fetch/git: add support for keeping extra refs for shallow

By default, all unused refs (branches & tags) are removed from the repository,
as shallow processing scales with the number of refs it has to process. Add
the ability to explicitly specify additional refs to keep. This is
particularly useful for recipes with custom checkout processes, or whose
git-based versioning requires a tag be available (i.e. for `git describe
--tags`). The new `BB_GIT_SHALLOW_EXTRA_REFS` variable is a space-separated
list of refs, fully specified, and support wildcards.

Example usages:

    BB_GIT_SHALLOW_EXTRA_REFS = "refs/tags/v1.0"
    BB_GIT_SHALLOW_EXTRA_REFS += "refs/heads/*"

Signed-off-by: Christopher Larson <chris_larson@mentor.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 21 insertions, 1 deletions

diff --git a/lib/bb/fetch2/git.py b/lib/bb/fetch2/git.py
index 250109bf9..aa972c5cf 100644
--- a/lib/bb/fetch2/git.py
+++ b/lib/bb/fetch2/git.py
@@ -72,6 +72,7 @@ Supported SRC_URI options are:
 
 import collections
 import errno
+import fnmatch
 import os
 import re
 import subprocess
@@ -180,6 +181,7 @@ class Git(FetchMethod):
             ud.cloneflags += " --mirror"
 
         ud.shallow = d.getVar("BB_GIT_SHALLOW") == "1"
+        ud.shallow_extra_refs = (d.getVar("BB_GIT_SHALLOW_EXTRA_REFS") or "").split()
 
         depth_default = d.getVar("BB_GIT_SHALLOW_DEPTH")
         if depth_default is not None:
@@ -265,8 +267,13 @@ class Git(FetchMethod):
                 if depth:
                     tarballname = "%s-%s" % (tarballname, depth)
 
+            shallow_refs = []
             if not ud.nobranch:
-                tarballname = "%s_%s" % (tarballname, "_".join(sorted(ud.branches.values())).replace('/', '.'))
+                shallow_refs.extend(ud.branches.values())
+            if ud.shallow_extra_refs:
+                shallow_refs.extend(r.replace('refs/heads/', '').replace('*', 'ALL') for r in ud.shallow_extra_refs)
+            if shallow_refs:
+                tarballname = "%s_%s" % (tarballname, "_".join(sorted(shallow_refs)).replace('/', '.'))
 
             fetcher = self.__class__.__name__.lower()
             ud.shallowtarball = '%sshallow_%s.tar.gz' % (fetcher, tarballname)
@@ -408,6 +415,19 @@ class Git(FetchMethod):
         # Map srcrev+depths to revisions
         shallow_revisions = runfetchcmd("%s rev-parse %s" % (ud.basecmd, " ".join(to_parse)), d, workdir=dest).splitlines()
 
+        # Apply extra ref wildcards
+        all_refs = runfetchcmd('%s for-each-ref "--format=%%(refname)"' % ud.basecmd,
+                               d, workdir=dest).splitlines()
+        for r in ud.shallow_extra_refs:
+            if not ud.bareclone:
+                r = r.replace('refs/heads/', 'refs/remotes/origin/')
+
+            if '*' in r:
+                matches = filter(lambda a: fnmatch.fnmatchcase(a, r), all_refs)
+                shallow_branches.extend(matches)
+            else:
+                shallow_branches.append(r)
+
         # Make the repository shallow
         shallow_cmd = ['git', 'make-shallow', '-s']
         for b in shallow_branches: