Merge branch 'mh/check-ref-format-3'

* mh/check-ref-format-3: (23 commits)
  add_ref(): verify that the refname is formatted correctly
  resolve_ref(): expand documentation
  resolve_ref(): also treat a too-long SHA1 as invalid
  resolve_ref(): emit warnings for improperly-formatted references
  resolve_ref(): verify that the input refname has the right format
  remote: avoid passing NULL to read_ref()
  remote: use xstrdup() instead of strdup()
  resolve_ref(): do not follow incorrectly-formatted symbolic refs
  resolve_ref(): extract a function get_packed_ref()
  resolve_ref(): turn buffer into a proper string as soon as possible
  resolve_ref(): only follow a symlink that contains a valid, normalized refname
  resolve_ref(): use prefixcmp()
  resolve_ref(): explicitly fail if a symlink is not readable
  Change check_refname_format() to reject unnormalized refnames
  Inline function refname_format_print()
  Make collapse_slashes() allocate memory for its result
  Do not allow ".lock" at the end of any refname component
  Refactor check_refname_format()
  Change check_ref_format() to take a flags argument
  Change bad_ref_char() to return a boolean value
  ...

24 files changed, 426 insertions, 225 deletions

diff --git a/Documentation/git-check-ref-format.txt b/Documentation/git-check-ref-format.txt
index c9fdf84a0..103e7b128 100644
--- a/Documentation/git-check-ref-format.txt
+++ b/Documentation/git-check-ref-format.txt
@@ -8,8 +8,9 @@ git-check-ref-format - Ensures that a reference name is well formed
 SYNOPSIS
 --------
 [verse]
-'git check-ref-format' <refname>
-'git check-ref-format' --print <refname>
+'git check-ref-format' [--normalize]
+       [--[no-]allow-onelevel] [--refspec-pattern]
+       <refname>
 'git check-ref-format' --branch <branchname-shorthand>
 
 DESCRIPTION
@@ -28,22 +29,28 @@ git imposes the following rules on how references are named:
 
 . They can include slash `/` for hierarchical (directory)
   grouping, but no slash-separated component can begin with a
-  dot `.`.
+  dot `.` or end with the sequence `.lock`.
 
 . They must contain at least one `/`. This enforces the presence of a
   category like `heads/`, `tags/` etc. but the actual names are not
-  restricted.
+  restricted.  If the `--allow-onelevel` option is used, this rule
+  is waived.
 
 . They cannot have two consecutive dots `..` anywhere.
 
 . They cannot have ASCII control characters (i.e. bytes whose
   values are lower than \040, or \177 `DEL`), space, tilde `~`,
-  caret `{caret}`, colon `:`, question-mark `?`, asterisk `*`,
-  or open bracket `[` anywhere.
+  caret `{caret}`, or colon `:` anywhere.
 
-. They cannot end with a slash `/` nor a dot `.`.
+. They cannot have question-mark `?`, asterisk `{asterisk}`, or open
+  bracket `[` anywhere.  See the `--refspec-pattern` option below for
+  an exception to this rule.
 
-. They cannot end with the sequence `.lock`.
+. They cannot begin or end with a slash `/` or contain multiple
+  consecutive slashes (see the `--normalize` option below for an
+  exception to this rule)
+
+. They cannot end with a dot `.`.
 
 . They cannot contain a sequence `@{`.
 
@@ -68,16 +75,36 @@ reference name expressions (see linkgit:gitrevisions[7]):
 
 . at-open-brace `@{` is used as a notation to access a reflog entry.
 
-With the `--print` option, if 'refname' is acceptable, it prints the
-canonicalized name of a hypothetical reference with that name.  That is,
-it prints 'refname' with any extra `/` characters removed.
-
 With the `--branch` option, it expands the ``previous branch syntax''
 `@{-n}`.  For example, `@{-1}` is a way to refer the last branch you
 were on.  This option should be used by porcelains to accept this
 syntax anywhere a branch name is expected, so they can act as if you
 typed the branch name.
 
+OPTIONS
+-------
+--allow-onelevel::
+--no-allow-onelevel::
+	Controls whether one-level refnames are accepted (i.e.,
+	refnames that do not contain multiple `/`-separated
+	components).  The default is `--no-allow-onelevel`.
+
+--refspec-pattern::
+	Interpret <refname> as a reference name pattern for a refspec
+	(as used with remote repositories).  If this option is
+	enabled, <refname> is allowed to contain a single `{asterisk}`
+	in place of a one full pathname component (e.g.,
+	`foo/{asterisk}/bar` but not `foo/bar{asterisk}`).
+
+--normalize::
+	Normalize 'refname' by removing any leading slash (`/`)
+	characters and collapsing runs of adjacent slashes between
+	name components into a single slash.  Iff the normalized
+	refname is valid then print it to standard output and exit
+	with a status of 0.  (`--print` is a deprecated way to spell
+	`--normalize`.)
+
+
 EXAMPLES
 --------
 
@@ -90,7 +117,7 @@ $ git check-ref-format --branch @{-1}
 * Determine the reference name to use for a new branch:
 +
 ------------
-$ ref=$(git check-ref-format --print "refs/heads/$newbranch") ||
+$ ref=$(git check-ref-format --normalize "refs/heads/$newbranch") ||
 die "we do not like '$newbranch' as a branch name."
 ------------
 
diff --git a/builtin/check-ref-format.c b/builtin/check-ref-format.c
index 0723cf245..28a732027 100644
--- a/builtin/check-ref-format.c
+++ b/builtin/check-ref-format.c
@@ -8,29 +8,32 @@
 #include "strbuf.h"
 
 static const char builtin_check_ref_format_usage[] =
-"git check-ref-format [--print] <refname>\n"
+"git check-ref-format [--normalize] [options] <refname>\n"
 "   or: git check-ref-format --branch <branchname-shorthand>";
 
 /*
- * Remove leading slashes and replace each run of adjacent slashes in
- * src with a single slash, and write the result to dst.
+ * Return a copy of refname but with leading slashes removed and runs
+ * of adjacent slashes replaced with single slashes.
  *
  * This function is similar to normalize_path_copy(), but stripped down
  * to meet check_ref_format's simpler needs.
  */
-static void collapse_slashes(char *dst, const char *src)
+static char *collapse_slashes(const char *refname)
 {
+	char *ret = xmalloc(strlen(refname) + 1);
 	char ch;
 	char prev = '/';
+	char *cp = ret;
 
