[PATCH] log_tree_diff: die when we fail to parse a commit
- From
Jeff King <peff@peff.net>
- Date
- Oct 6, 2013, 04:48 UTC
- Message-ID
- <20131006044856.GA12301@sigill.intra.peff.net>
We currently call parse_commit and then assume we can dereference the resulting "tree" struct field. If parsing failed, however, that field is NULL and we end up segfaulting.
Instead of a segfault, let's print an error message and die a little more gracefully.
Note that this should never happen in practice, but may happen in a corrupt repository (or when accessing objects not connected to the reachable history, whose parents may be subject to pruning).
Signed-off-by: Jeff King <peff@peff.net> --- Not a huge deal, since we are terminating the program either way. There are other places in the code with a bare parse_commit that could probably use the same treatment. I didn't investigate them, but they could easily build on the parse_commit_or_die here if somebody wants to follow up.
commit.c | 7 +++++++ commit.h | 1 + log-tree.c | 6 +++--- 3 files changed, 11 insertions(+), 3 deletions(-)
diff --git a/commit.c b/commit.c index de16a3c..51a9bbc 100644 --- a/commit.c +++ b/commit.c @@ -341,6 +341,13 @@ int parse_commit(struct commit *item) return ret; } +void parse_commit_or_die(struct commit *item) +{ + if (parse_commit(item)) + die("unable to parse commit %s", + item ? sha1_to_hex(item->object.sha1) : "(null)"); +} + int find_commit_subject(const char *commit_buffer, const char **subject) { const char *eol; diff --git a/commit.h b/commit.h index bd841f4..934af88 100644 --- a/commit.h +++ b/commit.h @@ -49,6 +49,7 @@ int parse_commit(struct commit *item); int parse_commit_buffer(struct commit *item, const void *buffer, unsigned long size); int parse_commit(struct commit *item); +void parse_commit_or_die(struct commit *item); /* Find beginning and length of commit subject. */ int find_commit_subject(const char *commit_buffer, const char **subject); diff --git a/log-tree.c b/log-tree.c index 8534d91..e958d07 100644 --- a/log-tree.c +++ b/log-tree.c @@ -734,7 +734,7 @@ static int log_tree_diff(struct rev_info *opt, struct commit *commit, struct log if (!opt->diff && !DIFF_OPT_TST(&opt->diffopt, EXIT_WITH_STATUS)) return 0; - parse_commit(commit); + parse_commit_or_die(commit); sha1 = commit->tree->object.sha1; /* Root commit? */ @@ -759,7 +759,7 @@ static int log_tree_diff(struct rev_info *opt, struct commit *commit, struct log * parent, showing summary diff of the others * we merged _in_. */ - parse_commit(parents->item); + parse_commit_or_die(parents->item); diff_tree_sha1(parents->item->tree->object.sha1, sha1, "", &opt->diffopt); log_tree_diff_flush(opt); @@ -774,7 +774,7 @@ static int log_tree_diff(struct rev_info *opt, struct commit *commit, struct log for (;;) { struct commit *parent = parents->item; - parse_commit(parent); + parse_commit_or_die(parent); diff_tree_sha1(parent->tree->object.sha1, sha1, "", &opt->diffopt); log_tree_diff_flush(opt);
-- 1.8.4.1.4.gf327177