repo: upgrade to v2.11

Change-Id: Ia6388b624382c3b2db55c3cca5abacae7793e177
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2626049
Reviewed-by: Michael Mortensen <mmortensen@google.com>
Commit-Queue: Mike Frysinger <vapier@chromium.org>

repo_launcher

@@ -32,6 +32,13 @@ import subprocess
 import sys
 
 
+# These should never be newer than the main.py version since this needs to be a
+# bit more flexible with older systems.  See that file for more details on the
+# versions we select.
+MIN_PYTHON_VERSION_SOFT = (3, 6)
+MIN_PYTHON_VERSION_HARD = (3, 5)
+
+
 # Keep basic logic in sync with repo_trace.py.
 class Trace(object):
   """Trace helper logic."""
@@ -70,8 +77,6 @@ def check_python_version():
   def reexec(prog):
     exec_command([prog] + sys.argv)
 
-  MIN_PYTHON_VERSION = (3, 6)
-
   ver = sys.version_info
   major = ver.major
   minor = ver.minor
@@ -80,19 +85,26 @@ def check_python_version():
   if (major, minor) < (2, 7):
     print('repo: error: Your Python version is too old. '
           'Please use Python {}.{} or newer instead.'.format(
-              *MIN_PYTHON_VERSION), file=sys.stderr)
+              *MIN_PYTHON_VERSION_SOFT), file=sys.stderr)
     sys.exit(1)
 
   # Try to re-exec the version specific Python 3 if needed.
-  if (major, minor) < MIN_PYTHON_VERSION:
+  if (major, minor) < MIN_PYTHON_VERSION_SOFT:
     # Python makes releases ~once a year, so try our min version +10 to help
     # bridge the gap.  This is the fallback anyways so perf isn't critical.
-    min_major, min_minor = MIN_PYTHON_VERSION
+    min_major, min_minor = MIN_PYTHON_VERSION_SOFT
     for inc in range(0, 10):
       reexec('python{}.{}'.format(min_major, min_minor + inc))
 
-    # Try the generic Python 3 wrapper, but only if it's new enough.  We don't
-    # want to go from (still supported) Python 2.7 to (unsupported) Python 3.5.
+    # Fallback to older versions if possible.
+    for inc in range(MIN_PYTHON_VERSION_SOFT[1] - MIN_PYTHON_VERSION_HARD[1], 0, -1):
+      # Don't downgrade, and don't reexec ourselves (which would infinite loop).
+      if (min_major, min_minor - inc) <= (major, minor):
+        break
+      reexec('python{}.{}'.format(min_major, min_minor - inc))
+
+    # Try the generic Python 3 wrapper, but only if it's new enough.  If it
+    # isn't, we want to just give up below and make the user resolve things.
     try:
       proc = subprocess.Popen(
           ['python3', '-c', 'import sys; '
@@ -103,18 +115,20 @@ def check_python_version():
     except (OSError, subprocess.CalledProcessError):
       python3_ver = None
 
-    # The python3 version looks like it's new enough, so give it a try.
-    if python3_ver and python3_ver >= MIN_PYTHON_VERSION:
+    # If the python3 version looks like it's new enough, give it a try.
+    if (python3_ver and python3_ver >= MIN_PYTHON_VERSION_HARD
+        and python3_ver != (major, minor)):
       reexec('python3')
 
     # We're still here, so diagnose things for the user.
     if major < 3:
-      print('repo: warning: Python 2 is no longer supported; '
-            'Please upgrade to Python {}.{}+.'.format(*MIN_PYTHON_VERSION),
+      print('repo: error: Python 2 is no longer supported; '
+            'Please upgrade to Python {}.{}+.'.format(*MIN_PYTHON_VERSION_HARD),
             file=sys.stderr)
-    else:
+      sys.exit(1)
+    elif (major, minor) < MIN_PYTHON_VERSION_HARD:
       print('repo: error: Python 3 version is too old; '
-            'Please use Python {}.{} or newer.'.format(*MIN_PYTHON_VERSION),
+            'Please use Python {}.{} or newer.'.format(*MIN_PYTHON_VERSION_HARD),
             file=sys.stderr)
       sys.exit(1)
 
@@ -133,7 +147,7 @@ if not REPO_REV:
   REPO_REV = 'stable'
 
 # increment this whenever we make important changes to this script
-VERSION = (2, 8)
+VERSION = (2, 11)
 
 # increment this if the MAINTAINER_KEYS block is modified
 KEYRING_VERSION = (2, 3)
@@ -439,9 +453,11 @@ def get_gitc_manifest_dir():
 def gitc_parse_clientdir(gitc_fs_path):
   """Parse a path in the GITC FS and return its client name.
 
-  @param gitc_fs_path: A subdirectory path within the GITC_FS_ROOT_DIR.
+  Args:
+    gitc_fs_path: A subdirectory path within the GITC_FS_ROOT_DIR.
 
-  @returns: The GITC client name
+  Returns:
+    The GITC client name.
   """
   if gitc_fs_path == GITC_FS_ROOT_DIR:
     return None
@@ -966,9 +982,7 @@ def _FindRepo():
   repo = None
 
   olddir = None
-  while curdir != '/' \
-          and curdir != olddir \
-          and not repo:
+  while curdir != olddir and not repo:
     repo = os.path.join(curdir, repodir, REPO_MAIN)
     if not os.path.isfile(repo):
       repo = None