X-Git-Url: https://git.madduck.net/etc/vim.git/blobdiff_plain/b517dfb396a82ef263f0d366c4dc107451cf0c3c..c4bd2e31ceeac84d68592986fe70920f3d3d0443:/docs/contributing/gauging_changes.md

diff --git a/docs/contributing/gauging_changes.md b/docs/contributing/gauging_changes.md
index 59c40eb..8562a83 100644
--- a/docs/contributing/gauging_changes.md
+++ b/docs/contributing/gauging_changes.md
@@ -7,18 +7,12 @@ It's recommended you evaluate the quantifiable changes your _Black_ formatting
 modification causes before submitting a PR. Think about if the change seems disruptive
 enough to cause frustration to projects that are already "black formatted".
 
-## black-primer
-
-`black-primer` is an obsolete tool (now replaced with `diff-shades`) that was used to
-gauge the impact of changes in _Black_ on open-source code. It is no longer used
-internally and will be removed from the _Black_ repository in the future.
-
 ## diff-shades
 
-diff-shades is a tool that runs _Black_ across a list of Git cloneable OSS projects
-recording the results. The main highlight feature of diff-shades is being able to
-compare two revisions of _Black_. This is incredibly useful as it allows us to see what
-exact changes will occur, say merging a certain PR.
+diff-shades is a tool that runs _Black_ across a list of open-source projects recording
+the results. The main highlight feature of diff-shades is being able to compare two
+revisions of _Black_. This is incredibly useful as it allows us to see what exact
+changes will occur, say merging a certain PR.
 
 For more information, please see the [diff-shades documentation][diff-shades].
 
@@ -26,35 +20,39 @@ For more information, please see the [diff-shades documentation][diff-shades].
 
 diff-shades is also the tool behind the "diff-shades results comparing ..." /
 "diff-shades reports zero changes ..." comments on PRs. The project has a GitHub Actions
-workflow which runs diff-shades twice against two revisions of _Black_ according to
-these rules:
+workflow that analyzes and compares two revisions of _Black_ according to these rules:
 
 |                       | Baseline revision       | Target revision              |
 | --------------------- | ----------------------- | ---------------------------- |
 | On PRs                | latest commit on `main` | PR commit with `main` merged |
 | On pushes (main only) | latest PyPI version     | the pushed commit            |
 
-Once finished, a PR comment will be posted embedding a summary of the changes and links
-to further information. If there's a pre-existing diff-shades comment, it'll be updated
-instead the next time the workflow is triggered on the same PR.
+For pushes to main, there's only one analysis job named `preview-changes` where the
+preview style is used for all projects.
+
+For PRs they get one more analysis job: `assert-no-changes`. It's similar to
+`preview-changes` but runs with the stable code style. It will fail if changes were
+made. This makes sure code won't be reformatted again and again within the same year in
+accordance to Black's stability policy.
 
-The workflow uploads 3-4 artifacts upon completion: the two generated analyses (they
-have the .json file extension), `diff.html`, and `.pr-comment.json` if triggered by a
-PR. The last one is downloaded by the `diff-shades-comment` workflow and shouldn't be
-downloaded locally. `diff.html` comes in handy for push-based or manually triggered
-runs. And the analyses exist just in case you want to do further analysis using the
-collected data locally.
+Additionally for PRs, a PR comment will be posted embedding a summary of the preview
+changes and links to further information. If there's a pre-existing diff-shades comment,
+it'll be updated instead the next time the workflow is triggered on the same PR.
 
-Note that the workflow will only fail intentionally if while analyzing a file failed to
+```{note}
+The `preview-changes` job will only fail intentionally if while analyzing a file failed to
 format. Otherwise a failure indicates a bug in the workflow.
+```
 
-```{tip}
-Maintainers with write access or higher can trigger the workflow manually from the
-Actions tab using the `workflow_dispatch` event. Simply select "diff-shades"
-from the workflows list on the left, press "Run workflow", and fill in which revisions
-and command line arguments to use.
+The workflow uploads several artifacts upon completion:
 
-Once finished, check the logs or download the artifacts for local use.
-```
+- The raw analyses (.json)
+- HTML diffs (.html)
+- `.pr-comment.json` (if triggered by a PR)
+
+The last one is downloaded by the `diff-shades-comment` workflow and shouldn't be
+downloaded locally. The HTML diffs come in handy for push-based where there's no PR to
+post a comment. And the analyses exist just in case you want to do further analysis
+using the collected data locally.
 
 [diff-shades]: https://github.com/ichard26/diff-shades#readme