repo: refactor help output handling

Currently we have the behavior:
* `repo`: Equivalent to `repo help` -- only shows common subcommands
  (with short description), and then exits 0.
* `repo --help`: Shows repo's core options, lists all commands (no
  specific info), and then exits 0.

The first case is not behaving well:
* If you run `repo` without a specific subcommand, that's an error,
  so we should be exiting 1 instead.
* Showing only subcommands and no actual option summary makes it seem
  like repo itself doesn't take any options.  This confuses users.

Let's rework things a bit.  Now we have the behavior:
* `repo`: Shows repo's core options, lists all commands (no specific
  info), and then exits 1.
* `repo --help`: Shows repo's core options, shows common subcommands
  (with short description), and then exits 0.
* `repo --help-all`: Shows repo's core options, shows all subcommands
  (with short description), and then exits 0.

Basically we swap the behavior of `repo` and `repo --help`, and fix
the exit status when the subcommand is missing.

The addition of --help-all is mostly for the man pages.  We were
relying on `repo help --all` to generate the repo(1) man page, but
that too omitted the core repo options.  Now the man page includes
all the core repo options and provides a summary of all commands.

Change-Id: I1f99b99d5b8af2591f96a078d0647a3d76d6b0fc
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/312908
Reviewed-by: Xin Li <delphij@google.com>
Tested-by: Mike Frysinger <vapier@google.com>

1 files changed, 23 insertions, 7 deletions

diff --git a/main.py b/main.py
index 253f3112..229cb729 100755
--- a/main.py
+++ b/main.py
@@ -95,6 +95,8 @@ global_options = optparse.OptionParser(
     add_help_option=False)
 global_options.add_option('-h', '--help', action='store_true',
                           help='show this help message and exit')
+global_options.add_option('--help-all', action='store_true',
+                          help='show this help message with all subcommands and exit')
 global_options.add_option('-p', '--paginate',
                           dest='pager', action='store_true',
                           help='display command output in the pager')
@@ -128,6 +130,23 @@ class _Repo(object):
     self.repodir = repodir
     self.commands = all_commands
 
+  def _PrintHelp(self, short: bool = False, all_commands: bool = False):
+    """Show --help screen."""
+    global_options.print_help()
+    print()
+    if short:
+      commands = ' '.join(sorted(self.commands))
+      wrapped_commands = textwrap.wrap(commands, width=77)
+      print('Available commands:\n  %s' % ('\n  '.join(wrapped_commands),))
+      print('\nRun `repo help <command>` for command-specific details.')
+      print('Bug reports:', Wrapper().BUG_URL)
+    else:
+      cmd = self.commands['help']()
+      if all_commands:
+        cmd.PrintAllCommandsBody()
+      else:
+        cmd.PrintCommonCommandsBody()
+
   def _ParseArgs(self, argv):
     """Parse the main `repo` command line options."""
     for i, arg in enumerate(argv):
@@ -177,19 +196,16 @@ class _Repo(object):
       SetTrace()
 
     # Handle options that terminate quickly first.
-    if gopts.help:
-      global_options.print_help()
-      commands = ' '.join(sorted(self.commands))
-      wrapped_commands = textwrap.wrap(commands, width=77)
-      print('\nAvailable commands:\n  %s' % ('\n  '.join(wrapped_commands),))
-      print('\nRun `repo help <command>` for command-specific details.')
+    if gopts.help or gopts.help_all:
+      self._PrintHelp(short=False, all_commands=gopts.help_all)
       return 0
     elif gopts.show_version:
       # Always allow global --version regardless of subcommand validity.
       name = 'version'
     elif not name:
       # No subcommand specified, so show the help/subcommand.
-      name = 'help'
+      self._PrintHelp(short=True)
+      return 1
 
     SetDefaultColoring(gopts.color)