[bitbake-devel][PATCH] fetch2: git: Check if directory is a bare git repo

[Joshua Watt <jpewhacker@gmail.com>]

If the clone target directory exists, but isn't the valid top level of a
bare git repo, it needs to be erased and re-cloned. One example of how
this can happen is if a clone creates the directory, but then fails to
actual clone and make it a git repository. This left-over directory can
be particularly problematic if the download directory is a descent of
some top layer git repo (e.g. the default with poky), as the commands
that operate on the remote later will then mangle the layers git
repository instead of the download git repo.

Signed-off-by: Joshua Watt <JPEWhacker@gmail.com>
---
 bitbake/lib/bb/fetch2/git.py | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/bitbake/lib/bb/fetch2/git.py b/bitbake/lib/bb/fetch2/git.py
index 2a3c06fe4e9..112bed294f0 100644
--- a/bitbake/lib/bb/fetch2/git.py
+++ b/bitbake/lib/bb/fetch2/git.py
@@ -65,6 +65,7 @@ import fnmatch
 import os
 import re
 import shlex
+import shutil
 import subprocess
 import tempfile
 import bb
@@ -365,8 +366,29 @@ class Git(FetchMethod):
                 runfetchcmd(fetch_cmd, d, workdir=ud.clonedir)
         repourl = self._get_repo_url(ud)
 
+        needs_clone = False
+        if os.path.exists(ud.clonedir):
+            # The directory may exist, but not be the top level of a bare git
+            # repository in which case it needs to be deleted and re-cloned.
+            try:
+                # Since clones are bare, use --absolute-git-dir instead of --show-toplevel
+                output = runfetchcmd("LANG=C %s rev-parse --absolute-git-dir" % ud.basecmd, d, workdir=ud.clonedir)
+            except bb.fetch2.FetchError as e:
+                logger.warning("Unable to get top level for %s (not a git directory?): %s", ud.clonedir, e)
+                needs_clone = True
+            else:
+                toplevel = output.rstrip()
+                if os.path.abspath(toplevel) != os.path.abspath(ud.clonedir):
+                    logger.warning("Top level directory '%s' doesn't match expected '%s'. Re-cloning", toplevel, ud.clonedir)
+                    needs_clone = True
+
+            if needs_clone:
+                shutil.rmtree(ud.clonedir)
+        else:
+            needs_clone = True
+
         # If the repo still doesn't exist, fallback to cloning it
-        if not os.path.exists(ud.clonedir):
+        if needs_clone:
             # We do this since git will use a "-l" option automatically for local urls where possible,
             # but it doesn't work when git/objects is a symlink, only works when it is a directory.
             if repourl.startswith("file://"):
-- 
2.33.0