thodg/libgit2

diff --git a/include/git2/refs.h b/include/git2/refs.h
index 73b32a9..10b73f0 100644
--- a/include/git2/refs.h
+++ b/include/git2/refs.h
@@ -392,7 +392,8 @@ enum {
 	/**
 	 * Control whether one-level refnames are accepted
 	 * (i.e., refnames that do not contain multiple /-separated
-	 * components)
+	 * components). Those are expected to be written only using
+	 * uppercase letters and underscore (FETCH_HEAD, ...)
 	 */
 	GIT_REF_FORMAT_ALLOW_ONELEVEL = (1 << 0),
 
@@ -414,8 +415,6 @@ enum {
  * Once normalized, if the reference name is valid, it will be
  * returned in the user allocated buffer.
  *
- * TODO: Implement handling of GIT_REF_FORMAT_REFSPEC_PATTERN
- *
  * @param buffer_out The user allocated buffer where the
  * normalized name will be stored.
  *
@@ -454,6 +453,16 @@ GIT_EXTERN(int) git_reference_peel(
 	git_reference *ref,
 	git_otype type);
 
+/**
+ * Ensure the reference name is well-formed.
+ *
+ * @param refname name to be checked.
+ *
+ * @return 1 if the reference name is acceptable; 0 if it isn't
+ */
+GIT_EXTERN(int) git_reference_is_valid_name(
+	const char *refname);
+
 /** @} */
 GIT_END_DECL
 #endif
diff --git a/src/refs.c b/src/refs.c
index 74c40e8..693870a 100644
--- a/src/refs.c
+++ b/src/refs.c
@@ -1098,7 +1098,7 @@ int git_reference_lookup_resolved(
 	scan->name = git__calloc(GIT_REFNAME_MAX + 1, sizeof(char));
 	GITERR_CHECK_ALLOC(scan->name);
 
-	if ((result = git_reference__normalize_name(
+	if ((result = git_reference__normalize_name_lax(
 		scan->name,
 		GIT_REFNAME_MAX,
 		name)) < 0) {
@@ -1200,7 +1200,7 @@ int git_reference_create_symbolic(
 	char normalized[GIT_REFNAME_MAX];
 	git_reference *ref = NULL;
 
-	if (git_reference__normalize_name(
+	if (git_reference__normalize_name_lax(
 		normalized,
 		sizeof(normalized),
 		name) < 0)
@@ -1239,7 +1239,7 @@ int git_reference_create_oid(
 	git_reference *ref = NULL;
 	char normalized[GIT_REFNAME_MAX];
 
-	if (git_reference__normalize_name_oid(
+	if (git_reference__normalize_name_lax(
 		normalized,
 		sizeof(normalized),
 		name) < 0)
@@ -1322,7 +1322,7 @@ int git_reference_set_target(git_reference *ref, const char *target)
 		return -1;
 	}
 
-	if (git_reference__normalize_name(
+	if (git_reference__normalize_name_lax(
 		normalized,
 		sizeof(normalized),
 		target))
@@ -1584,118 +1584,175 @@ static int is_valid_ref_char(char ch)
 	}
 }
 
-int git_reference_normalize_name(
-	char *buffer_out,
-	size_t buffer_size,
-	const char *name,
-	unsigned int flags)
+static int ensure_segment_validity(const char *name)
 {
-	const char *name_end, *buffer_out_start;
-	const char *current;
-	int contains_a_slash = 0;
+	const char *current = name;
+	char prev = '\0';
 
-	assert(name && buffer_out);
+	if (*current == '.')
+		return -1; /* Refname starts with "." */
 
-	if (flags & GIT_REF_FORMAT_REFSPEC_PATTERN) {
-		giterr_set(GITERR_INVALID, "Unimplemented");
-		return -1;
-	}
+	for (current = name; ; current++) {
+		if (*current == '\0' || *current == '/')
+			break;
 
-	buffer_out_start = buffer_out;
-	current = name;
-	name_end = name + strlen(name);
+		if (!is_valid_ref_char(*current))
+			return -1; /* Illegal character in refname */
 
-	/* Terminating null byte */
-	buffer_size--;
+		if (prev == '.' && *current == '.')
+			return -1; /* Refname contains ".." */
 
-	/* A refname can not be empty */
-	if (name_end == name)
-		goto invalid_name;
+		if (prev == '@' && *current == '{')
+			return -1; /* Refname contains "@{" */
 
-	/* A refname can not end with a dot or a slash */
-	if (*(name_end - 1) == '.' || *(name_end - 1) == '/')
-		goto invalid_name;
+		prev = *current;
+	}
 
-	while (current < name_end && buffer_size > 0) {
-		if (!is_valid_ref_char(*current))
-			goto invalid_name;
+	return current - name;
+}
 
