On Sat, Feb 01, 2020 at 10:25:36PM +0100, Johannes Schindelin wrote:
> Hi,
>
> On Sat, 1 Feb 2020, SZEDER Gábor wrote:
>
> > On Thu, Jan 30, 2020 at 04:28:17PM -0800, Taylor Blau wrote:
> > > diff --git a/commit-graph.c b/commit-graph.c
> > > index 6d34829f57..02e6ad9d1f 100644
> > > --- a/commit-graph.c
> > > +++ b/commit-graph.c
> > > @@ -1565,15 +1565,18 @@ static void split_graph_merge_strategy(struct write_commit_graph_context *ctx)
> > > num_commits = ctx->commits.nr;
> > > ctx->num_commit_graphs_after = ctx->num_commit_graphs_before + 1;
> > >
> > > - while (g && (g->num_commits <= size_mult * num_commits ||
> > > - (max_commits && num_commits > max_commits))) {
> > > - if (g->odb != ctx->odb)
> > > - break;
> > > + if (ctx->split_opts->flags != COMMIT_GRAPH_SPLIT_MERGE_PROHIBITED) {
> >
> > This line segfaults in the tests 'fetch.writeCommitGraph' and
> > 'fetch.writeCommitGraph with submodules' in 't5510-fetch.sh', because
> > 'git fetch' doesn't pass a 'split_opts' to the commit-graph functions.
>
> I noticed the same. This patch seems to fix it for me:
>
> -- snip --
> diff --git a/commit-graph.c b/commit-graph.c
> index a5d7624073f..af5c58833cf 100644
> --- a/commit-graph.c
> +++ b/commit-graph.c
> @@ -1566,7 +1566,8 @@ static void split_graph_merge_strategy(struct write_commit_graph_context *ctx)
> num_commits = ctx->commits.nr;
> ctx->num_commit_graphs_after = ctx->num_commit_graphs_before + 1;
>
> - if (ctx->split_opts->flags != COMMIT_GRAPH_SPLIT_MERGE_PROHIBITED) {
> + if (ctx->split_opts &&
> + ctx->split_opts->flags != COMMIT_GRAPH_SPLIT_MERGE_PROHIBITED) {
> while (g && (g->num_commits <= size_mult * num_commits ||
> (max_commits && num_commits > max_commits) ||
> (ctx->split_opts->flags == COMMIT_GRAPH_SPLIT_MERGE_REQUIRED))) {
> -- snap --
Yeah, that's what I noted below, but I'm not sure that this is the
right solution. Why doesn't cmd_fetch() call
write_commit_graph_reachable() with a real 'split_opts' parameter in
the first place? Wouldn't it be better if it did?
> > Thread 1 "git" received signal SIGSEGV, Segmentation fault.
> > 0x00000000005113dd in split_graph_merge_strategy (ctx=0x9ca930)
> > at commit-graph.c:1568
> > 1568 if (ctx->split_opts->flags != COMMIT_GRAPH_SPLIT_MERGE_PROHIBITED) {
> > (gdb) p *ctx
> > $1 = {r = 0x9ae2a0 <the_repo>, odb = 0x9c0df0, graph_name = 0x0, oids = {
> > list = 0xa02660, nr = 12, alloc = 1024}, commits = {list = 0x9caa00,
> > nr = 6, alloc = 6}, num_extra_edges = 0, approx_nr_objects = 0,
> > progress = 0x0, progress_done = 0, progress_cnt = 0, base_graph_name = 0x0,
> > num_commit_graphs_before = 0, num_commit_graphs_after = 1,
> > commit_graph_filenames_before = 0x0, commit_graph_filenames_after = 0x0,
> > commit_graph_hash_after = 0x0, new_num_commits_in_base = 0,
> > new_base_graph = 0x0, append = 0, report_progress = 1, split = 1,
> > check_oids = 0, split_opts = 0x0}
> > ^^^^^^^^^^^^^^^^
> > (gdb) bt
> > #0 0x00000000005113dd in split_graph_merge_strategy (ctx=0x9ca930)
> > at commit-graph.c:1568
> > #1 0x0000000000512446 in write_commit_graph (odb=0x9c0df0, pack_indexes=0x0,
> > commit_hex=0x7fffffffd550,
> > flags=(COMMIT_GRAPH_WRITE_PROGRESS | COMMIT_GRAPH_WRITE_SPLIT),
> > split_opts=0x0) at commit-graph.c:1891
> > #2 0x000000000050fd86 in write_commit_graph_reachable (odb=0x9c0df0,
> > flags=(COMMIT_GRAPH_WRITE_PROGRESS | COMMIT_GRAPH_WRITE_SPLIT),
> > split_opts=0x0) at commit-graph.c:1174
> > ^^^^^^^^^^^^^^
> > #3 0x0000000000444ea4 in cmd_fetch (argc=0, argv=0x7fffffffd9b8, prefix=0x0)
> > at builtin/fetch.c:1873
> > #4 0x0000000000406154 in run_builtin (p=0x969a88 <commands+840>, argc=2,
> > argv=0x7fffffffd9b0) at git.c:444
> > #5 0x00000000004064a4 in handle_builtin (argc=2, argv=0x7fffffffd9b0)
> > at git.c:674
> > #6 0x000000000040674c in run_argv (argcp=0x7fffffffd84c, argv=0x7fffffffd840)
> > at git.c:741
> > #7 0x0000000000406bbd in cmd_main (argc=2, argv=0x7fffffffd9b0) at git.c:872
> > #8 0x00000000004cfd4e in main (argc=5, argv=0x7fffffffd998)
> > at common-main.c:52
> >
> > Note that this function split_graph_merge_strategy() does look at
> > various fields in 'ctx->split_opts' a bit earlier, but those accesses
> > are protected by a 'if (ctx->split_opts)' condition.
> > expire_commit_graphs() does the same.
> >
> >
> > > + while (g && (g->num_commits <= size_mult * num_commits ||
> > > + (max_commits && num_commits > max_commits) ||
> > > + (ctx->split_opts->flags == COMMIT_GRAPH_SPLIT_MERGE_REQUIRED))) {
> > > + if (g->odb != ctx->odb)
> > > + break;
> > >
> > > - num_commits += g->num_commits;
> > > - g = g->base_graph;
> > > + num_commits += g->num_commits;
> > > + g = g->base_graph;
> > >
> > > - ctx->num_commit_graphs_after--;
> > > + ctx->num_commit_graphs_after--;
> > > + }
> > > }
> > >
> >