-	while ((ch = *src++) != '\0') {
+	while ((ch = *refname++) != '\0') {
 		if (prev == '/' && ch == prev)
 			continue;
 
-		*dst++ = ch;
+		*cp++ = ch;
 		prev = ch;
 	}
-	*dst = '\0';
+	*cp = '\0';
+	return ret;
 }
 
 static int check_ref_format_branch(const char *arg)
@@ -45,27 +48,41 @@ static int check_ref_format_branch(const char *arg)
 	return 0;
 }
 
-static int check_ref_format_print(const char *arg)
-{
-	char *refname = xmalloc(strlen(arg) + 1);
-
-	if (check_ref_format(arg))
-		return 1;
-	collapse_slashes(refname, arg);
-	printf("%s\n", refname);
-	return 0;
-}
-
 int cmd_check_ref_format(int argc, const char **argv, const char *prefix)
 {
+	int i;
+	int normalize = 0;
+	int flags = 0;
+	const char *refname;
+
 	if (argc == 2 && !strcmp(argv[1], "-h"))
 		usage(builtin_check_ref_format_usage);
 
 	if (argc == 3 && !strcmp(argv[1], "--branch"))
 		return check_ref_format_branch(argv[2]);
-	if (argc == 3 && !strcmp(argv[1], "--print"))
-		return check_ref_format_print(argv[2]);
-	if (argc != 2)
+
+	for (i = 1; i < argc && argv[i][0] == '-'; i++) {
+		if (!strcmp(argv[i], "--normalize") || !strcmp(argv[i], "--print"))
+			normalize = 1;
+		else if (!strcmp(argv[i], "--allow-onelevel"))
+			flags |= REFNAME_ALLOW_ONELEVEL;
+		else if (!strcmp(argv[i], "--no-allow-onelevel"))
+			flags &= ~REFNAME_ALLOW_ONELEVEL;
+		else if (!strcmp(argv[i], "--refspec-pattern"))
+			flags |= REFNAME_REFSPEC_PATTERN;
+		else
+			usage(builtin_check_ref_format_usage);
+	}
+	if (! (i == argc - 1))
 		usage(builtin_check_ref_format_usage);
-	return !!check_ref_format(argv[1]);
+
+	refname = argv[i];
+	if (normalize)
+		refname = collapse_slashes(refname);
+	if (check_refname_format(refname, flags))
+		return 1;
+	if (normalize)
+		printf("%s\n", refname);
+
+	return 0;
 }
diff --git a/builtin/checkout.c b/builtin/checkout.c
index 8210ccc13..04df4d786 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -871,7 +871,7 @@ static int parse_branchname_arg(int argc, const char **argv,
 	new->name = arg;
 	setup_branch_path(new);
 
-	if (check_ref_format(new->path) == CHECK_REF_FORMAT_OK &&
+	if (!check_refname_format(new->path, 0) &&
 	    resolve_ref(new->path, branch_rev, 1, NULL))
 		hashcpy(rev, branch_rev);
 	else
diff --git a/builtin/fetch-pack.c b/builtin/fetch-pack.c
index c8bf9b85b..c6bc8eb0a 100644
--- a/builtin/fetch-pack.c
+++ b/builtin/fetch-pack.c
@@ -546,7 +546,7 @@ static void filter_refs(struct ref **refs, int nr_match, char **match)
 	for (ref = *refs; ref; ref = next) {
 		next = ref->next;
 		if (!memcmp(ref->name, "refs/", 5) &&
-		    check_ref_format(ref->name + 5))
+		    check_refname_format(ref->name + 5, 0))
 			; /* trash */
 		else if (args.fetch_all &&
 			 (!args.depth || prefixcmp(ref->name, "refs/tags/") )) {
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index c1c5bac79..e2d3f9466 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -396,7 +396,7 @@ static const char *update(struct command *cmd)
 	struct ref_lock *lock;
 
 	/* only refs/... are allowed */
-	if (prefixcmp(name, "refs/") || check_ref_format(name + 5)) {
+	if (prefixcmp(name, "refs/") || check_refname_format(name + 5, 0)) {
 		rp_error("refusing to create funny ref '%s' remotely", name);
 		return "funny refname";
 	}
diff --git a/builtin/replace.c b/builtin/replace.c
index fe3a647a3..517fa1031 100644
--- a/builtin/replace.c
+++ b/builtin/replace.c
@@ -94,7 +94,7 @@ static int replace_object(const char *object_ref, const char *replace_ref,
 		     "refs/replace/%s",
 		     sha1_to_hex(object)) > sizeof(ref) - 1)
 		die("replace ref name too long: %.*s...", 50, ref);
-	if (check_ref_format(ref))
+	if (check_refname_format(ref, 0))
 		die("'%s' is not a valid ref name.", ref);
 
 	if (!resolve_ref(ref, prev, 1, NULL))
diff --git a/builtin/show-ref.c b/builtin/show-ref.c
index 45f0340c3..fafb6dd50 100644
--- a/builtin/show-ref.c
+++ b/builtin/show-ref.c
@@ -145,7 +145,7 @@ static int exclude_existing(const char *match)
 			if (strncmp(ref, match, matchlen))
 				continue;
 		}
-		if (check_ref_format(ref)) {
+		if (check_refname_format(ref, 0)) {
 			warning("ref '%s' ignored", ref);
 			continue;
 		}
diff --git a/builtin/tag.c b/builtin/tag.c
index 9d8961686..9b6fd9549 100644
--- a/builtin/tag.c
+++ b/builtin/tag.c
@@ -407,12 +407,12 @@ static int parse_msg_arg(const struct option *opt, const char *arg, int unset)
 static int strbuf_check_tag_ref(struct strbuf *sb, const char *name)
 {
 	if (name[0] == '-')
-		return CHECK_REF_FORMAT_ERROR;
+		return -1;
 
 	strbuf_reset(sb);
 	strbuf_addf(sb, "refs/tags/%s", name);
 
