Merge branch 'jk/no-looking-at-dotgit-outside-repo'

Update "git diff --no-index" codepath not to try to peek into .git/
directory that happens to be under the current directory, when we
know we are operating outside any repository.

* jk/no-looking-at-dotgit-outside-repo:
  diff: handle sha1 abbreviations outside of repository
  diff_aligned_abbrev: use "struct oid"
  diff_unique_abbrev: rename to diff_aligned_abbrev
  find_unique_abbrev: use 4-buffer ring
  test-*-cache-tree: setup git dir
  read info/{attributes,exclude} only when in repository

11 files changed, 66 insertions, 46 deletions

diff --git a/attr.c b/attr.c
index eec5d7d15a..1fcf042b87 100644
--- a/attr.c
+++ b/attr.c
@@ -531,7 +531,11 @@ static void bootstrap_attr_stack(void)
 		debug_push(elem);
 	}
 
-	elem = read_attr_from_file(git_path_info_attributes(), 1);
+	if (startup_info->have_repository)
+		elem = read_attr_from_file(git_path_info_attributes(), 1);
+	else
+		elem = NULL;
+
 	if (!elem)
 		elem = xcalloc(1, sizeof(*elem));
 	elem->origin = NULL;
diff --git a/builtin/merge.c b/builtin/merge.c
index a8b57c7d98..b65eeaa87d 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -1374,12 +1374,11 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 		struct commit *commit;
 
 		if (verbosity >= 0) {
-			char from[GIT_SHA1_HEXSZ + 1], to[GIT_SHA1_HEXSZ + 1];
-			find_unique_abbrev_r(from, head_commit->object.oid.hash,
-					      DEFAULT_ABBREV);
-			find_unique_abbrev_r(to, remoteheads->item->object.oid.hash,
-					      DEFAULT_ABBREV);
-			printf(_("Updating %s..%s\n"), from, to);
+			printf(_("Updating %s..%s\n"),
+			       find_unique_abbrev(head_commit->object.oid.hash,
+						  DEFAULT_ABBREV),
+			       find_unique_abbrev(remoteheads->item->object.oid.hash,
+						  DEFAULT_ABBREV));
 		}
 		strbuf_addstr(&msg, "Fast-forward");
 		if (have_message)
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index 04ed38e17d..680759d256 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -1163,10 +1163,6 @@ static void check_aliased_update(struct command *cmd, struct string_list *list)
 	struct string_list_item *item;
 	struct command *dst_cmd;
 	unsigned char sha1[GIT_SHA1_RAWSZ];
-	char cmd_oldh[GIT_SHA1_HEXSZ + 1],
-	     cmd_newh[GIT_SHA1_HEXSZ + 1],
-	     dst_oldh[GIT_SHA1_HEXSZ + 1],
-	     dst_newh[GIT_SHA1_HEXSZ + 1];
 	int flag;
 
 	strbuf_addf(&buf, "%s%s", get_git_namespace(), cmd->ref_name);
@@ -1197,14 +1193,14 @@ static void check_aliased_update(struct command *cmd, struct string_list *list)
 
 	dst_cmd->skip_update = 1;
 
-	find_unique_abbrev_r(cmd_oldh, cmd->old_sha1, DEFAULT_ABBREV);
-	find_unique_abbrev_r(cmd_newh, cmd->new_sha1, DEFAULT_ABBREV);
-	find_unique_abbrev_r(dst_oldh, dst_cmd->old_sha1, DEFAULT_ABBREV);
-	find_unique_abbrev_r(dst_newh, dst_cmd->new_sha1, DEFAULT_ABBREV);
 	rp_error("refusing inconsistent update between symref '%s' (%s..%s) and"
 		 " its target '%s' (%s..%s)",
-		 cmd->ref_name, cmd_oldh, cmd_newh,
-		 dst_cmd->ref_name, dst_oldh, dst_newh);
+		 cmd->ref_name,
+		 find_unique_abbrev(cmd->old_sha1, DEFAULT_ABBREV),
+		 find_unique_abbrev(cmd->new_sha1, DEFAULT_ABBREV),
+		 dst_cmd->ref_name,
+		 find_unique_abbrev(dst_cmd->old_sha1, DEFAULT_ABBREV),
+		 find_unique_abbrev(dst_cmd->new_sha1, DEFAULT_ABBREV));
 
