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 --blobfind=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 introduced in v1.9.2-471-g47fbfded53 and replaced in v2.0.0-rc1-5-gb2feb64309 by a different blob. [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> --- Documentation/diff-options.txt | 5 +++++ Makefile | 1 + builtin/log.c | 2 +- diff.c | 20 +++++++++++++++++++- diff.h | 3 +++ diffcore-blobfind.c | 41 +++++++++++++++++++++++++++++++++++++++++ diffcore.h | 1 + revision.c | 5 ++++- t/t4064-diff-blobfind.sh | 35 +++++++++++++++++++++++++++++++++++ 9 files changed, 110 insertions(+), 3 deletions(-) create mode 100644 diffcore-blobfind.c create mode 100755 t/t4064-diff-blobfind.sh diff --git a/Documentation/diff-options.txt b/Documentation/diff-options.txt index dd0dba5b1d..34d53b95f1 100644 --- a/Documentation/diff-options.txt +++ b/Documentation/diff-options.txt @@ -500,6 +500,11 @@ information. --pickaxe-regex:: Treat the <string> given to `-S` as an extended POSIX regular expression to match. + +--blobfind=<blob-id>:: + Restrict the output such that one side of the diff + matches the given blob-id. + endif::git-format-patch[] -O<orderfile>:: diff --git a/Makefile b/Makefile index ee9d5eb11e..fdfa8f38f6 100644 --- a/Makefile +++ b/Makefile @@ -775,6 +775,7 @@ LIB_OBJS += date.o LIB_OBJS += decorate.o LIB_OBJS += diffcore-break.o LIB_OBJS += diffcore-delta.o +LIB_OBJS += diffcore-blobfind.o LIB_OBJS += diffcore-order.o LIB_OBJS += diffcore-pickaxe.o LIB_OBJS += diffcore-rename.o diff --git a/builtin/log.c b/builtin/log.c index 6c1fa896ad..7b91f61423 100644 --- a/builtin/log.c +++ b/builtin/log.c @@ -181,7 +181,7 @@ static void cmd_log_init_finish(int argc, const char **argv, const char *prefix, init_display_notes(&rev->notes_opt); if (rev->diffopt.pickaxe || rev->diffopt.filter || - rev->diffopt.flags.follow_renames) + rev->diffopt.flags.follow_renames || rev->diffopt.blobfind) rev->always_show_header = 0; if (source) diff --git a/diff.c b/diff.c index 0763e89263..8861f89ab1 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->blobfind = NULL; /* pathchange left =NULL by default */ options->change = diff_change; @@ -4487,6 +4488,19 @@ static int parse_ws_error_highlight_opt(struct diff_options *opt, const char *ar return 1; } +static int parse_blobfind_opt(struct diff_options *opt, const char *arg) +{ + struct object_id oid; + + if (get_oid_blob(arg, &oid) || sha1_object_info(oid.hash, NULL) != OBJ_BLOB) + return error("object '%s' is not a blob", arg); + + if (!opt->blobfind) + opt->blobfind = xcalloc(1, sizeof(*opt->blobfind)); + oidset_insert(opt->blobfind, &oid); + return 1; +} + int diff_opt_parse(struct diff_options *options, const char **av, int ac, const char *prefix) { @@ -4736,7 +4750,8 @@ 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, "--blobfind=", &arg)) + return parse_blobfind_opt(options, arg); else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) { int offending = parse_diff_filter_opt(optarg, options); if (offending) @@ -5770,6 +5785,9 @@ void diffcore_std(struct diff_options *options) diffcore_skip_stat_unmatch(options); if (!options->found_follow) { /* See try_to_follow_renames() in tree-diff.c */ + + if (options->blobfind) + diffcore_blobfind(options); if (options->break_opt != -1) diffcore_break(options->break_opt); if (options->detect_rename) diff --git a/diff.h b/diff.h index 0fb18dd735..9178e498fa 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 *blobfind; + /* this is set by diffcore for DIFF_FORMAT_PATCH */ int found_changes; diff --git a/diffcore-blobfind.c b/diffcore-blobfind.c new file mode 100644 index 0000000000..e65c7cad6e --- /dev/null +++ b/diffcore-blobfind.c @@ -0,0 +1,41 @@ +/* + * Copyright (c) 2017 Google Inc. + */ +#include "cache.h" +#include "diff.h" +#include "diffcore.h" + +static void diffcore_filter_blobs(struct diff_queue_struct *q, + struct diff_options *options) +{ + int src, dst; + + if (!options->blobfind) + BUG("blobfind oidset not initialized???"); + + for (src = dst = 0; src < q->nr; src++) { + struct diff_filepair *p = q->queue[src]; + + if ((DIFF_FILE_VALID(p->one) && + oidset_contains(options->blobfind, &p->one->oid)) || + (DIFF_FILE_VALID(p->two) && + oidset_contains(options->blobfind, &p->two->oid))) { + q->queue[dst] = p; + dst++; + } else { + diff_free_filepair(p); + } + } + + if (!dst) { + free(q->queue); + DIFF_QUEUE_CLEAR(q); + } else { + q->nr = dst; + } +} + +void diffcore_blobfind(struct diff_options *options) +{ + diffcore_filter_blobs(&diff_queued_diff, options); +} diff --git a/diffcore.h b/diffcore.h index a30da161da..431917672f 100644 --- a/diffcore.h +++ b/diffcore.h @@ -107,6 +107,7 @@ extern struct diff_filepair *diff_queue(struct diff_queue_struct *, struct diff_filespec *); extern void diff_q(struct diff_queue_struct *, struct diff_filepair *); +extern void diffcore_blobfind(struct diff_options *); extern void diffcore_break(int); extern void diffcore_rename(struct diff_options *); extern void diffcore_merge_broken(void); diff --git a/revision.c b/revision.c index e2e691dd5a..8e1a89f832 100644 --- a/revision.c +++ b/revision.c @@ -2409,7 +2409,8 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct s /* Pickaxe, diff-filter and rename following need diffs */ if (revs->diffopt.pickaxe || revs->diffopt.filter || - revs->diffopt.flags.follow_renames) + revs->diffopt.flags.follow_renames || + revs->diffopt.blobfind) revs->diff = 1; if (revs->topo_order) @@ -2883,6 +2884,8 @@ int prepare_revision_walk(struct rev_info *revs) simplify_merges(revs); if (revs->children.name) set_children(revs); + if (revs->diffopt.blobfind) + revs->simplify_history = 0; return 0; } diff --git a/t/t4064-diff-blobfind.sh b/t/t4064-diff-blobfind.sh new file mode 100755 index 0000000000..b2c2964d77 --- /dev/null +++ b/t/t4064-diff-blobfind.sh @@ -0,0 +1,35 @@ +#!/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 --abbrev=12 --oneline --blobfind=greeting^{blob} >actual.raw && + cut -c 14- actual.raw >actual && + + test_cmp expect actual +' + +test_done -- 2.15.1.424.g9478a66081-goog
