lorry: Install and use fudge_user_ids plugin for hg-fast-export

Mercurial allows arbitrary strings as user (committer) ids, while
Git requires a name and email address, and specific punctuation
around the address.

hg-fast-export has some provision for automatically fixing-up invalid
committer and author ids, but it doesn't catch everything.  Its
maintainer does not want to extend this, so we use a plugin instead.

* Add a plugin (fudge_user_ids) that should fix up all invalid ids.
* In setup.py:
  - Compile it at build time
  - Install it under a private data directory (/usr/share/lorry)
  - Clean up the bytecode
* In gitify_hg, check whether hg-fast-export supports plugins, and
  where our plugins are.  If this succeeds, add --plugin-path and
  --plugin options to enable fudge_user_ids.

Closes #11.

1 files changed, 23 insertions, 1 deletions

diff --git a/lorry b/lorry
index 81fdeb3..0e047db 100755
--- a/lorry
+++ b/lorry
@@ -766,8 +766,30 @@ class Lorry(cliapp.Application):
         self.prune_unreachable_marks(gitdir,
                                      os.path.join(gitdir, 'hg2git-marks'))
 
+        # Enable the fudge_user_ids plugin if possible
+        plugin_options = []
+        exit, out, _ = self.runcmd_unchecked(['hg-fast-export', '--help'])
+        if exit == 0 and b'--plugin' in out:
+            for plugin_path in [
+                    # Check under same directory as us, in case we are
+                    # not yet installed
+                    os.path.join(os.path.dirname(__file__),
+                                 'hg-fast-export/plugins'),
+                    # Try walking from <prefix>/bin/lorry to
+                    # <prefix>/share/lorry/...
+                    os.path.join(os.path.dirname(__file__),
+                                 '../share/lorry/hg-fast-export/plugins')
+                ]:
+                if os.path.exists(plugin_path):
+                    plugin_options += [
+                        '--plugin-path', plugin_path,
+                        '--plugin', 'fudge_user_ids'
+                    ]
+                    break
+
         self.progress('.. fast-exporting into git')
-        self.run_program(['hg-fast-export', '-r', '../hg', '--quiet', '--force'],
+        self.run_program(['hg-fast-export', '-r', '../hg', '--quiet', '--force',
+                          *plugin_options],
                          cwd=gitdir)
 
     def gitify_archive(self, archive_type, project_name, dirname, gitdir, spec):