Re: [PATCH 7/4] submodule: clarify logic in show_submodule_summary
From: Junio C Hamano <hidden>
Date: 2016-06-15 22:56:29
Jeff King [off-list ref] writes:
There are two uses of the "left" and "right" commit variables that make it hard to be sure what values they have (both for the reader, and for gcc, which wrongly complains that they might be used uninitialized). The functions starts with a cascading if statement, checking that the input sha1s exist, and finally working up to preparing a revision walk. We only prepare the walk if the cascading conditional did not find any problems, which we check by seeing whether it set the "message" variable or not. It's simpler and more obvious to just add a condition to the end of the cascade. Later, we check the same "message" variable when deciding whether to clear commit marks on the left/right commits; if it is set, we presumably never started the walk. This is wrong, though; we might have started the walk and munged commit flags, only to encounter an error afterwards. We should always clear the flags on left/right if they exist, whether the walk was successful or not. Signed-off-by: Jeff King <redacted> ---
Looks good. Thanks.
quoted hunk
submodule.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-)diff --git a/submodule.c b/submodule.c index 9ba1496..975bc87 100644 --- a/submodule.c +++ b/submodule.c@@ -261,7 +261,7 @@ void show_submodule_summary(FILE *f, const char *path, const char *del, const char *add, const char *reset) { struct rev_info rev; - struct commit *left = left, *right = right; + struct commit *left = NULL, *right = NULL; const char *message = NULL; struct strbuf sb = STRBUF_INIT; int fast_forward = 0, fast_backward = 0;@@ -275,10 +275,8 @@ void show_submodule_summary(FILE *f, const char *path, else if (!(left = lookup_commit_reference(one)) || !(right = lookup_commit_reference(two))) message = "(commits not present)"; - - if (!message && - prepare_submodule_summary(&rev, path, left, right, - &fast_forward, &fast_backward)) + else if (prepare_submodule_summary(&rev, path, left, right, + &fast_forward, &fast_backward)) message = "(revision walker failed)"; if (dirty_submodule & DIRTY_SUBMODULE_UNTRACKED)@@ -302,11 +300,12 @@ void show_submodule_summary(FILE *f, const char *path, strbuf_addf(&sb, "%s:%s\n", fast_backward ? " (rewind)" : "", reset); fwrite(sb.buf, sb.len, 1, f); - if (!message) { + if (!message) /* only NULL if we succeeded in setting up the walk */ print_submodule_summary(&rev, f, del, add, reset); + if (left) clear_commit_marks(left, ~0); + if (right) clear_commit_marks(right, ~0); - } strbuf_release(&sb); }