-	return check_ref_format(sb->buf);
+	return check_refname_format(sb->buf, 0);
 }
 
 int cmd_tag(int argc, const char **argv, const char *prefix)
diff --git a/cache.h b/cache.h
index 1aa682d83..e39e16001 100644
--- a/cache.h
+++ b/cache.h
@@ -819,10 +819,51 @@ static inline int get_sha1_with_context(const char *str, unsigned char *sha1, st
 {
 	return get_sha1_with_context_1(str, sha1, orc, 0, NULL);
 }
+
+/*
+ * Try to read a SHA1 in hexadecimal format from the 40 characters
+ * starting at hex.  Write the 20-byte result to sha1 in binary form.
+ * Return 0 on success.  Reading stops if a NUL is encountered in the
+ * input, so it is safe to pass this function an arbitrary
+ * null-terminated string.
+ */
 extern int get_sha1_hex(const char *hex, unsigned char *sha1);
+
 extern char *sha1_to_hex(const unsigned char *sha1);	/* static buffer result! */
 extern int read_ref(const char *filename, unsigned char *sha1);
-extern const char *resolve_ref(const char *path, unsigned char *sha1, int, int *);
+
+/*
+ * Resolve a reference, recursively following symbolic refererences.
+ *
+ * Store the referred-to object's name in sha1 and return the name of
+ * the non-symbolic reference that ultimately pointed at it.  The
+ * return value, if not NULL, is a pointer into either a static buffer
+ * or the input ref.
+ *
+ * If the reference cannot be resolved to an object, the behavior
+ * depends on the "reading" argument:
+ *
+ * - If reading is set, return NULL.
+ *
+ * - If reading is not set, clear sha1 and return the name of the last
+ *   reference name in the chain, which will either be a non-symbolic
+ *   reference or an undefined reference.  If this is a prelude to
+ *   "writing" to the ref, the return value is the name of the ref
+ *   that will actually be created or changed.
+ *
+ * If flag is non-NULL, set the value that it points to the
+ * combination of REF_ISPACKED (if the reference was found among the
+ * packed references) and REF_ISSYMREF (if the initial reference was a
+ * symbolic reference).
+ *
+ * If ref is not a properly-formatted, normalized reference, return
+ * NULL.  If more than MAXDEPTH recursive symbolic lookups are needed,
+ * give up and return NULL.
+ *
+ * errno is sometimes set on errors, but not always.
+ */
+extern const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *flag);
+
 extern int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref);
 extern int dwim_log(const char *str, int len, unsigned char *sha1, char **ref);
 extern int interpret_branch_name(const char *str, struct strbuf *);
diff --git a/connect.c b/connect.c
index ee1d4b4b4..51990fa0c 100644
--- a/connect.c
+++ b/connect.c
@@ -22,7 +22,7 @@ static int check_ref(const char *name, int len, unsigned int flags)
 	len -= 5;
 
 	/* REF_NORMAL means that we don't want the magic fake tag refs */
-	if ((flags & REF_NORMAL) && check_ref_format(name) < 0)
+	if ((flags & REF_NORMAL) && check_refname_format(name, 0))
 		return 0;
 
 	/* REF_HEADS means that we want regular branch heads */
diff --git a/environment.c b/environment.c
index e96edcfeb..8174b703c 100644
--- a/environment.c
+++ b/environment.c
@@ -106,7 +106,7 @@ static char *expand_namespace(const char *raw_namespace)
 		if (strcmp((*c)->buf, "/") != 0)
 			strbuf_addf(&buf, "refs/namespaces/%s", (*c)->buf);
 	strbuf_list_free(components);
-	if (check_ref_format(buf.buf) != CHECK_REF_FORMAT_OK)
+	if (check_refname_format(buf.buf, 0))
 		die("bad git namespace path \"%s\"", raw_namespace);
 	strbuf_addch(&buf, '/');
 	return strbuf_detach(&buf, NULL);
diff --git a/fast-import.c b/fast-import.c
index 742e7da6b..f9347f55b 100644
--- a/fast-import.c
+++ b/fast-import.c
@@ -722,13 +722,8 @@ static struct branch *new_branch(const char *name)
 
 	if (b)
 		die("Invalid attempt to create duplicate branch: %s", name);
-	switch (check_ref_format(name)) {
-	case 0: break; /* its valid */
-	case CHECK_REF_FORMAT_ONELEVEL:
-		break; /* valid, but too few '/', allow anyway */
-	default:
+	if (check_refname_format(name, REFNAME_ALLOW_ONELEVEL))
 		die("Branch name doesn't conform to GIT standards: %s", name);
-	}
 
