commit-graph: free write-context entries before overwriting

When writing a split graph file, we replace the final element of the
commit_graph_hash_after and commit_graph_filenames_after arrays. But
since these are allocated strings, we need to free them before
overwriting to avoid leaking the old string.

Signed-off-by: Jeff King <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: peff

commit-graph.c

@@ -2065,9 +2065,11 @@ static int write_commit_graph_file(struct write_commit_graph_context *ctx)
 			free(graph_name);
 		}
 
+		free(ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 1]);
 		ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 1] = xstrdup(hash_to_hex(file_hash));
 		final_graph_name = get_split_graph_filename(ctx->odb,
 					ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 1]);
+		free(ctx->commit_graph_filenames_after[ctx->num_commit_graphs_after - 1]);
 		ctx->commit_graph_filenames_after[ctx->num_commit_graphs_after - 1] = final_graph_name;
 
 		result = rename(ctx->graph_name, final_graph_name);