grep: stop looking at random places for .gitattributes

grep searches for .gitattributes using "name" field in struct
grep_source but that field is not real on-disk path name. For example,
"grep pattern rev" fills the field with "rev:path", and Git looks for
.gitattributes in the (non-existent but exploitable) path "rev:path"
instead of "path".

This patch passes real paths down to grep_source_load_driver() when:

 - grep on work tree
 - grep on the index
 - grep a commit (or a tag if it points to a commit)

so that these cases look up .gitattributes at proper paths.
.gitattributes lookup is disabled in all other cases.

Initial-work-by: Jeff King <peff@peff.net>
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

4 files changed, 51 insertions, 17 deletions

diff --git a/builtin/grep.c b/builtin/grep.c
index 0654e0b0f6..973b1f6e98 100644
--- a/builtin/grep.c
+++ b/builtin/grep.c
@@ -86,7 +86,7 @@ static pthread_cond_t cond_result;
 static int skip_first_line;
 
 static void add_work(struct grep_opt *opt, enum grep_source_type type,
-		     const char *name, const void *id)
+		     const char *name, const char *path, const void *id)
 {
 	grep_lock();
 
@@ -94,7 +94,7 @@ static void add_work(struct grep_opt *opt, enum grep_source_type type,
 		pthread_cond_wait(&cond_write, &grep_mutex);
 	}
 
-	grep_source_init(&todo[todo_end].source, type, name, id);
+	grep_source_init(&todo[todo_end].source, type, name, path, id);
 	if (opt->binary != GREP_BINARY_TEXT)
 		grep_source_load_driver(&todo[todo_end].source);
 	todo[todo_end].done = 0;
@@ -319,7 +319,8 @@ static void *lock_and_read_sha1_file(const unsigned char *sha1, enum object_type
 }
 
 static int grep_sha1(struct grep_opt *opt, const unsigned char *sha1,
-		     const char *filename, int tree_name_len)
+		     const char *filename, int tree_name_len,
+		     const char *path)
 {
 	struct strbuf pathbuf = STRBUF_INIT;
 
@@ -333,7 +334,7 @@ static int grep_sha1(struct grep_opt *opt, const unsigned char *sha1,
 
 #ifndef NO_PTHREADS
 	if (use_threads) {
-		add_work(opt, GREP_SOURCE_SHA1, pathbuf.buf, sha1);
+		add_work(opt, GREP_SOURCE_SHA1, pathbuf.buf, path, sha1);
 		strbuf_release(&pathbuf);
 		return 0;
 	} else
@@ -342,7 +343,7 @@ static int grep_sha1(struct grep_opt *opt, const unsigned char *sha1,
 		struct grep_source gs;
 		int hit;
 
-		grep_source_init(&gs, GREP_SOURCE_SHA1, pathbuf.buf, sha1);
+		grep_source_init(&gs, GREP_SOURCE_SHA1, pathbuf.buf, path, sha1);
 		strbuf_release(&pathbuf);
 		hit = grep_source(opt, &gs);
 
@@ -362,7 +363,7 @@ static int grep_file(struct grep_opt *opt, const char *filename)
 
 #ifndef NO_PTHREADS
 	if (use_threads) {
-		add_work(opt, GREP_SOURCE_FILE, buf.buf, filename);
+		add_work(opt, GREP_SOURCE_FILE, buf.buf, filename, filename);
 		strbuf_release(&buf);
 		return 0;
 	} else
@@ -371,7 +372,7 @@ static int grep_file(struct grep_opt *opt, const char *filename)
 		struct grep_source gs;
 		int hit;
 
-		grep_source_init(&gs, GREP_SOURCE_FILE, buf.buf, filename);
+		grep_source_init(&gs, GREP_SOURCE_FILE, buf.buf, filename, filename);
 		strbuf_release(&buf);
 		hit = grep_source(opt, &gs);
 
@@ -427,7 +428,7 @@ static int grep_cache(struct grep_opt *opt, const struct pathspec *pathspec, int
 		if (cached || (ce->ce_flags & CE_VALID) || ce_skip_worktree(ce)) {
 			if (ce_stage(ce))
 				continue;
-			hit |= grep_sha1(opt, ce->sha1, ce->name, 0);
+			hit |= grep_sha1(opt, ce->sha1, ce->name, 0, ce->name);
 		}
 		else
 			hit |= grep_file(opt, ce->name);
@@ -445,7 +446,8 @@ static int grep_cache(struct grep_opt *opt, const struct pathspec *pathspec, int
 }
 
 static int grep_tree(struct grep_opt *opt, const struct pathspec *pathspec,
-		     struct tree_desc *tree, struct strbuf *base, int tn_len)
+		     struct tree_desc *tree, struct strbuf *base, int tn_len,
+		     int check_attr)
 {
 	int hit = 0;
 	enum interesting match = entry_not_interesting;
@@ -466,7 +468,8 @@ static int grep_tree(struct grep_opt *opt, const struct pathspec *pathspec,
 		strbuf_add(base, entry.path, te_len);
 
 		if (S_ISREG(entry.mode)) {
-			hit |= grep_sha1(opt, entry.sha1, base->buf, tn_len);
+			hit |= grep_sha1(opt, entry.sha1, base->buf, tn_len,
+					 check_attr ? base->buf + tn_len : NULL);
 		}
 		else if (S_ISDIR(entry.mode)) {
 			enum object_type type;
@@ -481,7 +484,8 @@ static int grep_tree(struct grep_opt *opt, const struct pathspec *pathspec,
 