 	b = pool_calloc(1, sizeof(struct branch));
 	b->name = pool_strdup(name);
diff --git a/git_remote_helpers/git/git.py b/git_remote_helpers/git/git.py
index a383e6c08..007a1bfdf 100644
--- a/git_remote_helpers/git/git.py
+++ b/git_remote_helpers/git/git.py
@@ -54,7 +54,7 @@ def valid_git_ref (ref_name):
     # The following is a reimplementation of the git check-ref-format
     # command.  The rules were derived from the git check-ref-format(1)
     # manual page.  This code should be replaced by a call to
-    # check_ref_format() in the git library, when such is available.
+    # check_refname_format() in the git library, when such is available.
     if ref_name.endswith('/') or \
        ref_name.startswith('.') or \
        ref_name.count('/.') or \
diff --git a/hex.c b/hex.c
index bb402fbaa..9ebc05063 100644
--- a/hex.c
+++ b/hex.c
@@ -39,7 +39,15 @@ int get_sha1_hex(const char *hex, unsigned char *sha1)
 {
 	int i;
 	for (i = 0; i < 20; i++) {
-		unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
+		unsigned int val;
+		/*
+		 * hex[1]=='\0' is caught when val is checked below,
+		 * but if hex[0] is NUL we have to avoid reading
+		 * past the end of the string:
+		 */
+		if (!hex[0])
+			return -1;
+		val = (hexval(hex[0]) << 4) | hexval(hex[1]);
 		if (val & ~0xff)
 			return -1;
 		*sha1++ = val;
diff --git a/notes-merge.c b/notes-merge.c
index e1aaf43b4..3bbcc9deb 100644
--- a/notes-merge.c
+++ b/notes-merge.c
@@ -570,7 +570,8 @@ int notes_merge(struct notes_merge_options *o,
 	/* Dereference o->local_ref into local_sha1 */
 	if (!resolve_ref(o->local_ref, local_sha1, 0, NULL))
 		die("Failed to resolve local notes ref '%s'", o->local_ref);
-	else if (!check_ref_format(o->local_ref) && is_null_sha1(local_sha1))
+	else if (!check_refname_format(o->local_ref, 0) &&
+		is_null_sha1(local_sha1))
 		local = NULL; /* local_sha1 == null_sha1 indicates unborn ref */
 	else if (!(local = lookup_commit_reference(local_sha1)))
 		die("Could not parse local commit %s (%s)",
@@ -583,7 +584,7 @@ int notes_merge(struct notes_merge_options *o,
 		 * Failed to get remote_sha1. If o->remote_ref looks like an
 		 * unborn ref, perform the merge using an empty notes tree.
 		 */
-		if (!check_ref_format(o->remote_ref)) {
+		if (!check_refname_format(o->remote_ref, 0)) {
 			hashclr(remote_sha1);
 			remote = NULL;
 		} else {
diff --git a/pack-refs.c b/pack-refs.c
index 129057026..23bbd00e3 100644
--- a/pack-refs.c
+++ b/pack-refs.c
@@ -72,7 +72,7 @@ static void try_remove_empty_parents(char *name)
 	for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */
 		while (*p && *p != '/')
 			p++;
-		/* tolerate duplicate slashes; see check_ref_format() */
+		/* tolerate duplicate slashes; see check_refname_format() */
 		while (*p == '/')
 			p++;
 	}
diff --git a/refs.c b/refs.c
index 6e9588bf1..8c69243b2 100644
--- a/refs.c
+++ b/refs.c
@@ -56,6 +56,8 @@ static struct ref_list *add_ref(const char *name, const unsigned char *sha1,
 	entry = xmalloc(sizeof(struct ref_list) + len);
 	hashcpy(entry->sha1, sha1);
 	hashclr(entry->peeled);
+	if (check_refname_format(name, REFNAME_ALLOW_ONELEVEL|REFNAME_DOT_COMPONENT))
+		die("Reference has invalid format: '%s'", name);
 	memcpy(entry->name, name, len);
 	entry->flag = flag;
 	entry->next = list;
@@ -508,29 +510,37 @@ int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *re
 }
 
 /*
- * If the "reading" argument is set, this function finds out what _object_
- * the ref points at by "reading" the ref.  The ref, if it is not symbolic,
- * has to exist, and if it is symbolic, it has to point at an existing ref,
- * because the "read" goes through the symref to the ref it points at.
- *
- * The access that is not "reading" may often be "writing", but does not
- * have to; it can be merely checking _where it leads to_. If it is a
- * prelude to "writing" to the ref, a write to a symref that points at
- * yet-to-be-born ref will create the real ref pointed by the symref.
- * reading=0 allows the caller to check where such a symref leads to.
+ * Try to read ref from the packed references.  On success, set sha1
+ * and return 0; otherwise, return -1.
  */
+static int get_packed_ref(const char *ref, unsigned char *sha1)
+{
+	struct ref_list *list = get_packed_refs(NULL);
+	while (list) {
+		if (!strcmp(ref, list->name)) {
+			hashcpy(sha1, list->sha1);
+			return 0;
+		}
+		list = list->next;
+	}
+	return -1;
+}
+
 const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *flag)
 {
 	int depth = MAXDEPTH;
 	ssize_t len;
 	char buffer[256];
 	static char ref_buffer[256];
+	char path[PATH_MAX];
 
 	if (flag)
 		*flag = 0;
 
+	if (check_refname_format(ref, REFNAME_ALLOW_ONELEVEL))
+		return NULL;
+
 	for (;;) {
-		char path[PATH_MAX];
 		struct stat st;
 		char *buf;
 		int fd;
@@ -539,29 +549,36 @@ const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *
 			return NULL;
 
 		git_snpath(path, sizeof(path), "%s", ref);
-		/* Special case: non-existing file. */
+
 		if (lstat(path, &st) < 0) {
-			struct ref_list *list = get_packed_refs(NULL);
-			while (list) {
-				if (!strcmp(ref, list->name)) {
-					hashcpy(sha1, list->sha1);
-					if (flag)
-						*flag |= REF_ISPACKED;
-					return ref;
-				}
-				list = list->next;
+			if (errno != ENOENT)
+				return NULL;
+			/*
+			 * The loose reference file does not exist;
+			 * check for a packed reference.
+			 */
+			if (!get_packed_ref(ref, sha1)) {
+				if (flag)
+					*flag |= REF_ISPACKED;
+				return ref;
 			}
-			if (reading || errno != ENOENT)
+			/* The reference is not a packed reference, either. */
+			if (reading) {
 				return NULL;
-			hashclr(sha1);
-			return ref;
+			} else {
+				hashclr(sha1);
+				return ref;
+			}
 		}
 
 		/* Follow "normalized" - ie "refs/.." symlinks by hand */
 		if (S_ISLNK(st.st_mode)) {
 			len = readlink(path, buffer, sizeof(buffer)-1);
-			if (len >= 5 && !memcmp("refs/", buffer, 5)) {
-				buffer[len] = 0;
+			if (len < 0)
+				return NULL;
+			buffer[len] = 0;
+			if (!prefixcmp(buffer, "refs/") &&
+					!check_refname_format(buffer, 0)) {
 				strcpy(ref_buffer, buffer);
 				ref = ref_buffer;
 				if (flag)
@@ -585,26 +602,34 @@ const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *
 			return NULL;
 		len = read_in_full(fd, buffer, sizeof(buffer)-1);
 		close(fd);
+		if (len < 0)
+			return NULL;
+		while (len && isspace(buffer[len-1]))
+			len--;
+		buffer[len] = '\0';
 
