Merge branch 'jk/diff-blob'

The result from "git diff" that compares two blobs, e.g. "git diff
$commit1:$path $commit2:$path", used to be shown with the full
object name as given on the command line, but it is more natural to
use the $path in the output and use it to look up .gitattributes.

* jk/diff-blob:
  diff: use blob path for blob/file diffs
  diff: use pending "path" if it is available
  diff: use the word "path" instead of "name" for blobs
  diff: pass whole pending entry in blobinfo
  handle_revision_arg: record paths for pending objects
  handle_revision_arg: record modes for "a..b" endpoints
  t4063: add tests of direct blob diffs
  get_sha1_with_context: dynamically allocate oc->path
  get_sha1_with_context: always initialize oc->symlink_path
  sha1_name: consistently refer to object_context as "oc"
  handle_revision_arg: add handle_dotdot() helper
  handle_revision_arg: hoist ".." check out of range parsing
  handle_revision_arg: stop using "dotdot" as a generic pointer
  handle_revision_arg: simplify commit reference lookups
  handle_revision_arg: reset "dotdot" consistently

builtin/cat-file.c

@@ -61,7 +61,8 @@ static int cat_one_file(int opt, const char *exp_type, const char *obj_name,
 	if (unknown_type)
 		flags |= LOOKUP_UNKNOWN_OBJECT;
 
-	if (get_sha1_with_context(obj_name, 0, oid.hash, &obj_context))
+	if (get_sha1_with_context(obj_name, GET_SHA1_RECORD_PATH,
+				  oid.hash, &obj_context))
 		die("Not a valid object name %s", obj_name);
 
 	if (!path)
@@ -166,6 +167,7 @@ static int cat_one_file(int opt, const char *exp_type, const char *obj_name,
 
 	write_or_die(1, buf, size);
 	free(buf);
+	free(obj_context.path);
 	return 0;
 }
 

builtin/diff.c

@@ -20,23 +20,22 @@
 #define DIFF_NO_INDEX_EXPLICIT 1
 #define DIFF_NO_INDEX_IMPLICIT 2
 
-struct blobinfo {
-	struct object_id oid;
-	const char *name;
-	unsigned mode;
-};
-
 static const char builtin_diff_usage[] =
 "git diff [<options>] [<commit> [<commit>]] [--] [<path>...]";
 
+static const char *blob_path(struct object_array_entry *entry)
+{
+	return entry->path ? entry->path : entry->name;
+}
+
 static void stuff_change(struct diff_options *opt,
 			 unsigned old_mode, unsigned new_mode,
 			 const struct object_id *old_oid,
 			 const struct object_id *new_oid,
 			 int old_oid_valid,
 			 int new_oid_valid,
-			 const char *old_name,
-			 const char *new_name)
+			 const char *old_path,
+			 const char *new_path)
 {
 	struct diff_filespec *one, *two;
 
@@ -47,16 +46,16 @@ static void stuff_change(struct diff_options *opt,
 	if (DIFF_OPT_TST(opt, REVERSE_DIFF)) {
 		SWAP(old_mode, new_mode);
 		SWAP(old_oid, new_oid);
-		SWAP(old_name, new_name);
+		SWAP(old_path, new_path);
 	}
 
 	if (opt->prefix &&
-	    (strncmp(old_name, opt->prefix, opt->prefix_length) ||
-	     strncmp(new_name, opt->prefix, opt->prefix_length)))
+	    (strncmp(old_path, opt->prefix, opt->prefix_length) ||
+	     strncmp(new_path, opt->prefix, opt->prefix_length)))
 		return;
 
-	one = alloc_filespec(old_name);
-	two = alloc_filespec(new_name);
+	one = alloc_filespec(old_path);
+	two = alloc_filespec(new_path);
 	fill_filespec(one, old_oid->hash, old_oid_valid, old_mode);
 	fill_filespec(two, new_oid->hash, new_oid_valid, new_mode);
 
@@ -65,7 +64,7 @@ static void stuff_change(struct diff_options *opt,
 
 static int builtin_diff_b_f(struct rev_info *revs,
 			    int argc, const char **argv,
-			    struct blobinfo *blob)
+			    struct object_array_entry **blob)
 {
 	/* Blob vs file in the working tree*/
 	struct stat st;
@@ -84,39 +83,40 @@ static int builtin_diff_b_f(struct rev_info *revs,
 
 	diff_set_mnemonic_prefix(&revs->diffopt, "o/", "w/");
 
-	if (blob[0].mode == S_IFINVALID)
-		blob[0].mode = canon_mode(st.st_mode);
+	if (blob[0]->mode == S_IFINVALID)
+		blob[0]->mode = canon_mode(st.st_mode);
 
 	stuff_change(&revs->diffopt,
-		     blob[0].mode, canon_mode(st.st_mode),
-		     &blob[0].oid, &null_oid,
+		     blob[0]->mode, canon_mode(st.st_mode),
+		     &blob[0]->item->oid, &null_oid,
 		     1, 0,
-		     path, path);
+		     blob[0]->path ? blob[0]->path : path,
+		     path);
 	diffcore_std(&revs->diffopt);
 	diff_flush(&revs->diffopt);
 	return 0;
 }
 
 static int builtin_diff_blobs(struct rev_info *revs,
 			      int argc, const char **argv,
-			      struct blobinfo *blob)
+			      struct object_array_entry **blob)
 {
 	unsigned mode = canon_mode(S_IFREG | 0644);
 
 	if (argc > 1)
 		usage(builtin_diff_usage);
 
-	if (blob[0].mode == S_IFINVALID)
-		blob[0].mode = mode;
+	if (blob[0]->mode == S_IFINVALID)
+		blob[0]->mode = mode;
 
-	if (blob[1].mode == S_IFINVALID)
-		blob[1].mode = mode;
+	if (blob[1]->mode == S_IFINVALID)
+		blob[1]->mode = mode;
 
 	stuff_change(&revs->diffopt,
-		     blob[0].mode, blob[1].mode,
-		     &blob[0].oid, &blob[1].oid,
+		     blob[0]->mode, blob[1]->mode,
+		     &blob[0]->item->oid, &blob[1]->item->oid,
 		     1, 1,
-		     blob[0].name, blob[1].name);
+		     blob_path(blob[0]), blob_path(blob[1]));
 	diffcore_std(&revs->diffopt);
 	diff_flush(&revs->diffopt);
 	return 0;
@@ -259,7 +259,7 @@ int cmd_diff(int argc, const char **argv, const char *prefix)
 	struct rev_info rev;
 	struct object_array ent = OBJECT_ARRAY_INIT;
 	int blobs = 0, paths = 0;
-	struct blobinfo blob[2];
+	struct object_array_entry *blob[2];
 	int nongit = 0, no_index = 0;
 	int result = 0;
 
@@ -408,9 +408,7 @@ int cmd_diff(int argc, const char **argv, const char *prefix)
 		} else if (obj->type == OBJ_BLOB) {
 			if (2 <= blobs)
 				die(_("more than two blobs given: '%s'"), name);
-			oidcpy(&blob[blobs].oid, &obj->oid);
-			blob[blobs].name = name;
-			blob[blobs].mode = entry->mode;
+			blob[blobs] = entry;
 			blobs++;
 
 		} else {

builtin/grep.c

@@ -1190,7 +1190,8 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 			break;
 		}
 
-		if (get_sha1_with_context(arg, 0, oid.hash, &oc)) {
+		if (get_sha1_with_context(arg, GET_SHA1_RECORD_PATH,
+					  oid.hash, &oc)) {
 			if (seen_dashdash)
 				die(_("unable to resolve revision: %s"), arg);
 			break;
@@ -1200,6 +1201,7 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 		if (!seen_dashdash)
 			verify_non_filename(prefix, arg);
 		add_object_array_with_path(object, arg, &list, oc.mode, oc.path);
+		free(oc.path);
 	}
 
 	/*

builtin/log.c

@@ -483,16 +483,20 @@ static int show_blob_object(const struct object_id *oid, struct rev_info *rev, c
 	    !DIFF_OPT_TST(&rev->diffopt, ALLOW_TEXTCONV))
 		return stream_blob_to_fd(1, oid, NULL, 0);
 
-	if (get_sha1_with_context(obj_name, 0, oidc.hash, &obj_context))
+	if (get_sha1_with_context(obj_name, GET_SHA1_RECORD_PATH,
+				  oidc.hash, &obj_context))
 		die(_("Not a valid object name %s"), obj_name);
-	if (!obj_context.path[0] ||
-	    !textconv_object(obj_context.path, obj_context.mode, &oidc, 1, &buf, &size))
+	if (!obj_context.path ||
+	    !textconv_object(obj_context.path, obj_context.mode, &oidc, 1, &buf, &size)) {
+		free(obj_context.path);
 		return stream_blob_to_fd(1, oid, NULL, 0);
+	}
 
 	if (!buf)
 		die(_("git show %s: bad file"), obj_name);
 
 	write_or_die(1, buf, size);
+	free(obj_context.path);
 	return 0;
 }
 

cache.h

@@ -1334,13 +1334,18 @@ static inline int hex2chr(const char *s)
 
 struct object_context {
 	unsigned char tree[20];
-	char path[PATH_MAX];
 	unsigned mode;
 	/*
 	 * symlink_path is only used by get_tree_entry_follow_symlinks,
 	 * and only for symlinks that point outside the repository.
 	 */
 	struct strbuf symlink_path;
+	/*
+	 * If GET_SHA1_RECORD_PATH is set, this will record path (if any)
+	 * found when resolving the name. The caller is responsible for
+	 * releasing the memory.
+	 */
+	char *path;
 };
 
 #define GET_SHA1_QUIETLY           01
@@ -1350,6 +1355,7 @@ struct object_context {
 #define GET_SHA1_TREEISH          020
 #define GET_SHA1_BLOB             040
 #define GET_SHA1_FOLLOW_SYMLINKS 0100
+#define GET_SHA1_RECORD_PATH     0200
 #define GET_SHA1_ONLY_TO_DIE    04000
 
 #define GET_SHA1_DISAMBIGUATORS \
@@ -1364,7 +1370,7 @@ extern int get_sha1_tree(const char *str, unsigned char *sha1);
 extern int get_sha1_treeish(const char *str, unsigned char *sha1);
 extern int get_sha1_blob(const char *str, unsigned char *sha1);
 extern void maybe_die_on_misspelt_object_name(const char *name, const char *prefix);
-extern int get_sha1_with_context(const char *str, unsigned flags, unsigned char *sha1, struct object_context *orc);
+extern int get_sha1_with_context(const char *str, unsigned flags, unsigned char *sha1, struct object_context *oc);
 
 extern int get_oid(const char *str, struct object_id *oid);