 			strbuf_addch(base, '/');
 			init_tree_desc(&sub, data, size);
-			hit |= grep_tree(opt, pathspec, &sub, base, tn_len);
+			hit |= grep_tree(opt, pathspec, &sub, base, tn_len,
+					 check_attr);
 			free(data);
 		}
 		strbuf_setlen(base, old_baselen);
@@ -496,7 +500,7 @@ static int grep_object(struct grep_opt *opt, const struct pathspec *pathspec,
 		       struct object *obj, const char *name)
 {
 	if (obj->type == OBJ_BLOB)
-		return grep_sha1(opt, obj->sha1, name, 0);
+		return grep_sha1(opt, obj->sha1, name, 0, NULL);
 	if (obj->type == OBJ_COMMIT || obj->type == OBJ_TREE) {
 		struct tree_desc tree;
 		void *data;
@@ -519,7 +523,8 @@ static int grep_object(struct grep_opt *opt, const struct pathspec *pathspec,
 			strbuf_addch(&base, ':');
 		}
 		init_tree_desc(&tree, data, size);
-		hit = grep_tree(opt, pathspec, &tree, &base, base.len);
+		hit = grep_tree(opt, pathspec, &tree, &base, base.len,
+				obj->type == OBJ_COMMIT);
 		strbuf_release(&base);
 		free(data);
 		return hit;
diff --git a/grep.c b/grep.c
index 898be6ebfa..70050d2078 100644
--- a/grep.c
+++ b/grep.c
@@ -1363,7 +1363,7 @@ int grep_buffer(struct grep_opt *opt, char *buf, unsigned long size)
 	struct grep_source gs;
 	int r;
 
-	grep_source_init(&gs, GREP_SOURCE_BUF, NULL, NULL);
+	grep_source_init(&gs, GREP_SOURCE_BUF, NULL, NULL, NULL);
 	gs.buf = buf;
 	gs.size = size;
 
@@ -1374,10 +1374,12 @@ int grep_buffer(struct grep_opt *opt, char *buf, unsigned long size)
 }
 
 void grep_source_init(struct grep_source *gs, enum grep_source_type type,
-		      const char *name, const void *identifier)
+		      const char *name, const char *path,
+		      const void *identifier)
 {
 	gs->type = type;
 	gs->name = name ? xstrdup(name) : NULL;
+	gs->path = path ? xstrdup(path) : NULL;
 	gs->buf = NULL;
 	gs->size = 0;
 	gs->driver = NULL;
@@ -1399,6 +1401,8 @@ void grep_source_clear(struct grep_source *gs)
 {
 	free(gs->name);
 	gs->name = NULL;
+	free(gs->path);
+	gs->path = NULL;
 	free(gs->identifier);
 	gs->identifier = NULL;
 	grep_source_clear_data(gs);
@@ -1491,7 +1495,8 @@ void grep_source_load_driver(struct grep_source *gs)
 		return;
 
 	grep_attr_lock();
-	gs->driver = userdiff_find_by_path(gs->name);
+	if (gs->path)
+		gs->driver = userdiff_find_by_path(gs->path);
 	if (!gs->driver)
 		gs->driver = userdiff_find_by_name("default");
 	grep_attr_unlock();
diff --git a/grep.h b/grep.h
index d66b19712c..1f32944be1 100644
--- a/grep.h
+++ b/grep.h
@@ -144,11 +144,13 @@ struct grep_source {
 	char *buf;
 	unsigned long size;
 
+	char *path; /* for attribute lookups */
 	struct userdiff_driver *driver;
 };
 
 void grep_source_init(struct grep_source *gs, enum grep_source_type type,
-		      const char *name, const void *identifier);
+		      const char *name, const char *path,
+		      const void *identifier);
 void grep_source_clear_data(struct grep_source *gs);
 void grep_source_clear(struct grep_source *gs);
 void grep_source_load_driver(struct grep_source *gs);
diff --git a/t/t7008-grep-binary.sh b/t/t7008-grep-binary.sh
index fd6410fc71..26f831984d 100755
--- a/t/t7008-grep-binary.sh
+++ b/t/t7008-grep-binary.sh
@@ -111,6 +111,28 @@ test_expect_success 'grep respects binary diff attribute' '
 	test_cmp expect actual
 '
 
+test_expect_success 'grep --cached respects binary diff attribute' '
+	git grep --cached text t >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'grep --cached respects binary diff attribute (2)' '
+	git add .gitattributes &&
+	rm .gitattributes &&
+	git grep --cached text t >actual &&
+	test_when_finished "git rm --cached .gitattributes" &&
+	test_when_finished "git checkout .gitattributes" &&
+	test_cmp expect actual
+'
+
+test_expect_success 'grep revision respects binary diff attribute' '
+	git commit -m new &&
+	echo "Binary file HEAD:t matches" >expect &&
+	git grep text HEAD -- t >actual &&
+	test_when_finished "git reset HEAD^" &&
+	test_cmp expect actual
+'
+
 test_expect_success 'grep respects not-binary diff attribute' '
 	echo binQary | q_to_nul >b &&
 	git add b &&