[library-web] get default branch name from repository for modules downloaded using git

[Frederic Peters <fpeters src gnome org>]

commit 476e16c8eff58745fee667bfbb159db4a3f9e3dc
Author: Frédéric Péters <fpeters 0d be>
Date:   Tue Jun 16 23:17:20 2020 +0200

    get default branch name from repository for modules downloaded using git

 src/lgo.py | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)
---
diff --git a/src/lgo.py b/src/lgo.py
index f6684ca..ac41251 100755
--- a/src/lgo.py
+++ b/src/lgo.py
@@ -309,7 +309,7 @@ class Lgo(App):
             branch_name = cgi.parse_qs(parsed_url.query).get('branch')[0]
             version_value = cgi.parse_qs(parsed_url.query).get('version')[0]
 
-            if branch_name == 'master':
+            if branch_name in ('main', 'master'):
                 if not version_value.startswith('.'.join(branch_name.split('-')[1:])):
                     logging.debug('ignoring git for %s (version != branch)' % module_name)
                     return
@@ -346,7 +346,13 @@ class Lgo(App):
             subp.wait()
             if subp.returncode != 0:
                 if self.latest_stable_release and fake_version_number.startswith(self.latest_stable_release):
-                    subprocess.Popen(['git', 'checkout', 'master'],
+                    try:
+                        default_branch = subprocess.check_output(
+                                ['git', 'symbolic-ref', '--short', 'refs/remotes/origin/HEAD'],
+                                cwd=module_git_clone_dir).decode('ascii').strip()
+                    except CommandError:
+                        default_branch = 'master'
+                    subprocess.Popen(['git', 'checkout', default_branch],
                             cwd=module_git_clone_dir).wait()
                 else:
                     logging.debug('branch do not exist, skipping')