split out cli validation from executionv1.13.5

A common pattern in our subcommands is to verify the arguments &
options before executing things.  For some subcommands, that check
stage is quite long which makes the execution function even bigger.
Lets split that logic out of the execute phase so it's easier to
manage these.

This is most noticeable in the sync subcommand whose Execute func
is quite large, and the option checking makes up ~15% of it.

The manifest command's Execute can be simplified significantly as
the optparse configuration always sets output_file to a string.

Change-Id: I7097847ff040e831345e63de6b467ee17609990e
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/234834
Reviewed-by: David Pursehouse <dpursehouse@collab.net>
Tested-by: Mike Frysinger <vapier@google.com>

1 files changed, 5 insertions, 6 deletions

diff --git a/subcmds/init.py b/subcmds/init.py
index eaa6da50..32663a04 100644
--- a/subcmds/init.py
+++ b/subcmds/init.py
@@ -436,18 +436,17 @@ to update the working directory files.
       print('   rm -r %s/.repo' % self.manifest.topdir)
       print('and try again.')
 
-  def Execute(self, opt, args):
-    git_require(MIN_GIT_VERSION, fail=True)
-
+  def ValidateOptions(self, opt, args):
     if opt.reference:
       opt.reference = os.path.expanduser(opt.reference)
 
     # Check this here, else manifest will be tagged "not new" and init won't be
     # possible anymore without removing the .repo/manifests directory.
     if opt.archive and opt.mirror:
-      print('fatal: --mirror and --archive cannot be used together.',
-            file=sys.stderr)
-      sys.exit(1)
+      self.OptionParser.error('--mirror and --archive cannot be used together.')
+
+  def Execute(self, opt, args):
+    git_require(MIN_GIT_VERSION, fail=True)
 
     self._SyncManifest(opt)
     self._LinkManifest(opt.manifest_name)