SL-20546: Use branch for autobuild package as well as release page.

which_branch.py has moved to viewer-build-util as a reusable action.

.github/workflows/build.yaml

@@ -24,7 +24,7 @@ jobs:
     outputs:
       viewer_channel: ${{ steps.build.outputs.viewer_channel }}
       viewer_version: ${{ steps.build.outputs.viewer_version }}
-      viewer_branch:  ${{ steps.build.outputs.viewer_branch }}
+      viewer_branch:  ${{ steps.which-branch.outputs.branch }}
       imagename: ${{ steps.build.outputs.imagename }}
     env:
       AUTOBUILD_ADDRSIZE: 64
@@ -187,15 +187,9 @@ jobs:
           if [[ "$GITHUB_REF_TYPE" == "tag" && "${GITHUB_REF_NAME:0:12}" == "Second_Life_" ]]
           then viewer_channel="${GITHUB_REF_NAME%#*}"
                export viewer_channel="${viewer_channel//_/ }"
-               # Since GITHUB_REF_NAME is a tag rather than a branch, we need
-               # to discover to what branch this tag corresponds.
-               viewer_branch="$(python3 .github/workflows/which_branch.py \
-                                --token "${{ github.token }}" ${{ github.workflow_sha }})"
           else export viewer_channel="Second Life Test"
-               viewer_branch="${GITHUB_REF_NAME}"
           fi
           echo "viewer_channel=$viewer_channel" >> "$GITHUB_OUTPUT"
-          echo "viewer_branch=$viewer_branch" >> "$GITHUB_OUTPUT"
 
           # On windows we need to point the build to the correct python
           # as neither CMake's FindPython nor our custom Python.cmake module

.github/workflows/which_branch.py

-#!/usr/bin/env python3
-"""\
-@file   which_branch.py
-@author Nat Goodspeed
-@date   2023-11-14
-@brief  Discover which git branch(es) correspond to a given commit hash.
-
-$LicenseInfo:firstyear=2023&license=viewerlgpl$
-Copyright (c) 2023, Linden Research, Inc.
-$/LicenseInfo$
-"""
-
-import github
-import re
-import sys
-import subprocess
-
-class Error(Exception):
-    pass
-
-def branches_for(token, commit, repo=None):
-    """
-    Use the GitHub REST API to discover which branch(es) correspond to the
-    passed commit hash. The commit string can actually be any of the ways git
-    permits to identify a commit:
-
-    https://git-scm.com/docs/gitrevisions#_specifying_revisions
-
-    branches_for() generates a (possibly empty) sequence of all the branches
-    of the specified repo for which the specified commit is the tip.
-
-    If repo is omitted or None, assume the current directory is a local clone
-    whose 'origin' remote is the GitHub repository of interest.
-    """
-    if not repo:
-        url = subprocess.check_output(['git', 'remote', 'get-url', 'origin'],
-                                      text=True)
-        parts = re.split(r'[:/]', url.rstrip())
-        repo = '/'.join(parts[-2:]).removesuffix('.git')
-
-    gh = github.MainClass.Github(token)
-    grepo = gh.get_repo(repo)
-    for branch in grepo.get_branches():
-        try:
-            delta = grepo.compare(base=commit, head=branch.name)
-        except github.GithubException:
-            continue
-
-        if delta.ahead_by == 0 and delta.behind_by == 0:
-            yield branch
-
-def main(*raw_args):
-    from argparse import ArgumentParser
-    parser = ArgumentParser(description=
-"%(prog)s reports the branch(es) for which the specified commit hash is the tip.",
-                            epilog="""\
-When GitHub Actions launches a tag build, it checks out the specific changeset
-identified by the tag, and so 'git branch' reports detached HEAD. But we use
-tag builds to build a GitHub 'release' of the tip of a particular branch, and
-it's useful to be able to identify which branch that is.
-""")
-    parser.add_argument('-t', '--token', required=True,
-                        help="""GitHub REST API access token""")
-    parser.add_argument('-r', '--repo',
-                        help="""GitHub repository name, in the form OWNER/REPOSITORY""")
-    parser.add_argument('commit',
-                        help="""commit hash at the tip of the sought branch""")
-
-    args = parser.parse_args(raw_args)
-    for branch in branches_for(token=args.token, commit=args.commit, repo=args.repo):
-        print(branch.name)
-
-if __name__ == "__main__":
-    try:
-        sys.exit(main(*sys.argv[1:]))
-    except Error as err:
-        sys.exit(str(err))