-		if (buffer_out > buffer_out_start) {
-			char prev = *(buffer_out - 1);
+static bool is_all_caps_and_underscore(const char *name, int len)
+{
+	int i;
+	char c;
+
+	assert(name && len > 0);
 
-			/* A refname can not start with a dot nor contain a double dot */
-			if (*current == '.' && ((prev == '.') || (prev == '/')))
-				goto invalid_name;
+	for (i = 0; i < len; i++)
+	{
+		c = name[i];
+		if ((c < 'A' || c > 'Z') && c != '_')
+			return false;
+	}
 
-			/* '@{' is forbidden within a refname */
-			if (*current == '{' && prev == '@')
-				goto invalid_name;
+	if (*name == '_' || name[len - 1] == '_')
+		return false;
 
-			/* Prevent multiple slashes from being added to the output */
-			if (*current == '/' && prev == '/') {
-				current++;
-				continue;
-			}
+	return true;
+}
+
+int git_reference__normalize_name(
+	git_buf *buf,
+	const char *name,
+	unsigned int flags)
+{
+	// Inspired from https://github.com/git/git/blob/f06d47e7e0d9db709ee204ed13a8a7486149f494/refs.c#L36-100
+
+	char *current;
+	int segment_len, segments_count = 0, error = -1;
+	unsigned int process_flags;
+	bool normalize = (buf != NULL);
+	assert(name);
+
+	process_flags = flags;
+	current = (char *)name;
+
+	if (normalize)
+		git_buf_clear(buf);
+
+	while (true) {
+		segment_len = ensure_segment_validity(current);
+		if (segment_len < 0) {
+			if ((process_flags & GIT_REF_FORMAT_REFSPEC_PATTERN) &&
+					current[0] == '*' &&
+					(current[1] == '\0' || current[1] == '/')) {
+				/* Accept one wildcard as a full refname component. */
+				process_flags &= ~GIT_REF_FORMAT_REFSPEC_PATTERN;
+				segment_len = 1;
+			} else
+				goto cleanup;
 		}
 
-		if (*current == '/') {
-			if (buffer_out > buffer_out_start)
-				contains_a_slash = 1;
-			else {
-				current++;
-				continue;
+		if (segment_len > 0) {
+			if (normalize) {
+				int cur_len = git_buf_len(buf);
+
+				git_buf_joinpath(buf, git_buf_cstr(buf), current);
+				git_buf_truncate(buf, 
+					cur_len + segment_len + (segments_count ? 1 : 0));
+
+				if (git_buf_oom(buf))
+					goto cleanup;
 			}
+
+			segments_count++;
 		}
 
-		*buffer_out++ = *current++;
-		buffer_size--;
-	}
+		if (current[segment_len] == '\0')
+			break;
 
-	if (current < name_end) {
-		giterr_set(
-		GITERR_REFERENCE,
-		"The provided buffer is too short to hold the normalization of '%s'", name);
-		return GIT_EBUFS;
+		current += segment_len + 1;
 	}
 
-	/* Object id refname have to contain at least one slash, except
-	 * for HEAD in a detached state or MERGE_HEAD if we're in the
-	 * middle of a merge */
-	if (!(flags & GIT_REF_FORMAT_ALLOW_ONELEVEL) &&
-		!contains_a_slash &&
-		strcmp(name, GIT_HEAD_FILE) != 0 &&
-		strcmp(name, GIT_MERGE_HEAD_FILE) != 0 &&
-		strcmp(name, GIT_FETCH_HEAD_FILE) != 0)
-		goto invalid_name;
+	/* A refname can not be empty */
+	if (segment_len == 0 && segments_count == 0)
+		goto cleanup;
+
+	/* A refname can not end with "." */
+	if (current[segment_len - 1] == '.')
+		goto cleanup;
+
+	/* A refname can not end with "/" */
+	if (current[segment_len - 1] == '/')
+		goto cleanup;
 
 	/* A refname can not end with ".lock" */
 	if (!git__suffixcmp(name, GIT_FILELOCK_EXTENSION))
-		goto invalid_name;
+		goto cleanup;
 
-	*buffer_out = '\0';
+	if ((segments_count == 1 ) && !(flags & GIT_REF_FORMAT_ALLOW_ONELEVEL))
+		goto cleanup;
 
-	return 0;
+	if ((segments_count == 1 ) &&
+		!(is_all_caps_and_underscore(name, segment_len) ||
+			((flags & GIT_REF_FORMAT_REFSPEC_PATTERN) && !strcmp("*", name))))
+			goto cleanup;
 
