[PATCH] fetch/git: Improve ls-remote handling for latest_revision

[Richard Purdie <richard.purdie@linuxfoundation.org>]

Currently the code ignores lightweight tags which has caused some user
complaints. We can't put the right search list in place easily since
the results don't come back in a good order, head happens to sort
before tags.

In the end I refactored the function so we get the complete list of
remotes and then we can filter it ourselves in the order we chose,
including checking for light weight tags, preferring the proper ones.

Hopefully this resolves the issues people have been seeing.

[YOCTO #6881]

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

diff --git a/bitbake/lib/bb/fetch2/git.py b/bitbake/lib/bb/fetch2/git.py
index f771fd0..44fc271 100644
--- a/bitbake/lib/bb/fetch2/git.py
+++ b/bitbake/lib/bb/fetch2/git.py
@@ -340,12 +340,19 @@ class Git(FetchMethod):
         """
         Compute the HEAD revision for the url
         """
+        output = self._lsremote(ud, d, "")
+        # Tags of the form ^{} may not work, need to fallback to other form
         if ud.unresolvedrev[name][:5] == "refs/":
-            search = "%s %s^{}" % (ud.unresolvedrev[name], ud.unresolvedrev[name])
+            head = ud.unresolvedrev[name]
+            tag = ud.unresolvedrev[name]
         else:
-            search = "refs/heads/%s refs/tags/%s^{}" % (ud.unresolvedrev[name], ud.unresolvedrev[name])
-        output = self._lsremote(ud, d, search)
-        return output.split()[0]
+            head = "refs/heads/%s" % ud.unresolvedrev[name]
+            tag = "refs/tags/%s" % ud.unresolvedrev[name]
+        for s in [head, tag + "^{}", tag]:
+            for l in output.split('\n'):
+                if s in l:
+                    return l.split()[0]
+        raise bb.fetch2.FetchError("Unable to resolve '%s' in upstream git repository in git ls-remote output" % ud.unresolvedrev[name])
 
     def latest_versionstring(self, ud, d):
         """