 		/*
 		 * Is it a symbolic ref?
 		 */
-		if (len < 4 || memcmp("ref:", buffer, 4))
+		if (prefixcmp(buffer, "ref:"))
 			break;
 		buf = buffer + 4;
-		len -= 4;
-		while (len && isspace(*buf))
-			buf++, len--;
-		while (len && isspace(buf[len-1]))
-			len--;
-		buf[len] = 0;
-		memcpy(ref_buffer, buf, len + 1);
-		ref = ref_buffer;
+		while (isspace(*buf))
+			buf++;
+		if (check_refname_format(buf, REFNAME_ALLOW_ONELEVEL)) {
+			warning("symbolic reference in %s is formatted incorrectly",
+				path);
+			return NULL;
+		}
+		ref = strcpy(ref_buffer, buf);
 		if (flag)
 			*flag |= REF_ISSYMREF;
 	}
-	if (len < 40 || get_sha1_hex(buffer, sha1))
+	/* Please note that FETCH_HEAD has a second line containing other data. */
+	if (get_sha1_hex(buffer, sha1) || (buffer[40] != '\0' && !isspace(buffer[40]))) {
+		warning("reference in %s is formatted incorrectly", path);
 		return NULL;
+	}
 	return ref;
 }
 
@@ -902,70 +927,87 @@ int for_each_rawref(each_ref_fn fn, void *cb_data)
  * - it contains a "\" (backslash)
  */
 
+/* Return true iff ch is not allowed in reference names. */
 static inline int bad_ref_char(int ch)
 {
 	if (((unsigned) ch) <= ' ' || ch == 0x7f ||
 	    ch == '~' || ch == '^' || ch == ':' || ch == '\\')
 		return 1;
 	/* 2.13 Pattern Matching Notation */
-	if (ch == '?' || ch == '[') /* Unsupported */
+	if (ch == '*' || ch == '?' || ch == '[') /* Unsupported */
 		return 1;
-	if (ch == '*') /* Supported at the end */
-		return 2;
 	return 0;
 }
 
-int check_ref_format(const char *ref)
+/*
+ * Try to read one refname component from the front of ref.  Return
+ * the length of the component found, or -1 if the component is not
+ * legal.
+ */
+static int check_refname_component(const char *ref, int flags)
 {
-	int ch, level, bad_type, last;
-	int ret = CHECK_REF_FORMAT_OK;
-	const char *cp = ref;
-
-	level = 0;
-	while (1) {
-		while ((ch = *cp++) == '/')
-			; /* tolerate duplicated slashes */
-		if (!ch)
-			/* should not end with slashes */
-			return CHECK_REF_FORMAT_ERROR;
-
-		/* we are at the beginning of the path component */
-		if (ch == '.')
-			return CHECK_REF_FORMAT_ERROR;
-		bad_type = bad_ref_char(ch);
-		if (bad_type) {
-			if (bad_type == 2 && (!*cp || *cp == '/') &&
-			    ret == CHECK_REF_FORMAT_OK)
-				ret = CHECK_REF_FORMAT_WILDCARD;
-			else
-				return CHECK_REF_FORMAT_ERROR;
-		}
+	const char *cp;
+	char last = '\0';
 
+	for (cp = ref; ; cp++) {
+		char ch = *cp;
+		if (ch == '\0' || ch == '/')
+			break;
+		if (bad_ref_char(ch))
+			return -1; /* Illegal character in refname. */
+		if (last == '.' && ch == '.')
+			return -1; /* Refname contains "..". */
+		if (last == '@' && ch == '{')
+			return -1; /* Refname contains "@{". */
 		last = ch;
-		/* scan the rest of the path component */
-		while ((ch = *cp++) != 0) {
-			bad_type = bad_ref_char(ch);
-			if (bad_type)
-				return CHECK_REF_FORMAT_ERROR;
-			if (ch == '/')
-				break;
-			if (last == '.' && ch == '.')
-				return CHECK_REF_FORMAT_ERROR;
-			if (last == '@' && ch == '{')
-				return CHECK_REF_FORMAT_ERROR;
-			last = ch;
-		}
-		level++;
-		if (!ch) {
-			if (ref <= cp - 2 && cp[-2] == '.')
-				return CHECK_REF_FORMAT_ERROR;
-			if (level < 2)
-				return CHECK_REF_FORMAT_ONELEVEL;
-			if (has_extension(ref, ".lock"))
-				return CHECK_REF_FORMAT_ERROR;
-			return ret;
+	}
+	if (cp == ref)
+		return -1; /* Component has zero length. */
+	if (ref[0] == '.') {
+		if (!(flags & REFNAME_DOT_COMPONENT))
+			return -1; /* Component starts with '.'. */
+		/*
+		 * Even if leading dots are allowed, don't allow "."
+		 * as a component (".." is prevented by a rule above).
+		 */
+		if (ref[1] == '\0')
+			return -1; /* Component equals ".". */
+	}
+	if (cp - ref >= 5 && !memcmp(cp - 5, ".lock", 5))
+		return -1; /* Refname ends with ".lock". */
+	return cp - ref;
+}
+
+int check_refname_format(const char *ref, int flags)
+{
+	int component_len, component_count = 0;
+
+	while (1) {
+		/* We are at the start of a path component. */
+		component_len = check_refname_component(ref, flags);
+		if (component_len < 0) {
+			if ((flags & REFNAME_REFSPEC_PATTERN) &&
+					ref[0] == '*' &&
+					(ref[1] == '\0' || ref[1] == '/')) {
+				/* Accept one wildcard as a full refname component. */
+				flags &= ~REFNAME_REFSPEC_PATTERN;
+				component_len = 1;
+			} else {
+				return -1;
+			}
 		}
+		component_count++;
+		if (ref[component_len] == '\0')
+			break;
+		/* Skip to next component. */
+		ref += component_len + 1;
 	}
+
+	if (ref[component_len - 1] == '.')
+		return -1; /* Refname ends with '.'. */
+	if (!(flags & REFNAME_ALLOW_ONELEVEL) && component_count < 2)
+		return -1; /* Refname has only one component. */
+	return 0;
 }
 
