gong to be bigger than a single PR's worth

What

Adds a Check PR size job to Admin Checks. It fails a PR that changes more than 600 lines (additions + deletions), so oversized PRs get split before they reach review.

How it works

New reusable workflow admin-pr-size.yml, called from admin.yml, with three inputs:
- max_lines: default 600. Must be a whole number; anything else fails the check with a clear error.
- ignore: newline-delimited git glob pathspecs that aren't counted. Stitch passes **/uv.lock and **/package-lock.json.
- exempt_head_branches: JSON array of source branches in this repo whose PRs skip the check. Stitch passes main, next, production (release promotions and backmerges).
Counts lines with git diff --numstat from the merge base with the target branch's current tip to the PR head. This matches GitHub's "Files changed" view. git diff --stat is printed to the job log so authors can see where the lines are.
Only runs on pull_request events. It's skipped on push/schedule/dispatch runs of Admin Checks. Fork PRs are never exempt, even from a branch named main.
Documented in CONTRIBUTING.md under "PR Size".

Impact on recent PRs

Of the last ~48 non-release PRs, 7 would have failed: #316, #293, #283, #282, #277, #276, #267. Dependabot PRs pass because lockfiles are ignored (#270: 607 raw lines → 16 counted).

Not in this PR

Not a required status check yet. Follow-up: add Check PR size / Check PR size to gitflow-main.overlay.json and update the live ruleset at the same time.
Retargeting a PR's base doesn't re-run the check until the next push, because Admin Checks uses the default pull_request event types.

Testing

Replayed the step's script locally against merged PRs' base/head commits. Counts match GitHub's:
- STIT-743 feat(frontend): persist list state in the URL #276 → 1014 (fails)
- STIT-795: Add a sort control to the Merge Review queue #316 → 650 (fails)
- feat(frontend): use dropdowns for fixed-value fields in manual edit (STIT-791) #303 → 188 (passes)
- build(deps-dev): bump the npm-dependencies group in /deployments/stitch-frontend with 8 updates #270 → 16 (passes; 607 without the ignore list)
Replayed feat(llm): AI enrichment for all descriptive fields + bulk enrich #282, which merged main partway through: 650 against the target's tip (matches GitHub), versus 7040 if diffed from the pre-merge base.
max_lines validation: 600.5, -1, empty, abc and " 600" fail with an error. Before the fix, 600.5 silently passed a 1014-line PR.
Edge cases: an empty diff passes, blank or indented ignore lines are handled, and a bad ref fails the step with git's error.
yamllint: only the existing on: truthy warnings.
Not yet exercised: the job-level if: (exemption + same-repo condition). This PR's own run covers the non-exempt path. The exempt path will run on the next release PR.

AI assistance

Claude Code drafted the workflow and docs, ran the local replays above, and reviewed the branch. I made the design decisions (fail with no override, configurable ignore list, release/backmerge exemption, not required yet), simplified the script and messages, and reviewed each change before committing.

🤖 Generated with Claude Code

Add a reusable admin-pr-size workflow that fails a pull request when it changes more than `max_lines` lines (additions + deletions, default 600), counted with `git diff --numstat` against the merge base. An `ignore` input takes git glob pathspecs whose changes are not counted; stitch ignores uv.lock and package-lock.json. Release promotions and backmerges (PRs whose source branch is main, next, or production) are exempt, and the check only runs on pull_request events. It is not yet a required status check. Document the limit in CONTRIBUTING.md. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

A PR from a fork's `main` (the usual way external contributors submit, per CONTRIBUTING.md) matched the release/backmerge exemption because it only compared the source branch name. Also require the head repository to be this repository. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Use origin/$BASE_REF instead of the event's base SHA as the left side of the three-dot diff. If the base SHA predates a merge of the target into the PR branch, the merge base falls back to it and the target's own changes get counted (replaying #282 this way gives 7040 lines instead of 650). Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Move the release/backmerge branch list out of the reusable workflow and into admin.yml, next to the ignore list, so all of stitch's PR size policy lives in the caller. The input is a JSON array because the job-level `if:` can only read lists via fromJSON(); it defaults to no exemptions. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

`max_lines` is a number input, so decimals are accepted, but the `-gt` comparison is integer-only. Inside an `if`, its error status was treated as false and the check passed (e.g. 1014 lines vs max_lines=600.5). Validate it up front and fail with a clear message instead. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

github-actions · 2026-10-20T14:54:32Z

CD summary `b7948f3`

Frontend: https://witty-mushroom-017a3dc1e-338.westus2.1.azurestaticapps.net

Deployments (3)

service	url	fqdn
api	open	`pr-0338-api.purplegrass-c07d0a94.westus2.azurecontainerapps.io`
frontend	https://witty-mushroom-017a3dc1e-338.westus2.1.azurestaticapps.net
stitch-llm	open	`pr-0338-llm.purplegrass-c07d0a94.westus2.azurecontainerapps.io`

Database (1)

db_name	postgres_host	postgres_port	postgres_db
pr_0338	`stitch-dev.postgres.database.azure.com`	`5432`	`pr_0338`

Jobs (2)

job	image	postgres_db	api_url	auth_mode
db-migrations	`ghcr.io/rmi/stitch-api:pr-0338@sha256:fc4bc9ad3b229857d3e4ec92580cec7b362761d9932d20f402b07e1f74010390`	`pr_0338`
seed	`ghcr.io/rmi/stitch-seed:pr-0338@sha256:4eb21dabaf03de8d1db2eeb375dfa911371fdbb5835cc6361e095ccb93b35618`		`https://pr-0338-api.purplegrass-c07d0a94.westus2.azurecontainerapps.io/api/v1`	`stitch-client-bearer-token`

Images (3)

build_time	commit_time	git_sha	image	image_digest
2026-10-20T14:50:00Z	2026-10-20T14:49:40Z	`5ce8055`	`ghcr.io/rmi/stitch-api:pr-0338`	`ghcr.io/rmi/stitch-api:pr-0338@sha256:fc4bc9ad3b229857d3e4ec92580cec7b362761d9932d20f402b07e1f74010390`
2026-10-20T14:49:58Z	2026-10-20T14:49:40Z	`5ce8055`	`ghcr.io/rmi/stitch-seed:pr-0338`	`ghcr.io/rmi/stitch-seed:pr-0338@sha256:4eb21dabaf03de8d1db2eeb375dfa911371fdbb5835cc6361e095ccb93b35618`
2026-10-20T14:50:01Z	2026-10-20T14:49:40Z	`5ce8055`	`ghcr.io/rmi/stitch-stitch-llm:pr-0338`	`ghcr.io/rmi/stitch-stitch-llm:pr-0338@sha256:5601053519298cc6ea47ad2b0268a04a7801e9428361cd00ec9c35564878a3c6`

github-actions · 2026-10-20T15:00:50Z

CD summary `4c7728d`

Frontend: https://witty-mushroom-017a3dc1e-338.westus2.1.azurestaticapps.net

Deployments (3)

service	url	fqdn
api	open	`pr-0338-api.purplegrass-c07d0a94.westus2.azurecontainerapps.io`
frontend	https://witty-mushroom-017a3dc1e-338.westus2.1.azurestaticapps.net
stitch-llm	open	`pr-0338-llm.purplegrass-c07d0a94.westus2.azurecontainerapps.io`

Database (1)

db_name	postgres_host	postgres_port	postgres_db
pr_0338	`stitch-dev.postgres.database.azure.com`	`5432`	`pr_0338`

Jobs (1)

job	image	postgres_db
db-migrations	`ghcr.io/rmi/stitch-api:pr-0338@sha256:89b3f6bc5fa5c1dcec2b57bb2f62880554e1f8bb23c5f25f123e7568e99fec97`	`pr_0338`

Images (3)

build_time	commit_time	git_sha	image	image_digest
2026-10-20T14:56:30Z	2026-10-20T14:56:04Z	`f3a67e9`	`ghcr.io/rmi/stitch-api:pr-0338`	`ghcr.io/rmi/stitch-api:pr-0338@sha256:89b3f6bc5fa5c1dcec2b57bb2f62880554e1f8bb23c5f25f123e7568e99fec97`
2026-10-20T14:56:53Z	2026-10-20T14:56:04Z	`f3a67e9`	`ghcr.io/rmi/stitch-seed:pr-0338`	`ghcr.io/rmi/stitch-seed:pr-0338@sha256:895add6c38e9298b5575d58c1146eb3d6a9e8e7b5c88c3e8a556e99300458516`
2026-10-20T14:56:28Z	2026-10-20T14:56:04Z	`f3a67e9`	`ghcr.io/rmi/stitch-stitch-llm:pr-0338`	`ghcr.io/rmi/stitch-stitch-llm:pr-0338@sha256:f3b60b7d5337dc6ec19436a353cc741eec2e7cb252b6e25556bad54fe138dc35`

Copilot

🟡 Changes recommended

Two moderate findings remain regarding exemption input validation and the check being modifiable by the PR itself.

1 open issue

Validate exemption input is an array before applying branch checks · New

What changed in this PR

Adds a reusable Admin CI check limiting pull requests to 600 changed lines, with lockfile exclusions and branch exemptions.

Changes:

Documents PR size policy.
Integrates the check into Admin Checks.
Adds diff-based counting, validation, and exemptions.

File	Description
`CONTRIBUTING.md`	Documents PR size limits and exemptions.
`.github/workflows/admin.yml`	Configures the PR-size check.
`.github/workflows/admin-pr-size.yml`	Implements validation, exemptions, and line counting.