-invalid_name:
-	giterr_set(
-		GITERR_REFERENCE,
-		"The given reference name '%s' is not valid", name);
-	return -1;
+	if ((segments_count > 1)
+		&& (is_all_caps_and_underscore(name, strchr(name, '/') - name)))
+			goto cleanup;
+
+	error = 0;
+
+cleanup:
+	if (error)
+		giterr_set(
+			GITERR_REFERENCE,
+			"The given reference name '%s' is not valid", name);
+
+	return error;
 }
 
-int git_reference__normalize_name(
+int git_reference_normalize_name(
 	char *buffer_out,
-	size_t out_size,
-	const char *name)
+	size_t buffer_size,
+	const char *name,
+	unsigned int flags)
 {
-	return git_reference_normalize_name(
-		buffer_out,
-		out_size,
-		name,
-		GIT_REF_FORMAT_ALLOW_ONELEVEL);
+	git_buf buf = GIT_BUF_INIT;
+	int error;
+
+	if ((error = git_reference__normalize_name(&buf, name, flags)) < 0)
+		goto cleanup;
+
+	if (git_buf_len(&buf) > buffer_size - 1) {
+		giterr_set(
+		GITERR_REFERENCE,
+		"The provided buffer is too short to hold the normalization of '%s'", name);
+		error = GIT_EBUFS;
+		goto cleanup;
+	}
+
+	git_buf_copy_cstr(buffer_out, buffer_size, &buf);
+
+	error = 0;
+
+cleanup:
+	git_buf_free(&buf);
+	return error;
 }
 
-int git_reference__normalize_name_oid(
+int git_reference__normalize_name_lax(
 	char *buffer_out,
 	size_t out_size,
 	const char *name)
@@ -1704,9 +1761,8 @@ int git_reference__normalize_name_oid(
 		buffer_out,
 		out_size,
 		name,
-		GIT_REF_FORMAT_NORMAL);
+		GIT_REF_FORMAT_ALLOW_ONELEVEL);
 }
-
 #define GIT_REF_TYPEMASK (GIT_REF_OID | GIT_REF_SYMBOLIC)
 
 int git_reference_cmp(git_reference *ref1, git_reference *ref2)
@@ -1895,3 +1951,19 @@ cleanup:
 	git_reference_free(resolved);
 	return error;
 }
+
+int git_reference__is_valid_name(
+	const char *refname,
+	unsigned int flags)
+{
+	giterr_clear();
+	return git_reference__normalize_name(NULL, refname, flags) == 0;
+}
+
+int git_reference_is_valid_name(
+	const char *refname)
+{
+	return git_reference__is_valid_name(
+		refname,
+		GIT_REF_FORMAT_ALLOW_ONELEVEL);
+}
diff --git a/src/refs.h b/src/refs.h
index 0823502..54359f0 100644
--- a/src/refs.h
+++ b/src/refs.h
@@ -11,6 +11,7 @@
 #include "git2/oid.h"
 #include "git2/refs.h"
 #include "strmap.h"
+#include "buffer.h"
 
 #define GIT_REFS_DIR "refs/"
 #define GIT_REFS_HEADS_DIR GIT_REFS_DIR "heads/"
@@ -52,8 +53,9 @@ typedef struct {
 
 void git_repository__refcache_free(git_refcache *refs);
 
-int git_reference__normalize_name(char *buffer_out, size_t out_size, const char *name);
-int git_reference__normalize_name_oid(char *buffer_out, size_t out_size, const char *name);
+int git_reference__normalize_name_lax(char *buffer_out, size_t out_size, const char *name);
+int git_reference__normalize_name(git_buf *buf, const char *name, unsigned int flags);
+int git_reference__is_valid_name(const char *refname, unsigned int flags);
 int git_reference__update(git_repository *repo, const git_oid *oid, const char *ref_name);
 