 	cmd->error_string = dst_cmd->error_string =
 		"inconsistent aliased update";
diff --git a/cache.h b/cache.h
index b7f34b4ae6..1be6526d14 100644
--- a/cache.h
+++ b/cache.h
@@ -903,8 +903,8 @@ extern char *sha1_pack_index_name(const unsigned char *sha1);
  * The result will be at least `len` characters long, and will be NUL
  * terminated.
  *
- * The non-`_r` version returns a static buffer which will be overwritten by
- * subsequent calls.
+ * The non-`_r` version returns a static buffer which remains valid until 4
+ * more calls to find_unique_abbrev are made.
  *
  * The `_r` variant writes to a buffer supplied by the caller, which must be at
  * least `GIT_SHA1_HEXSZ + 1` bytes. The return value is the number of bytes
diff --git a/combine-diff.c b/combine-diff.c
index 8e2a577bdb..59501db99a 100644
--- a/combine-diff.c
+++ b/combine-diff.c
@@ -1203,9 +1203,9 @@ static void show_raw_diff(struct combine_diff_path *p, int num_parent, struct re
 
 		/* Show sha1's */
 		for (i = 0; i < num_parent; i++)
-			printf(" %s", diff_unique_abbrev(p->parent[i].oid.hash,
-							 opt->abbrev));
-		printf(" %s ", diff_unique_abbrev(p->oid.hash, opt->abbrev));
+			printf(" %s", diff_aligned_abbrev(&p->parent[i].oid,
+							  opt->abbrev));
+		printf(" %s ", diff_aligned_abbrev(&p->oid, opt->abbrev));
 	}
 
 	if (opt->output_format & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS)) {
diff --git a/diff.c b/diff.c
index 5a4e9b31ef..4c09314cc7 100644
--- a/diff.c
+++ b/diff.c
@@ -3096,6 +3096,21 @@ static int similarity_index(struct diff_filepair *p)
 	return p->score * 100 / MAX_SCORE;
 }
 
+static const char *diff_abbrev_oid(const struct object_id *oid, int abbrev)
+{
+	if (startup_info->have_repository)
+		return find_unique_abbrev(oid->hash, abbrev);
+	else {
+		char *hex = oid_to_hex(oid);
+		if (abbrev < 0)
+			abbrev = FALLBACK_DEFAULT_ABBREV;
+		if (abbrev > GIT_SHA1_HEXSZ)
+			die("BUG: oid abbreviation out of range: %d", abbrev);
+		hex[abbrev] = '\0';
+		return hex;
+	}
+}
+
 static void fill_metainfo(struct strbuf *msg,
 			  const char *name,
 			  const char *other,
@@ -3154,9 +3169,9 @@ static void fill_metainfo(struct strbuf *msg,
 			    (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
 				abbrev = 40;
 		}
-		strbuf_addf(msg, "%s%sindex %s..", line_prefix, set,
-			    find_unique_abbrev(one->oid.hash, abbrev));
-		strbuf_add_unique_abbrev(msg, two->oid.hash, abbrev);
+		strbuf_addf(msg, "%s%sindex %s..%s", line_prefix, set,
+			    diff_abbrev_oid(&one->oid, abbrev),
+			    diff_abbrev_oid(&two->oid, abbrev));
 		if (one->mode == two->mode)
 			strbuf_addf(msg, " %06o", one->mode);
 		strbuf_addf(msg, "%s\n", reset);
@@ -4157,18 +4172,15 @@ void diff_free_filepair(struct diff_filepair *p)
 	free(p);
 }
 
-/*
- * This is different from find_unique_abbrev() in that
- * it stuffs the result with dots for alignment.
- */
-const char *diff_unique_abbrev(const unsigned char *sha1, int len)
+const char *diff_aligned_abbrev(const struct object_id *oid, int len)
 {
 	int abblen;
 	const char *abbrev;
-	if (len == 40)
-		return sha1_to_hex(sha1);
 
-	abbrev = find_unique_abbrev(sha1, len);
+	if (len == GIT_SHA1_HEXSZ)
+		return oid_to_hex(oid);
+
+	abbrev = diff_abbrev_oid(oid, len);
 	abblen = strlen(abbrev);
 
