[PATCH v2] commit-graph: fix UX issue when .lock file exists

From

Derrick Stolee <dstolee@microsoft.com>

Date

May 10, 2018, 17:42 UTC

Message-ID

<20180510174242.44346-1-dstolee@microsoft.com>

In-Reply-To

<20180509141523.89896-1-dstolee@microsoft.com>

The existing code does the following when acquiring the lock:

1. Try to acquire the lock.
2. If it fails, try to create the .git/object/info directory.
3. Try to acquire the lock, failing if necessary.

  "fatal: cannot mkdir .git/objects/info: File exists"

While technically this honors the lockfile, it does not help the user.

Instead, do the following:

1. Check for existence of .git/objects/info; create if necessary.
2. Try to acquire the lock, failing if necessary.

The new output looks like:

  fatal: Unable to create
  '<dir>/.git/objects/info/commit-graph.lock': File exists.

  Another git process seems to be running in this repository, e.g.
  an editor opened by 'git commit'. Please make sure all processes
  are terminated then try again. If it still fails, a git process
  may have crashed in this repository earlier:
  remove the file manually to continue.

Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
---
 commit-graph.c | 22 +++++-----------------
 1 file changed, 5 insertions(+), 17 deletions(-)

diff --git a/commit-graph.c b/commit-graph.c
index a8c337dd77..bb54c1214c 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -1,5 +1,6 @@
 #include "cache.h"
 #include "config.h"
+#include "dir.h"
 #include "git-compat-util.h"
 #include "lockfile.h"
 #include "pack.h"
@@ -640,7 +641,6 @@ void write_commit_graph(const char *obj_dir,
 	struct hashfile *f;
 	uint32_t i, count_distinct = 0;
 	char *graph_name;
-	int fd;
 	struct lock_file lk = LOCK_INIT;
 	uint32_t chunk_ids[5];
 	uint64_t chunk_offsets[5];
@@ -754,23 +754,11 @@ void write_commit_graph(const char *obj_dir,
 	compute_generation_numbers(&commits);
 
 	graph_name = get_commit_graph_filename(obj_dir);
-	fd = hold_lock_file_for_update(&lk, graph_name, 0);
-
-	if (fd < 0) {
-		struct strbuf folder = STRBUF_INIT;
-		strbuf_addstr(&folder, graph_name);
-		strbuf_setlen(&folder, strrchr(folder.buf, '/') - folder.buf);
-
-		if (mkdir(folder.buf, 0777) < 0)
-			die_errno(_("cannot mkdir %s"), folder.buf);
-		strbuf_release(&folder);
-
-		fd = hold_lock_file_for_update(&lk, graph_name, LOCK_DIE_ON_ERROR);
-
-		if (fd < 0)
-			die_errno("unable to create '%s'", graph_name);
-	}
+	if (safe_create_leading_directories(graph_name))
+		die_errno(_("unable to create leading directories of %s"),
+			  graph_name);
 
+	hold_lock_file_for_update(&lk, graph_name, LOCK_DIE_ON_ERROR);
 	f = hashfd(lk.tempfile->fd, lk.tempfile->filename.buf);
 
 	hashwrite_be32(f, GRAPH_SIGNATURE);

base-commit: 34fdd433396ee0e3ef4de02eb2189f8226eafe4e

-- 
2.16.2.329.gfb62395de6