branches: Describe output format in repo help branches

Signed-off-by: Shawn O. Pearce <sop@google.com>

git_command.py

@@ -68,6 +68,30 @@ class _GitCall(object):
     return fun
 git = _GitCall()
 
+_git_version = None
+
+def git_require(min_version, fail=False):
+  global _git_version
+
+  if _git_version is None:
+    ver_str = git.version()
+    if ver_str.startswith('git version '):
+      _git_version = tuple(
+        map(lambda x: int(x),
+          ver_str[len('git version '):].strip().split('.')[0:3]
+        ))
+    else:
+      print >>sys.stderr, 'fatal: "%s" unsupported' % ver_str
+      sys.exit(1)
+
+  if min_version <= _git_version:
+    return True
+  if fail:
+    need = '.'.join(map(lambda x: str(x), min_version))
+    print >>sys.stderr, 'fatal: git %s or later required' % need
+    sys.exit(1)
+  return False
+
 class GitCommand(object):
   def __init__(self,
                project,

subcmds/branches.py

@@ -61,6 +61,33 @@ class Branches(Command):
 %prog [<project>...]
 
 Summarizes the currently available topic branches.
+
+Branch Display
+--------------
+
+The branch display output by this command is organized into four
+columns of information; for example:
+
+ *P nocolor                   | in repo
+    repo2                     |
+
+The first column contains a * if the branch is the currently
+checked out branch in any of the specified projects, or a blank
+if no project has the branch checked out.
+
+The second column contains either blank, p or P, depending upon
+the upload status of the branch.
+
+ (blank): branch not yet published by repo upload
+       P: all commits were published by repo upload
+       p: only some commits were published by repo upload
+
+The third column contains the branch name.
+
+The fourth column (after the | separator) lists the projects that
+the branch appears in, or does not appear in.  If no project list
+is shown, then the branch appears in all projects.
+
 """
 
   def Execute(self, opt, args):

subcmds/grep.py

@@ -17,7 +17,7 @@ import sys
 from optparse import SUPPRESS_HELP
 from color import Coloring
 from command import PagedCommand
-from git_command import GitCommand
+from git_command import git_require, GitCommand
 
 class GrepColoring(Coloring):
   def __init__(self, config):
@@ -158,7 +158,7 @@ contain a line that matches both expressions:
     out = GrepColoring(self.manifest.manifestProject.config)
 
     cmd_argv = ['grep']
-    if out.is_on:
+    if out.is_on and git_require((1,6,3)):
       cmd_argv.append('--color')
     cmd_argv.extend(getattr(opt,'cmd_argv',[]))
 

subcmds/init.py

@@ -20,7 +20,7 @@ from color import Coloring
 from command import InteractiveCommand, MirrorSafeCommand
 from error import ManifestParseError
 from project import SyncBuffer
-from git_command import git, MIN_GIT_VERSION
+from git_command import git_require, MIN_GIT_VERSION
 
 class Init(InteractiveCommand, MirrorSafeCommand):
   common = True
@@ -85,19 +85,6 @@ to update the working directory files.
                  dest='no_repo_verify', action='store_true',
                  help='do not verify repo source code')
 
-  def _CheckGitVersion(self):
-    ver_str = git.version()
-    if not ver_str.startswith('git version '):
-      print >>sys.stderr, 'error: "%s" unsupported' % ver_str
-      sys.exit(1)
-
-    ver_str = ver_str[len('git version '):].strip()
-    ver_act = tuple(map(lambda x: int(x), ver_str.split('.')[0:3]))
-    if ver_act < MIN_GIT_VERSION:
-      need = '.'.join(map(lambda x: str(x), MIN_GIT_VERSION))
-      print >>sys.stderr, 'fatal: git %s or later required' % need
-      sys.exit(1)
-
   def _SyncManifest(self, opt):
     m = self.manifest.manifestProject
     is_new = not m.Exists
@@ -214,7 +201,7 @@ to update the working directory files.
       gc.SetString('color.ui', 'auto')
 
   def Execute(self, opt, args):
-    self._CheckGitVersion()
+    git_require(MIN_GIT_VERSION, fail=True)
     self._SyncManifest(opt)
     self._LinkManifest(opt.manifest_name)