 /**
diff --git a/src/refspec.c b/src/refspec.c
index b6b1158..1265c56 100644
--- a/src/refspec.c
+++ b/src/refspec.c
@@ -11,6 +11,119 @@
 #include "refspec.h"
 #include "util.h"
 #include "posix.h"
+#include "refs.h"
+
+int git_refspec__parse(git_refspec *refspec, const char *input, bool is_fetch)
+{
+	// Ported from https://github.com/git/git/blob/f06d47e7e0d9db709ee204ed13a8a7486149f494/remote.c#L518-636
+
+	size_t llen;
+	int is_glob = 0;
+	const char *lhs, *rhs;
+	int flags;
+
+	assert(refspec && input);
+
+	memset(refspec, 0x0, sizeof(git_refspec));
+
+	lhs = input;
+	if (*lhs == '+') {
+		refspec->force = 1;
+		lhs++;
+	}
+
+	rhs = strrchr(lhs, ':');
+
+	/*
+	 * Before going on, special case ":" (or "+:") as a refspec
+	 * for matching refs.
+	 */
+	if (!is_fetch && rhs == lhs && rhs[1] == '\0') {
+		refspec->matching = 1;
+		return 0;
+	}
+
+	if (rhs) {
+		size_t rlen = strlen(++rhs);
+		is_glob = (1 <= rlen && strchr(rhs, '*'));
+		refspec->dst = git__strndup(rhs, rlen);
+	}
+
+	llen = (rhs ? (size_t)(rhs - lhs - 1) : strlen(lhs));
+	if (1 <= llen && memchr(lhs, '*', llen)) {
+		if ((rhs && !is_glob) || (!rhs && is_fetch))
+			goto invalid;
+		is_glob = 1;
+	} else if (rhs && is_glob)
+		goto invalid;
+
+	refspec->pattern = is_glob;
+	refspec->src = git__strndup(lhs, llen);
+	flags = GIT_REF_FORMAT_ALLOW_ONELEVEL
+		| (is_glob ? GIT_REF_FORMAT_REFSPEC_PATTERN : 0);
+
+	if (is_fetch) {
+		/*
+			* LHS
+			* - empty is allowed; it means HEAD.
+			* - otherwise it must be a valid looking ref.
+			*/
+		if (!*refspec->src)
+			; /* empty is ok */
+		else if (!git_reference__is_valid_name(refspec->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 (!refspec->dst)
+			; /* ok */
+		else if (!*refspec->dst)
+			; /* ok */
+		else if (!git_reference__is_valid_name(refspec->dst, flags))
+			goto invalid;
+	} else {
+		/*
+			* LHS
+			* - empty is allowed; it means delete.
+			* - when wildcarded, it must be a valid looking ref.
+			* - otherwise, it must be an extended SHA-1, but
+			*   there is no existing way to validate this.
+			*/
+		if (!*refspec->src)
+			; /* empty is ok */
+		else if (is_glob) {
+			if (!git_reference__is_valid_name(refspec->src, flags))
+				goto invalid;
+		}
+		else {
+			; /* anything goes, for now */
+		}
+		/*
+			* RHS
+			* - missing is allowed, but LHS then must be a
+			*   valid looking ref.
+			* - empty is not allowed.
+			* - otherwise it must be a valid looking ref.
+			*/
+		if (!refspec->dst) {
+			if (!git_reference__is_valid_name(refspec->src, flags))
+				goto invalid;
+		} else if (!*refspec->dst) {
+			goto invalid;
+		} else {
+			if (!git_reference__is_valid_name(refspec->dst, flags))
+				goto invalid;
+		}
+	}
+
+	return 0;
+
+ invalid:
+	return -1;
+}
 
 int git_refspec_parse(git_refspec *refspec, const char *str)
 {
diff --git a/src/refspec.h b/src/refspec.h
index 2db5049..2f46b3e 100644
--- a/src/refspec.h
+++ b/src/refspec.h
@@ -20,6 +20,10 @@ struct git_refspec {
 };
 
 int git_refspec_parse(struct git_refspec *refspec, const char *str);
+int git_refspec__parse(
+	struct git_refspec *refspec,
+	const char *str,
+	bool is_fetch);
 
 /**
  * Transform a reference to its target following the refspec's rules,
diff --git a/src/revparse.c b/src/revparse.c
index 17266b9..5e2db99 100644
--- a/src/revparse.c
+++ b/src/revparse.c
@@ -50,6 +50,11 @@ static int disambiguate_refname(git_reference **out, git_repository *repo, const
 		if ((error = git_buf_printf(&refnamebuf, formatters[i], git_buf_cstr(&name))) < 0)
 			goto cleanup;
 
+		if (!git_reference_is_valid_name(git_buf_cstr(&refnamebuf))) {
+			error = GIT_ENOTFOUND;
+			continue;
+		}
+
 		error = git_reference_lookup_resolved(&ref, repo, git_buf_cstr(&refnamebuf), -1);
 
