version: add source versions & User-Agents to the output

Depending on where/how repo is invoked, the active version might be
from a git tree, and it might be different from the .repo/repo.git/
version in the current repo client checkout.  Report both if they're
different so it's clearer.

Lets also include the two different User-Agent's that we set up when
talking to networked services.

Bug: https://crbug.com/gerrit/11144
Change-Id: I2ebb6e3ac30e374a8406cab3e4438087246a8c57
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/239234
Reviewed-by: David Pursehouse <dpursehouse@collab.net>
Tested-by: Mike Frysinger <vapier@google.com>

subcmds/version.py

@@ -17,7 +17,7 @@
 from __future__ import print_function
 import sys
 from command import Command, MirrorSafeCommand
-from git_command import git
+from git_command import git, RepoSourceVersion, user_agent
 from git_refs import HEAD
 
 class Version(Command, MirrorSafeCommand):
@@ -34,12 +34,20 @@ class Version(Command, MirrorSafeCommand):
     rp = self.manifest.repoProject
     rem = rp.GetRemote(rp.remote.name)
 
-    print('repo version %s' % rp.work_git.describe(HEAD))
+    # These might not be the same.  Report them both.
+    src_ver = RepoSourceVersion()
+    rp_ver = rp.bare_git.describe(HEAD)
+    print('repo version %s' % rp_ver)
     print('       (from %s)' % rem.url)
 
     if Version.wrapper_path is not None:
       print('repo launcher version %s' % Version.wrapper_version)
       print('       (from %s)' % Version.wrapper_path)
 
+      if src_ver != rp_ver:
+        print('       (currently at %s)' % src_ver)
+
+    print('repo User-Agent %s' % user_agent.repo)
     print('git %s' % git.version_tuple().full)
+    print('git User-Agent %s' % user_agent.git)
     print('Python %s' % sys.version)