From: Stefan Beller <sbeller@google.com>
To: git@vger.kernel.org
Cc: Stefan Beller <sbeller@google.com>
Subject: [PATCH 1/1] diffcore: add a filter to find a specific blob
Date: Thu, 7 Dec 2017 16:24:47 -0800 [thread overview]
Message-ID: <20171208002447.20261-2-sbeller@google.com> (raw)
In-Reply-To: <20171208002447.20261-1-sbeller@google.com>
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@google.com/
Signed-off-by: Stefan Beller <sbeller@google.com>
---
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
next prev parent reply other threads:[~2017-12-08 0:25 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-08 0:24 [PATCH 0/1] diffcore-blobfind Stefan Beller
2017-12-08 0:24 ` Stefan Beller [this message]
2017-12-08 9:34 ` [PATCH 1/1] diffcore: add a filter to find a specific blob Jeff King
2017-12-08 16:28 ` Ramsay Jones
2017-12-08 20:19 ` Jeff King
2017-12-08 20:39 ` Stefan Beller
2017-12-08 21:38 ` Jeff King
2017-12-08 15:04 ` Junio C Hamano
2017-12-08 17:21 ` Junio C Hamano
2017-12-08 21:11 ` Stefan Beller
2017-12-08 21:15 ` Junio C Hamano
2017-12-11 19:58 ` [PATCH 0/1] diff-core blobfind Stefan Beller
2017-12-11 19:58 ` [PATCH 1/1] diffcore: add a filter to find a specific blob Stefan Beller
2017-12-11 23:17 ` Junio C Hamano
2017-12-12 0:21 ` Stefan Beller
2017-12-12 1:24 ` [PATCH] " Stefan Beller
2017-12-12 18:36 ` Junio C Hamano
2017-12-14 21:22 ` Jonathan Nieder
2017-12-14 22:30 ` Stefan Beller
2017-12-14 22:52 ` Jonathan Nieder
2017-12-15 2:18 ` Junio C Hamano
2017-12-27 18:49 ` Stefan Beller
2017-12-27 18:59 ` Jonathan Nieder
2017-12-27 19:57 ` Junio C Hamano
2017-12-14 22:44 ` Junio C Hamano
-- strict thread matches above, loose matches on Subject: below --
2017-11-20 22:25 [PATCH 0/1] Teaching the diff machinery about blobfind [WAS: git describe <blob>] Stefan Beller
2017-11-20 22:25 ` [PATCH 1/1] diffcore: add a filter to find a specific blob Stefan Beller
2017-11-24 7:43 ` Junio C Hamano
2017-11-25 4:59 ` Junio C Hamano
2017-12-07 21:40 ` Junio C Hamano
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