 		if (!error) {
diff --git a/tests-clar/network/refspecs.c b/tests-clar/network/refspecs.c
new file mode 100644
index 0000000..bfe0af4
--- /dev/null
+++ b/tests-clar/network/refspecs.c
@@ -0,0 +1,83 @@
+#include "clar_libgit2.h"
+#include "refspec.h"
+#include "remote.h"
+
+static void assert_refspec(unsigned int direction, const char *input, bool is_expected_to_be_valid)
+{
+	git_refspec refspec;
+	int error;
+
+	error = git_refspec__parse(&refspec, input, direction == GIT_DIR_FETCH);
+
+	if (is_expected_to_be_valid)
+		cl_assert_equal_i(0, error);
+	else
+		cl_assert_equal_i(GIT_ERROR, error);
+}
+
+void test_network_refspecs__parsing(void)
+{
+	// Ported from https://github.com/git/git/blob/abd2bde78bd994166900290434a2048e660dabed/t/t5511-refspec.sh
+
+	assert_refspec(GIT_DIR_PUSH, "", false);
+	assert_refspec(GIT_DIR_PUSH, ":", true);
+	assert_refspec(GIT_DIR_PUSH, "::", false);
+	assert_refspec(GIT_DIR_PUSH, "+:", true);
+
+	assert_refspec(GIT_DIR_FETCH, "", true);
+	assert_refspec(GIT_DIR_PUSH, ":", true);
+	assert_refspec(GIT_DIR_FETCH, "::", false);
+
+	assert_refspec(GIT_DIR_PUSH, "refs/heads/*:refs/remotes/frotz/*", true);
+	assert_refspec(GIT_DIR_PUSH, "refs/heads/*:refs/remotes/frotz", false);
+	assert_refspec(GIT_DIR_PUSH, "refs/heads:refs/remotes/frotz/*", false);
+	assert_refspec(GIT_DIR_PUSH, "refs/heads/master:refs/remotes/frotz/xyzzy", true);
+
+	/*
+	 * These have invalid LHS, but we do not have a formal "valid sha-1
+	 * expression syntax checker" so they are not checked with the current
+	 * code.  They will be caught downstream anyway, but we may want to
+	 * have tighter check later...
+	 */
+	//assert_refspec(GIT_DIR_PUSH, "refs/heads/master::refs/remotes/frotz/xyzzy", false);
+	//assert_refspec(GIT_DIR_PUSH, "refs/heads/maste :refs/remotes/frotz/xyzzy", false);
+
+	assert_refspec(GIT_DIR_FETCH, "refs/heads/*:refs/remotes/frotz/*", true);
+	assert_refspec(GIT_DIR_FETCH, "refs/heads/*:refs/remotes/frotz", false);
+	assert_refspec(GIT_DIR_FETCH, "refs/heads:refs/remotes/frotz/*", false);
+	assert_refspec(GIT_DIR_FETCH, "refs/heads/master:refs/remotes/frotz/xyzzy", true);
+	assert_refspec(GIT_DIR_FETCH, "refs/heads/master::refs/remotes/frotz/xyzzy", false);
+	assert_refspec(GIT_DIR_FETCH, "refs/heads/maste :refs/remotes/frotz/xyzzy", false);
+
+	assert_refspec(GIT_DIR_PUSH, "master~1:refs/remotes/frotz/backup", true);
+	assert_refspec(GIT_DIR_FETCH, "master~1:refs/remotes/frotz/backup", false);
+	assert_refspec(GIT_DIR_PUSH, "HEAD~4:refs/remotes/frotz/new", true);
+	assert_refspec(GIT_DIR_FETCH, "HEAD~4:refs/remotes/frotz/new", false);
+
+	assert_refspec(GIT_DIR_PUSH, "HEAD", true);
+	assert_refspec(GIT_DIR_FETCH, "HEAD", true);
+	assert_refspec(GIT_DIR_PUSH, "refs/heads/ nitfol", false);
+	assert_refspec(GIT_DIR_FETCH, "refs/heads/ nitfol", false);
+
+	assert_refspec(GIT_DIR_PUSH, "HEAD:", false);
+	assert_refspec(GIT_DIR_FETCH, "HEAD:", true);
+	assert_refspec(GIT_DIR_PUSH, "refs/heads/ nitfol:", false);
+	assert_refspec(GIT_DIR_FETCH, "refs/heads/ nitfol:", false);
+
+	assert_refspec(GIT_DIR_PUSH, ":refs/remotes/frotz/deleteme", true);
+	assert_refspec(GIT_DIR_FETCH, ":refs/remotes/frotz/HEAD-to-me", true);
+	assert_refspec(GIT_DIR_PUSH, ":refs/remotes/frotz/delete me", false);
+	assert_refspec(GIT_DIR_FETCH, ":refs/remotes/frotz/HEAD to me", false);
+
+	assert_refspec(GIT_DIR_FETCH, "refs/heads/*/for-linus:refs/remotes/mine/*-blah", false);
+	assert_refspec(GIT_DIR_PUSH, "refs/heads/*/for-linus:refs/remotes/mine/*-blah", false);
+
+	assert_refspec(GIT_DIR_FETCH, "refs/heads*/for-linus:refs/remotes/mine/*", false);
+	assert_refspec(GIT_DIR_PUSH, "refs/heads*/for-linus:refs/remotes/mine/*", false);
+
+	assert_refspec(GIT_DIR_FETCH, "refs/heads/*/*/for-linus:refs/remotes/mine/*", false);
+	assert_refspec(GIT_DIR_PUSH, "refs/heads/*/*/for-linus:refs/remotes/mine/*", false);
+
+	assert_refspec(GIT_DIR_FETCH, "refs/heads/*/for-linus:refs/remotes/mine/*", true);
+	assert_refspec(GIT_DIR_PUSH, "refs/heads/*/for-linus:refs/remotes/mine/*", true);
+}
diff --git a/tests-clar/refs/create.c b/tests-clar/refs/create.c
index 2e42cb6..af5b203 100644
--- a/tests-clar/refs/create.c
+++ b/tests-clar/refs/create.c
@@ -27,7 +27,7 @@ void test_refs_create__symbolic(void)
 	git_oid id;
 	git_buf ref_path = GIT_BUF_INIT;
 
