From e908b80618f918357c0e87427e7277fe251889f5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=D0=BD=D0=B0=D0=B1?= <nabijaczleweli@nabijaczleweli.xyz>
Date: Wed, 5 Aug 2020 22:48:57 +0200
Subject: [PATCH] Add migration to fix up some broken HEADs found by 0.55.x
 code

---
 .../9f72f0dea908_clean_up_broken_heads.py     | 84 +++++++++++++++++++
 1 file changed, 84 insertions(+)
 create mode 100644 gitsrht/alembic/versions/9f72f0dea908_clean_up_broken_heads.py

diff --git a/gitsrht/alembic/versions/9f72f0dea908_clean_up_broken_heads.py b/gitsrht/alembic/versions/9f72f0dea908_clean_up_broken_heads.py
new file mode 100644
index 0000000..40cb7a8
--- /dev/null
+++ b/gitsrht/alembic/versions/9f72f0dea908_clean_up_broken_heads.py
@@ -0,0 +1,84 @@
+"""Clean up broken HEADs
+
+Revision ID: 9f72f0dea908
+Revises: 3c1285bb23e2
+Create Date: 2020-07-28 12:04:39.751225
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = '9f72f0dea908'
+down_revision = '3c1285bb23e2'
+
+import os.path
+import subprocess
+from alembic import op
+from sqlalchemy.orm import sessionmaker
+from pygit2 import GitError, Repository as GitRepository
+from gitsrht.types import Repository
+from srht.config import cfg
+try:
+    from tqdm import tqdm
+except ImportError:
+    def tqdm(iterable):
+        yield from iterable
+
+Session = sessionmaker()
+
+post_update = cfg("git.sr.ht", "post-update-script")
+
+
+def upgrade():
+    bind = op.get_bind()
+    session = Session(bind=bind)
+    print("Fixing repositories with broken HEADs")
+    for repo in tqdm(session.query(Repository).all()):
+        # Sometimes HEAD doesn't exist *at all*,
+        # some repositories are also plain uninitialised;
+        # git-init(1) says that running it on an existing repository is safe,
+        # so do that to try to sort out any unpleasantries
+        subprocess.run(["git", "-C", repo.path, "init", "--bare"],
+            stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
+        subprocess.run(["git", "-C", repo.path, "config", "srht.repo-id", str(repo.id)],
+            stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
+        subprocess.run(["git", "-C", repo.path, "config", "receive.denyDeleteCurrent", "ignore"],
+            stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
+        subprocess.run(["ln", "-f", "-s",
+                post_update,
+                os.path.join(repo.path, "hooks", "pre-receive")
+            ], stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
+        subprocess.run(["ln", "-f", "-s",
+                post_update,
+                os.path.join(repo.path, "hooks", "update")
+            ], stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
+        subprocess.run(["ln", "-f", "-s",
+                post_update,
+                os.path.join(repo.path, "hooks", "post-update")
+            ], stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
+
+        git_repo = GitRepository(repo.path)
+
+        try:
+            git_repo.lookup_reference("HEAD")
+        except GitError:
+            # Most likely "corrupted loose reference file: HEAD"
+            # This can happen if HEAD is zero-length for some reason,
+            # at this point no library solution will work
+            # and git(1) will refuse to acknowledge the repository
+            with open(os.path.join(repo.path, "HEAD"), "w") as head:
+                print("ref: refs/heads/master", file=head)
+
+        # Ensure that dangling HEAD (no default branch) is equivalent to
+        # no branches at all; if there are branches but HEAD is dangling,
+        # bake in the pre-0.55.0 behaviour of choosing the first branch
+        # in iteration order
+        if len(list(git_repo.branches.local)) != 0:
+            head = git_repo.lookup_reference("HEAD")
+            default_branch = git_repo.branches.get(head.target[len("refs/heads/"):])
+            if not default_branch:
+                branch = list(git_repo.branches.local)[0]
+                head.set_target(git_repo.branches[branch].name)
+
+
+def downgrade():
+    pass
-- 
2.38.4