3 files changed, 24 insertions, 5 deletions

diff --git a/git_command.py b/git_command.py
index 5017ea9b..4868ccdf 100644
--- a/git_command.py
+++ b/git_command.py
@@ -28,8 +28,17 @@ from repo_trace import REPO_TRACE, IsTrace, Trace
 from wrapper import Wrapper
 
 GIT = 'git'
-# Should keep in sync with the "repo" launcher file.
-MIN_GIT_VERSION = (2, 10, 2)
+# NB: These do not need to be kept in sync with the repo launcher script.
+# These may be much newer as it allows the repo launcher to roll between
+# different repo releases while source versions might require a newer git.
+#
+# The soft version is when we start warning users that the version is old and
+# we'll be dropping support for it.  We'll refuse to work with versions older
+# than the hard version.
+#
+# git-1.7 is in (EOL) Ubuntu Precise.  git-1.9 is in Ubuntu Trusty.
+MIN_GIT_VERSION_SOFT = (1, 9, 1)
+MIN_GIT_VERSION_HARD = (1, 7, 2)
 GIT_DIR = 'GIT_DIR'
 
 LAST_GITDIR = None
diff --git a/repo b/repo
index 2b125296..01d5c46d 100755
--- a/repo
+++ b/repo
@@ -166,7 +166,12 @@ TACbBS+Up3RpfYVfd63c1cDdlru13pQAn3NQy/SN858MkxN+zym86UBgOad2
 """
 
 GIT = 'git'                      # our git command
-MIN_GIT_VERSION = (2, 10, 2)     # minimum supported git version
+# NB: The version of git that the repo launcher requires may be much older than
+# the version of git that the main repo source tree requires.  Keeping this at
+# an older version also makes it easier for users to upgrade/rollback as needed.
+#
+# git-1.7 is in (EOL) Ubuntu Precise.
+MIN_GIT_VERSION = (1, 7, 2)      # minimum supported git version
 repodir = '.repo'                # name of repo's private directory
 S_repo = 'repo'                  # special repo repository
 S_manifests = 'manifests'        # special manifest repository
diff --git a/subcmds/init.py b/subcmds/init.py
index 6594a602..a7950069 100644
--- a/subcmds/init.py
+++ b/subcmds/init.py
@@ -34,7 +34,7 @@ from command import InteractiveCommand, MirrorSafeCommand
 from error import ManifestParseError
 from project import SyncBuffer
 from git_config import GitConfig
-from git_command import git_require, MIN_GIT_VERSION
+from git_command import git_require, MIN_GIT_VERSION_SOFT, MIN_GIT_VERSION_HARD
 import platform_utils
 
 class Init(InteractiveCommand, MirrorSafeCommand):
@@ -451,7 +451,12 @@ to update the working directory files.
       self.OptionParser.error('--mirror and --archive cannot be used together.')
 
   def Execute(self, opt, args):
-    git_require(MIN_GIT_VERSION, fail=True)
+    git_require(MIN_GIT_VERSION_HARD, fail=True)
+    if not git_require(MIN_GIT_VERSION_SOFT):
+      print('repo: warning: git-%s+ will soon be required; please upgrade your '
+            'version of git to maintain support.'
+            % ('.'.join(str(x) for x in MIN_GIT_VERSION_SOFT),),
+            file=sys.stderr)
 
     self._SyncManifest(opt)
     self._LinkManifest(opt.manifest_name)