-	const char *new_head_tracker = "another-head-tracker";
+	const char *new_head_tracker = "ANOTHER_HEAD_TRACKER";
 
 	git_oid_fromstr(&id, current_master_tip);
 
diff --git a/tests-clar/refs/isvalidname.c b/tests-clar/refs/isvalidname.c
new file mode 100644
index 0000000..99761de
--- /dev/null
+++ b/tests-clar/refs/isvalidname.c
@@ -0,0 +1,23 @@
+#include "clar_libgit2.h"
+
+void test_refs_isvalidname__can_detect_invalid_formats(void)
+{
+	cl_assert_equal_i(false, git_reference_is_valid_name("refs/tags/0.17.0^{}"));
+	cl_assert_equal_i(false, git_reference_is_valid_name("TWO/LEVELS"));
+	cl_assert_equal_i(false, git_reference_is_valid_name("ONE.LEVEL"));
+	cl_assert_equal_i(false, git_reference_is_valid_name("HEAD/"));
+	cl_assert_equal_i(false, git_reference_is_valid_name("NO_TRAILING_UNDERSCORE_"));
+	cl_assert_equal_i(false, git_reference_is_valid_name("_NO_LEADING_UNDERSCORE"));
+	cl_assert_equal_i(false, git_reference_is_valid_name("HEAD/aa"));
+	cl_assert_equal_i(false, git_reference_is_valid_name("lower_case"));
+	cl_assert_equal_i(false, git_reference_is_valid_name(""));
+}
+
+void test_refs_isvalidname__wont_hopefully_choke_on_valid_formats(void)
+{
+	cl_assert_equal_i(true, git_reference_is_valid_name("refs/tags/0.17.0"));
+	cl_assert_equal_i(true, git_reference_is_valid_name("refs/LEVELS"));
+	cl_assert_equal_i(true, git_reference_is_valid_name("HEAD"));
+	cl_assert_equal_i(true, git_reference_is_valid_name("ONE_LEVEL"));
+	cl_assert_equal_i(true, git_reference_is_valid_name("refs/stash"));
+}
diff --git a/tests-clar/refs/lookup.c b/tests-clar/refs/lookup.c
index ab563ac..71ab1b7 100644
--- a/tests-clar/refs/lookup.c
+++ b/tests-clar/refs/lookup.c
@@ -25,7 +25,7 @@ void test_refs_lookup__with_resolve(void)
 	cl_assert(git_reference_cmp(a, b) == 0);
 	git_reference_free(b);
 
-	cl_git_pass(git_reference_lookup_resolved(&b, g_repo, "head-tracker", 5));
+	cl_git_pass(git_reference_lookup_resolved(&b, g_repo, "HEAD_TRACKER", 5));
 	cl_assert(git_reference_cmp(a, b) == 0);
 	git_reference_free(b);
 
diff --git a/tests-clar/refs/normalize.c b/tests-clar/refs/normalize.c
index 4e80e4b..a144ef5 100644
--- a/tests-clar/refs/normalize.c
+++ b/tests-clar/refs/normalize.c
@@ -5,9 +5,10 @@
 #include "reflog.h"
 
 // Helpers
-static void ensure_refname_normalized(unsigned int flags,
-                                      const char *input_refname,
-                                      const char *expected_refname)
+static void ensure_refname_normalized(
+	unsigned int flags,
+	const char *input_refname,
+	const char *expected_refname)
 {
 	char buffer_out[GIT_REFNAME_MAX];
 
