launcher: support Python 3.5 for now
The codebase still supports Python 3.5, so allow use of that instead
of requiring Python 3.6+. Supporting this mode well is a bit tricky
as we want to first scan for newer versions before falling back to
older ones. And we have to avoid infinite loops in the process.
Bug: https://crbug.com/gerrit/13795
Change-Id: I47949a173899bfa9ab20d3fefa1a97bf002659f6
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/292442
Reviewed-by: Michael Mortensen <mmortensen@google.com>
Tested-by: Mike Frysinger <vapier@google.com>
diff --git a/repo b/repo
index f1b15c5..dae37bd 100755
--- a/repo
+++ b/repo
@@ -32,6 +32,13 @@
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 reexec(prog):
exec_command([prog] + sys.argv)
- MIN_PYTHON_VERSION = (3, 6)
-
ver = sys.version_info
major = ver.major
minor = ver.minor
@@ -80,17 +85,24 @@
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))
+ # 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. We don't
# want to go from (still supported) Python 2.7 to (unsupported) Python 3.5.
try:
@@ -103,18 +115,19 @@
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),
+ 'Please upgrade to Python {}.{}+.'.format(*MIN_PYTHON_VERSION_HARD),
file=sys.stderr)
- else:
+ 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)