 const char *prettify_refname(const char *name)
@@ -1148,7 +1190,7 @@ static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char
 struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
 {
 	char refpath[PATH_MAX];
-	if (check_ref_format(ref))
+	if (check_refname_format(ref, 0))
 		return NULL;
 	strcpy(refpath, mkpath("refs/%s", ref));
 	return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
@@ -1156,13 +1198,9 @@ struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
 
 struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1, int flags)
 {
-	switch (check_ref_format(ref)) {
-	default:
+	if (check_refname_format(ref, REFNAME_ALLOW_ONELEVEL))
 		return NULL;
-	case 0:
-	case CHECK_REF_FORMAT_ONELEVEL:
-		return lock_ref_sha1_basic(ref, old_sha1, flags, NULL);
-	}
+	return lock_ref_sha1_basic(ref, old_sha1, flags, NULL);
 }
 
 static struct lock_file packlock;
diff --git a/refs.h b/refs.h
index dfb086e93..d5ac13333 100644
--- a/refs.h
+++ b/refs.h
@@ -97,11 +97,22 @@ int for_each_recent_reflog_ent(const char *ref, each_reflog_ent_fn fn, long, voi
  */
 extern int for_each_reflog(each_ref_fn, void *);
 
-#define CHECK_REF_FORMAT_OK 0
-#define CHECK_REF_FORMAT_ERROR (-1)
-#define CHECK_REF_FORMAT_ONELEVEL (-2)
-#define CHECK_REF_FORMAT_WILDCARD (-3)
-extern int check_ref_format(const char *target);
+#define REFNAME_ALLOW_ONELEVEL 1
+#define REFNAME_REFSPEC_PATTERN 2
+#define REFNAME_DOT_COMPONENT 4
+
+/*
+ * Return 0 iff ref has the correct format for a refname according to
+ * the rules described in Documentation/git-check-ref-format.txt.  If
+ * REFNAME_ALLOW_ONELEVEL is set in flags, then accept one-level
+ * reference names.  If REFNAME_REFSPEC_PATTERN is set in flags, then
+ * allow a "*" wildcard character in place of one of the name
+ * components.  No leading or repeated slashes are accepted.  If
+ * REFNAME_DOT_COMPONENT is set in flags, then allow refname
+ * components to start with "." (but not a whole component equal to
+ * "." or "..").
+ */
+extern int check_refname_format(const char *ref, int flags);
 
 extern const char *prettify_refname(const char *refname);
 extern char *shorten_unambiguous_ref(const char *ref, int strict);
diff --git a/remote.c b/remote.c
index b8ecfa5d9..e52aa9b25 100644
--- a/remote.c
+++ b/remote.c
@@ -493,23 +493,6 @@ static void read_config(void)
 }
 
 /*
- * We need to make sure the remote-tracking branches are well formed, but a
- * wildcard refspec in "struct refspec" must have a trailing slash. We
- * temporarily drop the trailing '/' while calling check_ref_format(),
- * and put it back.  The caller knows that a CHECK_REF_FORMAT_ONELEVEL
- * error return is Ok for a wildcard refspec.
- */
-static int verify_refname(char *name, int is_glob)
-{
-	int result;
-
-	result = check_ref_format(name);
-	if (is_glob && result == CHECK_REF_FORMAT_WILDCARD)
-		result = CHECK_REF_FORMAT_OK;
-	return result;
-}
-
-/*
  * This function frees a refspec array.
  * Warning: code paths should be checked to ensure that the src
  *          and dst pointers are always freeable pointers as well
@@ -532,13 +515,13 @@ static void free_refspecs(struct refspec *refspec, int nr_refspec)
 static struct refspec *parse_refspec_internal(int nr_refspec, const char **refspec, int fetch, int verify)
 {
 	int i;
-	int st;
 	struct refspec *rs = xcalloc(sizeof(*rs), nr_refspec);
 
 	for (i = 0; i < nr_refspec; i++) {
 		size_t llen;
 		int is_glob;
 		const char *lhs, *rhs;
+		int flags;
 
 		is_glob = 0;
 
@@ -576,6 +559,7 @@ static struct refspec *parse_refspec_internal(int nr_refspec, const char **refsp
 
 		rs[i].pattern = is_glob;
 		rs[i].src = xstrndup(lhs, llen);
+		flags = REFNAME_ALLOW_ONELEVEL | (is_glob ? REFNAME_REFSPEC_PATTERN : 0);
 
 		if (fetch) {
 			/*
@@ -585,26 +569,20 @@ static struct refspec *parse_refspec_internal(int nr_refspec, const char **refsp
 			 */
 			if (!*rs[i].src)
 				; /* empty is ok */
-			else {
-				st = verify_refname(rs[i].src, is_glob);
-				if (st && st != CHECK_REF_FORMAT_ONELEVEL)
-					goto invalid;
-			}
+			else if (check_refname_format(rs[i].src, flags))
+				goto invalid;
 			/*
 			 * RHS
 			 * - missing is ok, and is same as empty.
 			 * - empty is ok; it means not to store.
 			 * - otherwise it must be a valid looking ref.
 			 */
-			if (!rs[i].dst) {
+			if (!rs[i].dst)
 				; /* ok */
-			} else if (!*rs[i].dst) {
+			else if (!*rs[i].dst)
 				; /* ok */
-			} else {
-				st = verify_refname(rs[i].dst, is_glob);
-				if (st && st != CHECK_REF_FORMAT_ONELEVEL)
-					goto invalid;
-			}
+			else if (check_refname_format(rs[i].dst, flags))
+				goto invalid;
 		} else {
 			/*
 			 * LHS
@@ -616,8 +594,7 @@ static struct refspec *parse_refspec_internal(int nr_refspec, const char **refsp
 			if (!*rs[i].src)
 				; /* empty is ok */
 			else if (is_glob) {
-				st = verify_refname(rs[i].src, is_glob);
-				if (st && st != CHECK_REF_FORMAT_ONELEVEL)
+				if (check_refname_format(rs[i].src, flags))
 					goto invalid;
 			}
 			else
@@ -630,14 +607,12 @@ static struct refspec *parse_refspec_internal(int nr_refspec, const char **refsp
 			 * - otherwise it must be a valid looking ref.
 			 */
 			if (!rs[i].dst) {
-				st = verify_refname(rs[i].src, is_glob);
-				if (st && st != CHECK_REF_FORMAT_ONELEVEL)
+				if (check_refname_format(rs[i].src, flags))
 					goto invalid;
 			} else if (!*rs[i].dst) {
 				goto invalid;
 			} else {
-				st = verify_refname(rs[i].dst, is_glob);
-				if (st && st != CHECK_REF_FORMAT_ONELEVEL)
+				if (check_refname_format(rs[i].dst, flags))
 					goto invalid;
 			}
 		}
@@ -840,7 +815,7 @@ char *apply_refspecs(struct refspec *refspecs, int nr_refspec,
 						    refspec->dst, &ret))
 				return ret;
 		} else if (!strcmp(refspec->src, name))
-			return strdup(refspec->dst);
+			return xstrdup(refspec->dst);
 	}
 	return NULL;
 }
@@ -1427,8 +1402,8 @@ int get_fetch_map(const struct ref *remote_refs,
 