_{Review effort: Lite}

github-actions · 2026-10-20T15:12:31Z

CD summary `b1a90e2`

Frontend: https://witty-mushroom-017a3dc1e-338.westus2.1.azurestaticapps.net

Deployments (3)

service	url	fqdn
api	open	`pr-0338-api.purplegrass-c07d0a94.westus2.azurecontainerapps.io`
frontend	https://witty-mushroom-017a3dc1e-338.westus2.1.azurestaticapps.net
stitch-llm	open	`pr-0338-llm.purplegrass-c07d0a94.westus2.azurecontainerapps.io`

Database (1)

db_name	postgres_host	postgres_port	postgres_db
pr_0338	`stitch-dev.postgres.database.azure.com`	`5432`	`pr_0338`

Jobs (1)

job	image	postgres_db
db-migrations	`ghcr.io/rmi/stitch-api:pr-0338@sha256:51289a67187091beab3a541fadbd9efb2f98b8e71318e1042ad06dd77cf1e934`	`pr_0338`

Images (3)

build_time	commit_time	git_sha	image	image_digest
2026-10-20T15:08:07Z	2026-10-20T15:07:42Z	`b86411a`	`ghcr.io/rmi/stitch-api:pr-0338`	`ghcr.io/rmi/stitch-api:pr-0338@sha256:51289a67187091beab3a541fadbd9efb2f98b8e71318e1042ad06dd77cf1e934`
2026-10-20T15:08:01Z	2026-10-20T15:07:42Z	`b86411a`	`ghcr.io/rmi/stitch-seed:pr-0338`	`ghcr.io/rmi/stitch-seed:pr-0338@sha256:3c29aa13d94b7ed4f779d37686dc414ce82579ba5a53cdf8668aab1176174426`
2026-10-20T15:08:01Z	2026-10-20T15:07:42Z	`b86411a`	`ghcr.io/rmi/stitch-stitch-llm:pr-0338`	`ghcr.io/rmi/stitch-stitch-llm:pr-0338@sha256:72501767a1efe88963cee19b08a2d51feb97d91c3262a3fd5bb96906c297f673`

The job-level `if:` used contains(fromJSON(...)), which matches substrings if the input isn't an array and ignores case, so a same-repo branch named `Main` or `NEXT` was exempt. Check the exemption in the bash step with an exact, case-sensitive match instead, and make exempt_head_branches newline-delimited like `ignore`. Exempt PRs now pass with a notice instead of being skipped. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

github-actions · 2026-10-20T15:38:35Z

CD summary `7149c98`

Database (1)

db_name	postgres_host	postgres_port	postgres_db
pr_0338	`stitch-dev.postgres.database.azure.com`	`5432`	`pr_0338`

Jobs (1)

job	image	postgres_db
db-migrations	`ghcr.io/rmi/stitch-api:pr-0338@sha256:c74266db14c72c08155b248a35a3e4d4d723f07bacef0e5c0f992ca76f47b18d`	`pr_0338`

Images (3)

build_time	commit_time	git_sha	image	image_digest
2026-10-20T15:34:09Z	2026-10-20T15:33:49Z	`52748de`	`ghcr.io/rmi/stitch-api:pr-0338`	`ghcr.io/rmi/stitch-api:pr-0338@sha256:c74266db14c72c08155b248a35a3e4d4d723f07bacef0e5c0f992ca76f47b18d`
2026-10-20T15:34:08Z	2026-10-20T15:33:49Z	`52748de`	`ghcr.io/rmi/stitch-seed:pr-0338`	`ghcr.io/rmi/stitch-seed:pr-0338@sha256:6e957368ca5b5a45800fa19924ce735c0dd910ef969ba3e3f1f8e9b0cf739cc3`
2026-10-20T15:34:11Z	2026-10-20T15:33:49Z	`52748de`	`ghcr.io/rmi/stitch-stitch-llm:pr-0338`	`ghcr.io/rmi/stitch-stitch-llm:pr-0338@sha256:e4a7c61c70954a1ba3a7341731041fff8c2275218cb5a1648b1787de6dceb79a`

mbarlow12

Looks good. 💯

mbarlow12 · 2026-10-20T19:38:36Z

I also just realized that I'd absolutely use this locally during development. I think Claude could also make some great use of it as a halting condition and/or warning. It's a strong signal that the workstream might be going in an undesirable direction, especially if it's run early in implementation and there's a lot left to change.

It could as a bit of a self-check that's run periodically by the agent, and if it fails, the agent knows to stop and discuss the plan/design with the user. Or could be use in a loop to keep tests passing while reducing change size.

AlexAxthelm · 2026-10-21T06:46:57Z

I also just realized that I'd absolutely use this locally during development. I think Claude could also make some great use of it as a halting condition and/or warning. It's a strong signal that the workstream might be going in an undesirable direction, especially if it's run early in implementation and there's a lot left to change.

It could as a bit of a self-check that's run periodically by the agent, and if it fails, the agent knows to stop and discuss the plan/design with the user. Or could be use in a loop to keep tests passing while reducing change size.

Hmm. one of the things that I was back-and-forthing with myself with on this was to pull the inline bash script out to a separate file. But that sounds useful so that we could invoke it separately in local dev cycles

AlexAxthelm and others added 6 commits October 20, 2026 15:42

simplify bash script

7c6daf9

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Merge branch 'main' into ci/pr-size-check

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Ci/pr size check - #338

Ci/pr size check#338
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CD summary `b7948f3`

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CD summary `b1a90e2`

CD summary `7149c98`

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