 	/*
@@ -4190,15 +4202,16 @@ const char *diff_unique_abbrev(const unsigned char *sha1, int len)
 	 * the automatic sizing is supposed to give abblen that ensures
 	 * uniqueness across all objects (statistically speaking).
 	 */
-	if (abblen < 37) {
-		static char hex[41];
+	if (abblen < GIT_SHA1_HEXSZ - 3) {
+		static char hex[GIT_SHA1_HEXSZ + 1];
 		if (len < abblen && abblen <= len + 2)
 			xsnprintf(hex, sizeof(hex), "%s%.*s", abbrev, len+3-abblen, "..");
 		else
 			xsnprintf(hex, sizeof(hex), "%s...", abbrev);
 		return hex;
 	}
-	return sha1_to_hex(sha1);
+
+	return oid_to_hex(oid);
 }
 
 static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
@@ -4209,9 +4222,9 @@ static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
 	fprintf(opt->file, "%s", diff_line_prefix(opt));
 	if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
 		fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
-			diff_unique_abbrev(p->one->oid.hash, opt->abbrev));
+			diff_aligned_abbrev(&p->one->oid, opt->abbrev));
 		fprintf(opt->file, "%s ",
-			diff_unique_abbrev(p->two->oid.hash, opt->abbrev));
+			diff_aligned_abbrev(&p->two->oid, opt->abbrev));
 	}
 	if (p->score) {
 		fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
diff --git a/diff.h b/diff.h
index 25ae60d5ff..01afc70bd5 100644
--- a/diff.h
+++ b/diff.h
@@ -340,7 +340,11 @@ extern void diff_warn_rename_limit(const char *varname, int needed, int degraded
 #define DIFF_STATUS_FILTER_AON		'*'
 #define DIFF_STATUS_FILTER_BROKEN	'B'
 
-extern const char *diff_unique_abbrev(const unsigned char *, int);
+/*
+ * This is different from find_unique_abbrev() in that
+ * it stuffs the result with dots for alignment.
+ */
+extern const char *diff_aligned_abbrev(const struct object_id *sha1, int);
 
 /* do not report anything on removed paths */
 #define DIFF_SILENT_ON_REMOVED 01
diff --git a/dir.c b/dir.c
index f9412e0213..bfa8c8a9a5 100644
--- a/dir.c
+++ b/dir.c
@@ -2237,8 +2237,6 @@ static GIT_PATH_FUNC(git_path_info_exclude, "info/exclude")
 
 void setup_standard_excludes(struct dir_struct *dir)
 {
-	const char *path;
-
 	dir->exclude_per_dir = ".gitignore";
 
 	/* core.excludefile defaulting to $XDG_HOME/git/ignore */
@@ -2249,10 +2247,12 @@ void setup_standard_excludes(struct dir_struct *dir)
 					 dir->untracked ? &dir->ss_excludes_file : NULL);
 
 	/* per repository user preference */
-	path = git_path_info_exclude();
-	if (!access_or_warn(path, R_OK, 0))
-		add_excludes_from_file_1(dir, path,
-					 dir->untracked ? &dir->ss_info_exclude : NULL);
+	if (startup_info->have_repository) {
+		const char *path = git_path_info_exclude();
+		if (!access_or_warn(path, R_OK, 0))
+			add_excludes_from_file_1(dir, path,
+						 dir->untracked ? &dir->ss_info_exclude : NULL);
+	}
 }
 
 int remove_path(const char *name)
diff --git a/sha1_name.c b/sha1_name.c
index c71fc172f5..06409a3845 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -508,7 +508,9 @@ int find_unique_abbrev_r(char *hex, const unsigned char *sha1, int len)
 
 const char *find_unique_abbrev(const unsigned char *sha1, int len)
 {
-	static char hex[GIT_SHA1_HEXSZ + 1];
+	static int bufno;
+	static char hexbuffer[4][GIT_SHA1_HEXSZ + 1];
+	char *hex = hexbuffer[3 & ++bufno];
 	find_unique_abbrev_r(hex, sha1, len);
 	return hex;
 }
diff --git a/t/helper/test-dump-cache-tree.c b/t/helper/test-dump-cache-tree.c
index 44f3290258..7af116d49e 100644
--- a/t/helper/test-dump-cache-tree.c
+++ b/t/helper/test-dump-cache-tree.c
@@ -58,6 +58,7 @@ int cmd_main(int ac, const char **av)
 {
 	struct index_state istate;
 	struct cache_tree *another = cache_tree();
+	setup_git_directory();
 	if (read_cache() < 0)
 		die("unable to read index file");
 	istate = the_index;
diff --git a/t/helper/test-scrap-cache-tree.c b/t/helper/test-scrap-cache-tree.c
index 5b2fd09908..27fe0405b8 100644
--- a/t/helper/test-scrap-cache-tree.c
+++ b/t/helper/test-scrap-cache-tree.c
@@ -7,6 +7,7 @@ static struct lock_file index_lock;
 
 int cmd_main(int ac, const char **av)
 {
+	setup_git_directory();
 	hold_locked_index(&index_lock, 1);
 	if (read_cache() < 0)
 		die("unable to read index file");