Bug 301388 – [ews-build] DetermineLandedIdentifier should support Canonical-link trailer

• Component: Tools / Tests
• Status: RESOLVED FIXED

[Sam Sneddon [:gsnedders]]

As part of bug 266028, we need to migrate everything to supporting actual git trailers.

On EWS, we have:

```
Tools/CISupport/ews-build/steps.py
6314:    command = ['/bin/bash', '--posix', '-o', 'pipefail', '-c', "git log -1 --no-decorate | grep 'Canonical link: https://commits\\.webkit\\.org/'"]
6315:    CANONICAL_LINK_RE = re.compile(r'\ACanonical link: https://commits\.webkit\.org/(?P<identifier>\d+.?\d*@\S+)\Z')
6341:            match = self.CANONICAL_LINK_RE.match(line[4:])
```

(Plus associated, currently disabled, unit tests.)

We probably want to run something more like the following, and change the regex to include a hyphen:

```
git log --format=%B -1 | \
  sed -e 's/Canonical link:/Canonical-link:/' | \
  git -c trailer.Canonical-link.key=Canonical-link -c trailer.Identifier.key=Identifier -c trailer.git-svn-id.key=git-svn-id interpret-trailers --parse --no-divider
```

We need to specify the trailer.xxx.key config options because:

> Existing trailers are extracted from the input message by looking for a group of one or more lines that (i) is all trailers, or (ii) contains at least one Git-generated or user-configured trailer and consists of at least 25% trailers.

And we have plenty of groups which aren't all trailers in WebKit.

[Radar WebKit Bug Importer]

<rdar://problem/163304249>

[Sam Sneddon [:gsnedders]]

Pull request: https://github.com/WebKit/WebKit/pull/64715

[EWS]

Committed 314674@main (4e8d725445b3): <https://commits.webkit.org/314674@main>

Reviewed commits have been landed. Closing PR #64715 and removing active labels.