@@ -38,17 +39,7 @@ void test_refs_normalize__can_normalize_a_direct_reference_name(void)
 	ensure_refname_normalized(
 		GIT_REF_FORMAT_NORMAL, "refs/heads/v@ation", "refs/heads/v@ation");
 	ensure_refname_normalized(
-		GIT_REF_FORMAT_NORMAL, "/refs///heads///a", "refs/heads/a");
-}
-
-void test_refs_normalize__can_normalize_some_specific_one_level_direct_reference_names(void)
-{
-	ensure_refname_normalized(
-		GIT_REF_FORMAT_NORMAL, "HEAD", "HEAD");
-	ensure_refname_normalized(
-		GIT_REF_FORMAT_NORMAL, "MERGE_HEAD", "MERGE_HEAD");
-	ensure_refname_normalized(
-		GIT_REF_FORMAT_NORMAL, "FETCH_HEAD", "FETCH_HEAD");
+		GIT_REF_FORMAT_NORMAL, "refs///heads///a", "refs/heads/a");
 }
 
 void test_refs_normalize__cannot_normalize_any_direct_reference_name(void)
@@ -62,6 +53,8 @@ void test_refs_normalize__cannot_normalize_any_direct_reference_name(void)
 	ensure_refname_invalid(
 		GIT_REF_FORMAT_NORMAL, "");
 	ensure_refname_invalid(
+		GIT_REF_FORMAT_NORMAL, "/refs/heads/a/");
+	ensure_refname_invalid(
 		GIT_REF_FORMAT_NORMAL, "refs/heads/a/");
 	ensure_refname_invalid(
 		GIT_REF_FORMAT_NORMAL, "refs/heads/a.");
@@ -97,9 +90,9 @@ void test_refs_normalize__symbolic(void)
 		GIT_REF_FORMAT_ALLOW_ONELEVEL, "///");
 
 	ensure_refname_normalized(
-		GIT_REF_FORMAT_ALLOW_ONELEVEL, "a", "a");
+		GIT_REF_FORMAT_ALLOW_ONELEVEL, "ALL_CAPS_AND_UNDERSCORES", "ALL_CAPS_AND_UNDERSCORES");
 	ensure_refname_normalized(
-		GIT_REF_FORMAT_ALLOW_ONELEVEL, "a/b", "a/b");
+		GIT_REF_FORMAT_ALLOW_ONELEVEL, "refs/MixedCasing", "refs/MixedCasing");
 	ensure_refname_normalized(
 		GIT_REF_FORMAT_ALLOW_ONELEVEL, "refs///heads///a", "refs/heads/a");
 
@@ -115,7 +108,7 @@ void test_refs_normalize__symbolic(void)
  * See https://github.com/spearce/JGit/commit/e4bf8f6957bbb29362575d641d1e77a02d906739 */
 void test_refs_normalize__jgit_suite(void)
 {
-   // tests borrowed from JGit
+	// tests borrowed from JGit
 
 /* EmptyString */
 	ensure_refname_invalid(
@@ -127,10 +120,9 @@ void test_refs_normalize__jgit_suite(void)
 	ensure_refname_invalid(
 		GIT_REF_FORMAT_NORMAL, "master");
 	ensure_refname_normalized(
-		GIT_REF_FORMAT_ALLOW_ONELEVEL, "heads/master", "heads/master");
+		GIT_REF_FORMAT_NORMAL, "heads/master", "heads/master");
 
 /* ValidHead */
-
 	ensure_refname_normalized(
 		GIT_REF_FORMAT_ALLOW_ONELEVEL, "refs/heads/master", "refs/heads/master");
 	ensure_refname_normalized(
@@ -310,7 +302,61 @@ void test_refs_normalize__buffer_has_to_be_big_enough_to_hold_the_normalized_ver
 	char buffer_out[21];
 
