From 15af58c1adba431c216e2a45fa0d22944560ba02 Mon Sep 17 00:00:00 2001 From: Stefan Beller Date: Thu, 4 Jan 2018 14:50:42 -0800 Subject: diffcore: add a pickaxe option to find a specific blob Sometimes users are given a hash of an object and they want to identify it further (ex.: Use verify-pack to find the largest blobs, but what are these? or [1]) One might be tempted to extend git-describe to also work with blobs, such that `git describe ` gives a description as ':'. This was implemented at [2]; as seen by the sheer number of responses (>110), it turns out this is tricky to get right. The hard part to get right is picking the correct 'commit-ish' as that could be the commit that (re-)introduced the blob or the blob that removed the blob; the blob could exist in different branches. Junio hinted at a different approach of solving this problem, which this patch implements. Teach the diff machinery another flag for restricting the information to what is shown. For example: $ ./git log --oneline --find-object=v2.0.0:Makefile b2feb64309 Revert the whole "ask curl-config" topic for now 47fbfded53 i18n: only extract comments marked with "TRANSLATORS:" we observe that the Makefile as shipped with 2.0 was appeared in v1.9.2-471-g47fbfded53 and in v2.0.0-rc1-5-gb2feb6430b. The reason why these commits both occur prior to v2.0.0 are evil merges that are not found using this new mechanism. [1] https://stackoverflow.com/questions/223678/which-commit-has-this-blob [2] https://public-inbox.org/git/20171028004419.10139-1-sbeller@google.com/ Signed-off-by: Stefan Beller Signed-off-by: Junio C Hamano --- diff.c | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-) (limited to 'diff.c') diff --git a/diff.c b/diff.c index 5508745dc8..a872bdcac1 100644 --- a/diff.c +++ b/diff.c @@ -4082,6 +4082,7 @@ void diff_setup(struct diff_options *options) options->interhunkcontext = diff_interhunk_context_default; options->ws_error_highlight = ws_error_highlight_default; options->flags.rename_empty = 1; + options->objfind = NULL; /* pathchange left =NULL by default */ options->change = diff_change; @@ -4487,6 +4488,23 @@ static int parse_ws_error_highlight_opt(struct diff_options *opt, const char *ar return 1; } +static int parse_objfind_opt(struct diff_options *opt, const char *arg) +{ + struct object_id oid; + + if (get_oid(arg, &oid)) + return error("unable to resolve '%s'", arg); + + if (!opt->objfind) + opt->objfind = xcalloc(1, sizeof(*opt->objfind)); + + opt->pickaxe_opts |= DIFF_PICKAXE_KIND_OBJFIND; + opt->flags.recursive = 1; + opt->flags.tree_in_recursive = 1; + oidset_insert(opt->objfind, &oid); + return 1; +} + int diff_opt_parse(struct diff_options *options, const char **av, int ac, const char *prefix) { @@ -4736,7 +4754,8 @@ int diff_opt_parse(struct diff_options *options, else if ((argcount = short_opt('O', av, &optarg))) { options->orderfile = prefix_filename(prefix, optarg); return argcount; - } + } else if (skip_prefix(arg, "--find-object=", &arg)) + return parse_objfind_opt(options, arg); else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) { int offending = parse_diff_filter_opt(optarg, options); if (offending) -- cgit v1.2.1