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 <blob-id>` gives a description as '<commit-ish>:<path>'. 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@xxxxxxxxxx/ Signed-off-by: Stefan Beller <sbeller@xxxxxxxxxx> Signed-off-by: Junio C Hamano <gitster@xxxxxxxxx> --- Documentation/diff-options.txt | 10 +++++++ diff.c | 21 ++++++++++++- diff.h | 3 ++ diffcore-pickaxe.c | 14 +++++++-- revision.c | 3 ++ t/t4064-diff-oidfind.sh | 68 ++++++++++++++++++++++++++++++++++++++++++ 6 files changed, 115 insertions(+), 4 deletions(-) create mode 100755 t/t4064-diff-oidfind.sh diff --git a/Documentation/diff-options.txt b/Documentation/diff-options.txt index dd0dba5b1d..f9cf85db05 100644 --- a/Documentation/diff-options.txt +++ b/Documentation/diff-options.txt @@ -492,6 +492,15 @@ occurrences of that string did not change). See the 'pickaxe' entry in linkgit:gitdiffcore[7] for more information. +--find-object=<object-id>:: + Look for differences that change the number of occurrences of + the specified object. Similar to `-S`, just the argument is different + in that it doesn't search for a specific string but for a specific + object id. ++ +The object can be a blob or a submodule commit. It implies the `-t` option in +`git-log` to also find trees. + --pickaxe-all:: When `-S` or `-G` finds a change, show all the changes in that changeset, not just the files that contain the change @@ -500,6 +509,7 @@ information. --pickaxe-regex:: Treat the <string> given to `-S` as an extended POSIX regular expression to match. + endif::git-format-patch[] -O<orderfile>:: diff --git a/diff.c b/diff.c index 0763e89263..7acddaaee7 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 = ""; /* trigger pickaxe */ + 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) diff --git a/diff.h b/diff.h index 0fb18dd735..8fa2ad8e2d 100644 --- a/diff.h +++ b/diff.h @@ -7,6 +7,7 @@ #include "tree-walk.h" #include "pathspec.h" #include "object.h" +#include "oidset.h" struct rev_info; struct diff_options; @@ -174,6 +175,8 @@ struct diff_options { enum diff_words_type word_diff; enum diff_submodule_format submodule_format; + struct oidset *objfind; + /* this is set by diffcore for DIFF_FORMAT_PATCH */ int found_changes; diff --git a/diffcore-pickaxe.c b/diffcore-pickaxe.c index 9476bd2108..0d0c697ae7 100644 --- a/diffcore-pickaxe.c +++ b/diffcore-pickaxe.c @@ -124,13 +124,21 @@ static int pickaxe_match(struct diff_filepair *p, struct diff_options *o, mmfile_t mf1, mf2; int ret; - if (!o->pickaxe[0]) - return 0; - /* ignore unmerged */ if (!DIFF_FILE_VALID(p->one) && !DIFF_FILE_VALID(p->two)) return 0; + if (o->objfind) { + if ((DIFF_FILE_VALID(p->one) && + oidset_contains(o->objfind, &p->one->oid)) || + (DIFF_FILE_VALID(p->two) && + oidset_contains(o->objfind, &p->two->oid))) + return 1; + } + + if (!o->pickaxe[0]) + return 0; + if (o->flags.allow_textconv) { textconv_one = get_textconv(p->one); textconv_two = get_textconv(p->two); diff --git a/revision.c b/revision.c index e2e691dd5a..43bb6265cd 100644 --- a/revision.c +++ b/revision.c @@ -2412,6 +2412,9 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct s revs->diffopt.flags.follow_renames) revs->diff = 1; + if (revs->diffopt.objfind) + revs->simplify_history = 0; + if (revs->topo_order) revs->limited = 1; diff --git a/t/t4064-diff-oidfind.sh b/t/t4064-diff-oidfind.sh new file mode 100755 index 0000000000..3bdf317af8 --- /dev/null +++ b/t/t4064-diff-oidfind.sh @@ -0,0 +1,68 @@ +#!/bin/sh + +test_description='test finding specific blobs in the revision walking' +. ./test-lib.sh + +test_expect_success 'setup ' ' + git commit --allow-empty -m "empty initial commit" && + + echo "Hello, world!" >greeting && + git add greeting && + git commit -m "add the greeting blob" && # borrowed from Git from the Bottom Up + git tag -m "the blob" greeting $(git rev-parse HEAD:greeting) && + + echo asdf >unrelated && + git add unrelated && + git commit -m "unrelated history" && + + git revert HEAD^ && + + git commit --allow-empty -m "another unrelated commit" +' + +test_expect_success 'find the greeting blob' ' + cat >expect <<-EOF && + Revert "add the greeting blob" + add the greeting blob + EOF + + git log --format=%s --find-object=greeting^{blob} >actual && + + test_cmp expect actual +' + +test_expect_success 'setup a tree' ' + mkdir a && + echo asdf >a/file && + git add a/file && + git commit -m "add a file in a subdirectory" +' + +test_expect_success 'find a tree' ' + cat >expect <<-EOF && + add a file in a subdirectory + EOF + + git log --format=%s -t --find-object=HEAD:a >actual && + + test_cmp expect actual +' + +test_expect_success 'setup a submodule' ' + test_create_repo sub && + test_commit -C sub sub && + git submodule add ./sub sub && + git commit -a -m "add sub" +' + +test_expect_success 'find a submodule' ' + cat >expect <<-EOF && + add sub + EOF + + git log --format=%s --find-object=HEAD:sub >actual && + + test_cmp expect actual +' + +test_done -- 2.15.1.620.gb9897f4670-goog
