lockfile API users: simplify and don't leak "path"

Fix a memory leak in code added in 6c622f9f0bb (commit-graph: write
commit-graph chains, 2019-06-18). We needed to free the "lock_name" if
we encounter errors, and the "graph_name" after we'd run unlink() on
it.

For the case of write_commit_graph_file() refactoring the code to free
the "lock_name" after we were done using the "struct lock_file lk"
would have made the control flow more complex. Luckily we can free the
"lock_file" right after the hold_lock_file_for_update() call, if it
makes use of "path" at all it'll have copied its contents to a "struct
strbuf" of its own.

While I'm at it let's fix code added in fb10ca5b543 (sparse-checkout:
write using lockfile, 2019-11-21) in write_patterns_and_update() to
avoid the same complexity that I thought I needed when I wrote the
initial fix for write_commit_graph_file(). We can free the
"sparse_filename" right after calling hold_lock_file_for_update(), we
don't need to wait until we're exiting the function to do so.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/sparse-checkout.c b/builtin/sparse-checkout.c
index 9c338d33ea263b5e6db619eab74bf6d0c3303364..270ad49c2b831d98a484361f7302b9733bfbcdb2 100644 (file)
--- a/builtin/sparse-checkout.c
+++ b/builtin/sparse-checkout.c
@@ -328,11 +328,11 @@ static int write_patterns_and_update(struct pattern_list *pl)
 
        fd = hold_lock_file_for_update(&lk, sparse_filename,
                                      LOCK_DIE_ON_ERROR);
+       free(sparse_filename);
 
        result = update_working_directory(pl);
        if (result) {
                rollback_lock_file(&lk);
-               free(sparse_filename);
                clear_pattern_list(pl);
                update_working_directory(NULL);
                return result;
@@ -348,7 +348,6 @@ static int write_patterns_and_update(struct pattern_list *pl)
        fflush(fp);
        commit_lock_file(&lk);
 
-       free(sparse_filename);
        clear_pattern_list(pl);
 
        return 0;

diff --git a/commit-graph.c b/commit-graph.c
index aab0b292774cabb49ba967207012b0898ba85b48..b8cde7ea27d6b3bd0cdbbc9591293c36d75bb126 100644 (file)
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -1854,6 +1854,7 @@ static int write_commit_graph_file(struct write_commit_graph_context *ctx)
 
                hold_lock_file_for_update_mode(&lk, lock_name,
                                               LOCK_DIE_ON_ERROR, 0444);
+               free(lock_name);
 
                fd = git_mkstemp_mode(ctx->graph_name, 0444);
                if (fd < 0) {
@@ -1978,6 +1979,7 @@ static int write_commit_graph_file(struct write_commit_graph_context *ctx)
                } else {
                        char *graph_name = get_commit_graph_filename(ctx->odb);
                        unlink(graph_name);
+                       free(graph_name);
                }
 
                ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 1] = xstrdup(hash_to_hex(file_hash));