 	for (rmp = &ref_map; *rmp; ) {
 		if ((*rmp)->peer_ref) {
-			int st = check_ref_format((*rmp)->peer_ref->name + 5);
-			if (st && st != CHECK_REF_FORMAT_ONELEVEL) {
+			if (check_refname_format((*rmp)->peer_ref->name + 5,
+				REFNAME_ALLOW_ONELEVEL)) {
 				struct ref *ignore = *rmp;
 				error("* Ignoring funny ref '%s' locally",
 				      (*rmp)->peer_ref->name);
@@ -1620,7 +1595,7 @@ static int one_local_ref(const char *refname, const unsigned char *sha1, int fla
 	int len;
 
 	/* we already know it starts with refs/ to get here */
-	if (check_ref_format(refname + 5))
+	if (check_refname_format(refname + 5, 0))
 		return 0;
 
 	len = strlen(refname) + 1;
diff --git a/sha1_name.c b/sha1_name.c
index 653b0659b..ba976b483 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -966,9 +966,9 @@ int strbuf_check_branch_ref(struct strbuf *sb, const char *name)
 {
 	strbuf_branchname(sb, name);
 	if (name[0] == '-')
-		return CHECK_REF_FORMAT_ERROR;
+		return -1;
 	strbuf_splice(sb, 0, 0, "refs/heads/", 11);
-	return check_ref_format(sb->buf);
+	return check_refname_format(sb->buf, 0);
 }
 
 /*
diff --git a/t/t1402-check-ref-format.sh b/t/t1402-check-ref-format.sh
index ed4275afe..710fccad3 100755
--- a/t/t1402-check-ref-format.sh
+++ b/t/t1402-check-ref-format.sh
@@ -5,34 +5,124 @@ test_description='Test git check-ref-format'
 . ./test-lib.sh
 
 valid_ref() {
-	test_expect_success "ref name '$1' is valid" \
-		"git check-ref-format '$1'"
+	if test "$#" = 1
+	then
+		test_expect_success "ref name '$1' is valid" \
+			"git check-ref-format '$1'"
+	else
+		test_expect_success "ref name '$1' is valid with options $2" \
+			"git check-ref-format $2 '$1'"
+	fi
 }
 invalid_ref() {
-	test_expect_success "ref name '$1' is not valid" \
-		"test_must_fail git check-ref-format '$1'"
+	if test "$#" = 1
+	then
+		test_expect_success "ref name '$1' is invalid" \
+			"test_must_fail git check-ref-format '$1'"
+	else
+		test_expect_success "ref name '$1' is invalid with options $2" \
+			"test_must_fail git check-ref-format $2 '$1'"
+	fi
 }
 
-valid_ref 'heads/foo'
-invalid_ref 'foo'
+invalid_ref ''
+invalid_ref '/'
+invalid_ref '/' --allow-onelevel
+invalid_ref '/' --normalize
+invalid_ref '/' '--allow-onelevel --normalize'
 valid_ref 'foo/bar/baz'
-valid_ref 'refs///heads/foo'
+valid_ref 'foo/bar/baz' --normalize
+invalid_ref 'refs///heads/foo'
+valid_ref 'refs///heads/foo' --normalize
 invalid_ref 'heads/foo/'
-valid_ref '/heads/foo'
-valid_ref '///heads/foo'
-invalid_ref '/foo'
+invalid_ref '/heads/foo'
+valid_ref '/heads/foo' --normalize
+invalid_ref '///heads/foo'
+valid_ref '///heads/foo' --normalize
 invalid_ref './foo'
+invalid_ref './foo/bar'
+invalid_ref 'foo/./bar'
+invalid_ref 'foo/bar/.'
 invalid_ref '.refs/foo'
 invalid_ref 'heads/foo..bar'
 invalid_ref 'heads/foo?bar'
 valid_ref 'foo./bar'
 invalid_ref 'heads/foo.lock'
+invalid_ref 'heads///foo.lock'
+invalid_ref 'foo.lock/bar'
+invalid_ref 'foo.lock///bar'
 valid_ref 'heads/foo@bar'
 invalid_ref 'heads/v@{ation'
 invalid_ref 'heads/foo\bar'
 invalid_ref "$(printf 'heads/foo\t')"
 invalid_ref "$(printf 'heads/foo\177')"
 valid_ref "$(printf 'heads/fu\303\237')"
+invalid_ref 'heads/*foo/bar' --refspec-pattern
+invalid_ref 'heads/foo*/bar' --refspec-pattern
+invalid_ref 'heads/f*o/bar' --refspec-pattern
+
+ref='foo'
+invalid_ref "$ref"
+valid_ref "$ref" --allow-onelevel
+invalid_ref "$ref" --refspec-pattern
+valid_ref "$ref" '--refspec-pattern --allow-onelevel'
+invalid_ref "$ref" --normalize
+valid_ref "$ref" '--allow-onelevel --normalize'
+
+ref='foo/bar'
+valid_ref "$ref"
+valid_ref "$ref" --allow-onelevel
+valid_ref "$ref" --refspec-pattern
+valid_ref "$ref" '--refspec-pattern --allow-onelevel'
+valid_ref "$ref" --normalize
+
+ref='foo/*'
+invalid_ref "$ref"
+invalid_ref "$ref" --allow-onelevel
+valid_ref "$ref" --refspec-pattern
+valid_ref "$ref" '--refspec-pattern --allow-onelevel'
+
+ref='*/foo'
+invalid_ref "$ref"
+invalid_ref "$ref" --allow-onelevel
+valid_ref "$ref" --refspec-pattern
+valid_ref "$ref" '--refspec-pattern --allow-onelevel'
+invalid_ref "$ref" --normalize
+valid_ref "$ref" '--refspec-pattern --normalize'
+
+ref='foo/*/bar'
+invalid_ref "$ref"
+invalid_ref "$ref" --allow-onelevel
+valid_ref "$ref" --refspec-pattern
+valid_ref "$ref" '--refspec-pattern --allow-onelevel'
+
+ref='*'
+invalid_ref "$ref"
+invalid_ref "$ref" --allow-onelevel
+invalid_ref "$ref" --refspec-pattern
+valid_ref "$ref" '--refspec-pattern --allow-onelevel'
+
+ref='foo/*/*'
+invalid_ref "$ref" --refspec-pattern
+invalid_ref "$ref" '--refspec-pattern --allow-onelevel'
+
+ref='*/foo/*'
+invalid_ref "$ref" --refspec-pattern
+invalid_ref "$ref" '--refspec-pattern --allow-onelevel'
+
+ref='*/*/foo'
+invalid_ref "$ref" --refspec-pattern
+invalid_ref "$ref" '--refspec-pattern --allow-onelevel'
+
+ref='/foo'
+invalid_ref "$ref"
+invalid_ref "$ref" --allow-onelevel
+invalid_ref "$ref" --refspec-pattern
+invalid_ref "$ref" '--refspec-pattern --allow-onelevel'
+invalid_ref "$ref" --normalize
+valid_ref "$ref" '--allow-onelevel --normalize'
+invalid_ref "$ref" '--refspec-pattern --normalize'
+valid_ref "$ref" '--refspec-pattern --allow-onelevel --normalize'
 