 	cl_git_pass(git_reference_normalize_name(
-		buffer_out, 21, "//refs//heads/long///name", GIT_REF_FORMAT_NORMAL));
+		buffer_out, 21, "refs//heads///long///name", GIT_REF_FORMAT_NORMAL));
 	cl_git_fail(git_reference_normalize_name(
-		buffer_out, 20, "//refs//heads/long///name", GIT_REF_FORMAT_NORMAL));
+		buffer_out, 20, "refs//heads///long///name", GIT_REF_FORMAT_NORMAL));
+}
+
+#define ONE_LEVEL_AND_REFSPEC \
+	GIT_REF_FORMAT_ALLOW_ONELEVEL \
+	| GIT_REF_FORMAT_REFSPEC_PATTERN
+
+void test_refs_normalize__refspec_pattern(void)
+{
+	ensure_refname_invalid(
+		GIT_REF_FORMAT_REFSPEC_PATTERN, "heads/*foo/bar");
+	ensure_refname_invalid(
+		GIT_REF_FORMAT_REFSPEC_PATTERN, "heads/foo*/bar");
+	ensure_refname_invalid(
+		GIT_REF_FORMAT_REFSPEC_PATTERN, "heads/f*o/bar");
+
+	ensure_refname_invalid(
+		GIT_REF_FORMAT_REFSPEC_PATTERN, "foo");
+	ensure_refname_normalized(
+		ONE_LEVEL_AND_REFSPEC, "FOO", "FOO");
+
+	ensure_refname_normalized(
+		GIT_REF_FORMAT_REFSPEC_PATTERN, "foo/bar", "foo/bar");
+	ensure_refname_normalized(
+		ONE_LEVEL_AND_REFSPEC, "foo/bar", "foo/bar");
+
+	ensure_refname_normalized(
+		GIT_REF_FORMAT_REFSPEC_PATTERN, "*/foo", "*/foo");
+	ensure_refname_normalized(
+		ONE_LEVEL_AND_REFSPEC, "*/foo", "*/foo");
+
+	ensure_refname_normalized(
+		GIT_REF_FORMAT_REFSPEC_PATTERN, "foo/*/bar", "foo/*/bar");
+	ensure_refname_normalized(
+		ONE_LEVEL_AND_REFSPEC, "foo/*/bar", "foo/*/bar");
+
+	ensure_refname_invalid(
+		GIT_REF_FORMAT_REFSPEC_PATTERN, "*");
+	ensure_refname_normalized(
+		ONE_LEVEL_AND_REFSPEC, "*", "*");
+
+	ensure_refname_invalid(
+		GIT_REF_FORMAT_REFSPEC_PATTERN, "foo/*/*");
+	ensure_refname_invalid(
+		ONE_LEVEL_AND_REFSPEC, "foo/*/*");
+
+	ensure_refname_invalid(
+		GIT_REF_FORMAT_REFSPEC_PATTERN, "*/foo/*");
+	ensure_refname_invalid(
+		ONE_LEVEL_AND_REFSPEC, "*/foo/*");
+
+	ensure_refname_invalid(
+		GIT_REF_FORMAT_REFSPEC_PATTERN, "*/*/foo");
+	ensure_refname_invalid(
+		ONE_LEVEL_AND_REFSPEC, "*/*/foo");
 }
diff --git a/tests-clar/refs/read.c b/tests-clar/refs/read.c
index f336587..6ab6bf5 100644
--- a/tests-clar/refs/read.c
+++ b/tests-clar/refs/read.c
@@ -6,7 +6,7 @@
 
 static const char *loose_tag_ref_name = "refs/tags/e90810b";
 static const char *non_existing_tag_ref_name = "refs/tags/i-do-not-exist";
-static const char *head_tracker_sym_ref_name = "head-tracker";
+static const char *head_tracker_sym_ref_name = "HEAD_TRACKER";
 static const char *current_head_target = "refs/heads/master";
 static const char *current_master_tip = "a65fedf39aefe402d3bb6e24df4d4f5fe4547750";
 static const char *packed_head_name = "refs/heads/packed";
@@ -221,7 +221,7 @@ void test_refs_read__unfound_return_ENOTFOUND(void)
 {
 	git_reference *reference;
 
-	cl_assert_equal_i(GIT_ENOTFOUND, git_reference_lookup(&reference, g_repo, "test/master"));
+	cl_assert_equal_i(GIT_ENOTFOUND, git_reference_lookup(&reference, g_repo, "TEST_MASTER"));
 	cl_assert_equal_i(GIT_ENOTFOUND, git_reference_lookup(&reference, g_repo, "refs/test/master"));
 	cl_assert_equal_i(GIT_ENOTFOUND, git_reference_lookup(&reference, g_repo, "refs/tags/test/master"));
 	cl_assert_equal_i(GIT_ENOTFOUND, git_reference_lookup(&reference, g_repo, "refs/tags/test/farther/master"));
diff --git a/tests-clar/resources/testrepo.git/HEAD_TRACKER b/tests-clar/resources/testrepo.git/HEAD_TRACKER
new file mode 100644
index 0000000..40d876b
--- /dev/null
+++ b/tests-clar/resources/testrepo.git/HEAD_TRACKER
@@ -0,0 +1 @@
+ref: HEAD
diff --git a/tests-clar/resources/testrepo.git/head-tracker b/tests-clar/resources/testrepo.git/head-tracker
deleted file mode 100644
index 40d876b..0000000
--- a/tests-clar/resources/testrepo.git/head-tracker
+++ /dev/null
@@ -1 +0,0 @@
-ref: HEAD
diff --git a/tests-clar/resources/testrepo/.gitted/HEAD_TRACKER b/tests-clar/resources/testrepo/.gitted/HEAD_TRACKER
new file mode 100644
index 0000000..40d876b
--- /dev/null
+++ b/tests-clar/resources/testrepo/.gitted/HEAD_TRACKER
@@ -0,0 +1 @@
+ref: HEAD
diff --git a/tests-clar/resources/testrepo/.gitted/head-tracker b/tests-clar/resources/testrepo/.gitted/head-tracker
deleted file mode 100644
index 40d876b..0000000
--- a/tests-clar/resources/testrepo/.gitted/head-tracker
+++ /dev/null
@@ -1 +0,0 @@
-ref: HEAD