 test_expect_success "check-ref-format --branch @{-1}" '
 	T=$(git write-tree) &&
@@ -66,12 +156,12 @@ test_expect_success 'check-ref-format --branch from subdir' '
 
 valid_ref_normalized() {
 	test_expect_success "ref name '$1' simplifies to '$2'" "
-		refname=\$(git check-ref-format --print '$1') &&
+		refname=\$(git check-ref-format --normalize '$1') &&
 		test \"\$refname\" = '$2'"
 }
 invalid_ref_normalized() {
-	test_expect_success "check-ref-format --print rejects '$1'" "
-		test_must_fail git check-ref-format --print '$1'"
+	test_expect_success "check-ref-format --normalize rejects '$1'" "
+		test_must_fail git check-ref-format --normalize '$1'"
 }
 
 valid_ref_normalized 'heads/foo' 'heads/foo'
@@ -83,5 +173,9 @@ invalid_ref_normalized '/foo'
 invalid_ref_normalized 'heads/foo/../bar'
 invalid_ref_normalized 'heads/./foo'
 invalid_ref_normalized 'heads\foo'
+invalid_ref_normalized 'heads/foo.lock'
+invalid_ref_normalized 'heads///foo.lock'
+invalid_ref_normalized 'foo.lock/bar'
+invalid_ref_normalized 'foo.lock///bar'
 
 test_done
diff --git a/transport-helper.c b/transport-helper.c
index 4eab844d4..6f227e253 100644
--- a/transport-helper.c
+++ b/transport-helper.c
@@ -183,7 +183,7 @@ static struct child_process *get_helper(struct transport *transport)
 			ALLOC_GROW(refspecs,
 				   refspec_nr + 1,
 				   refspec_alloc);
-			refspecs[refspec_nr++] = strdup(capname + strlen("refspec "));
+			refspecs[refspec_nr++] = xstrdup(capname + strlen("refspec "));
 		} else if (!strcmp(capname, "connect")) {
 			data->connect = 1;
 		} else if (!prefixcmp(capname, "export-marks ")) {
@@ -445,9 +445,11 @@ static int fetch_with_import(struct transport *transport,
 		if (data->refspecs)
 			private = apply_refspecs(data->refspecs, data->refspec_nr, posn->name);
 		else
-			private = strdup(posn->name);
-		read_ref(private, posn->old_sha1);
-		free(private);
+			private = xstrdup(posn->name);
+		if (private) {
+			read_ref(private, posn->old_sha1);
+			free(private);
+		}
 	}
 	strbuf_release(&buf);
 	return 0;
diff --git a/transport.c b/transport.c
index e1940615e..c048ef179 100644
--- a/transport.c
+++ b/transport.c
@@ -755,18 +755,10 @@ void transport_verify_remote_names(int nr_heads, const char **heads)
 			continue;
 
 		remote = remote ? (remote + 1) : local;
-		switch (check_ref_format(remote)) {
-		case 0: /* ok */
-		case CHECK_REF_FORMAT_ONELEVEL:
-			/* ok but a single level -- that is fine for
-			 * a match pattern.
-			 */
-		case CHECK_REF_FORMAT_WILDCARD:
-			/* ok but ends with a pattern-match character */
-			continue;
-		}
-		die("remote part of refspec is not a valid name in %s",
-		    heads[i]);
+		if (check_refname_format(remote,
+				REFNAME_ALLOW_ONELEVEL|REFNAME_REFSPEC_PATTERN))
+			die("remote part of refspec is not a valid name in %s",
+				heads[i]);
 	}
 }
 
diff --git a/walker.c b/walker.c
index dce7128da..be389dc9b 100644
--- a/walker.c
+++ b/walker.c
@@ -190,7 +190,7 @@ static int interpret_target(struct walker *walker, char *target, unsigned char *
 {
 	if (!get_sha1_hex(target, sha1))
 		return 0;
-	if (!check_ref_format(target)) {
+	if (!check_refname_format(target, 0)) {
 		struct ref *ref = alloc_ref(target);
 		if (!walker->fetch_ref(walker, ref)) {
 			hashcpy(sha1, ref->old_sha1);