Merge pull request libgit2#6962 from ryan-ph/ryanpham/negative-refspec/remote

remote: Handle fetching negative refspecs

Author: ethomson

include/git2/refspec.h

@@ -78,6 +78,15 @@ GIT_EXTERN(int) git_refspec_force(const git_refspec *refspec);
  */
 GIT_EXTERN(git_direction) git_refspec_direction(const git_refspec *spec);
 
+/**
+ * Check if a refspec's source descriptor matches a negative reference
+ *
+ * @param refspec the refspec
+ * @param refname the name of the reference to check
+ * @return 1 if the refspec matches, 0 otherwise
+ */
+GIT_EXTERN(int) git_refspec_src_matches_negative(const git_refspec *refspec, const char *refname);
+
 /**
  * Check if a refspec's source descriptor matches a reference
  *

src/libgit2/refspec.c

@@ -22,6 +22,7 @@ int git_refspec__parse(git_refspec *refspec, const char *input, bool is_fetch)
 	const char *lhs, *rhs;
 	int valid = 0;
 	unsigned int flags;
+	bool is_neg_refspec = false;
 
 	GIT_ASSERT_ARG(refspec);
 	GIT_ASSERT_ARG(input);
@@ -34,6 +35,9 @@ int git_refspec__parse(git_refspec *refspec, const char *input, bool is_fetch)
 		refspec->force = 1;
 		lhs++;
 	}
+	if (*lhs == '^') {
+		is_neg_refspec = true;
+	}
 
 	rhs = strrchr(lhs, ':');
 
@@ -62,7 +66,14 @@ int git_refspec__parse(git_refspec *refspec, const char *input, bool is_fetch)
 
 	llen = (rhs ? (size_t)(rhs - lhs - 1) : strlen(lhs));
 	if (1 <= llen && memchr(lhs, '*', llen)) {
-		if ((rhs && !is_glob) || (!rhs && is_fetch))
+		/*
+		 * If the lefthand side contains a glob, then one of the following must be
+		 * true, otherwise the spec is invalid
+		 *   1) the rhs exists and also contains a glob
+		 *   2) it is a negative refspec (i.e. no rhs)
+		 *   3) the rhs doesn't exist and we're fetching
+		 */
+		if ((rhs && !is_glob) || (rhs && is_neg_refspec) || (!rhs && is_fetch && !is_neg_refspec))
 			goto invalid;
 		is_glob = 1;
 	} else if (rhs && is_glob)
@@ -225,6 +236,14 @@ int git_refspec_force(const git_refspec *refspec)
 	return refspec->force;
 }
 
+int git_refspec_src_matches_negative(const git_refspec *refspec, const char *refname)
+{
+	if (refspec == NULL || refspec->src == NULL || !git_refspec_is_negative(refspec))
+		return false;
+
+	return (wildmatch(refspec->src + 1, refname, 0) == 0);
+}
+
 int git_refspec_src_matches(const git_refspec *refspec, const char *refname)
 {
 	if (refspec == NULL || refspec->src == NULL)
@@ -340,6 +359,14 @@ int git_refspec_is_wildcard(const git_refspec *spec)
 	return (spec->src[strlen(spec->src) - 1] == '*');
 }
 
+int git_refspec_is_negative(const git_refspec *spec)
+{
+	GIT_ASSERT_ARG(spec);
+	GIT_ASSERT_ARG(spec->src);
+
+	return (spec->src[0] == '^' && spec->dst == NULL);
+}
+
 git_direction git_refspec_direction(const git_refspec *spec)
 {
 	GIT_ASSERT_ARG(spec);

src/libgit2/refspec.h

@@ -45,6 +45,14 @@ int git_refspec__serialize(git_str *out, const git_refspec *refspec);
  */
 int git_refspec_is_wildcard(const git_refspec *spec);
 
+/**
+ * Determines if a refspec is a negative refspec.
+ *
+ * @param spec the refspec
+ * @return 1 if the refspec is a negative, 0 otherwise
+ */
+int git_refspec_is_negative(const git_refspec *spec);
+
 /**
  * DWIM `spec` with `refs` existing on the remote, append the dwim'ed
  * result in `out`.

src/libgit2/remote.c

@@ -2628,17 +2628,21 @@ int git_remote_name_is_valid(int *valid, const char *remote_name)
 git_refspec *git_remote__matching_refspec(git_remote *remote, const char *refname)
 {
 	git_refspec *spec;
+	git_refspec *match = NULL;
 	size_t i;
 
 	git_vector_foreach(&remote->active_refspecs, i, spec) {
 		if (spec->push)
 			continue;
 
-		if (git_refspec_src_matches(spec, refname))
-			return spec;
+		if (git_refspec_src_matches_negative(spec, refname))
+			return NULL;
+
+		if (git_refspec_src_matches(spec, refname) && match == NULL)
+			match = spec;
 	}
 
-	return NULL;
+	return match;
 }
 
 git_refspec *git_remote__matching_dst_refspec(git_remote *remote, const char *refname)

tests/libgit2/refs/normalize.c

@@ -402,6 +402,8 @@ void test_refs_normalize__negative_refspec_pattern(void)
 {
 	ensure_refname_normalized(
 		GIT_REFERENCE_FORMAT_REFSPEC_PATTERN, "^foo/bar", "^foo/bar");
+	ensure_refname_normalized(
+		GIT_REFERENCE_FORMAT_REFSPEC_PATTERN, "^foo/bar/*", "^foo/bar/*");
 	ensure_refname_invalid(
 		GIT_REFERENCE_FORMAT_REFSPEC_PATTERN, "foo/^bar");
 }

tests/libgit2/remote/fetch.c

@@ -10,8 +10,11 @@ static char* repo2_path;
 
 static const char *REPO1_REFNAME = "refs/heads/main";
 static const char *REPO2_REFNAME = "refs/remotes/repo1/main";
+static const char *REPO1_UNDERSCORE_REFNAME = "refs/heads/_branch";
+static const char *REPO2_UNDERSCORE_REFNAME = "refs/remotes/repo1/_branch";
 static char *FORCE_FETCHSPEC = "+refs/heads/main:refs/remotes/repo1/main";
 static char *NON_FORCE_FETCHSPEC = "refs/heads/main:refs/remotes/repo1/main";
+static char *NEGATIVE_SPEC = "^refs/heads/_*";
 
 void test_remote_fetch__initialize(void) {
 	git_config *c;
@@ -170,3 +173,61 @@ void test_remote_fetch__do_update_refs_if_not_descendant_and_force(void) {
 
 	git_reference_free(ref);
 }
+
+/**
+ * This checks that negative refspecs are respected when fetching. We create a
+ * repository with a '_' prefixed reference. A second repository is configured
+ * with a negative refspec to ignore any refs prefixed with '_' and fetch the
+ * first repository into the second.
+ *
+ * @param commit1id A pointer to an OID which will be populated with the first
+ *                  commit.
+ */
+static void do_fetch_repo_with_ref_matching_negative_refspec(git_oid *commit1id) {
+	/* create a commit in repo 1 and a reference to it with '_' prefix */
+	{
+		git_oid empty_tree_id;
+		git_tree *empty_tree;
+		git_signature *sig;
+		git_treebuilder *tb;
+		cl_git_pass(git_treebuilder_new(&tb, repo1, NULL));
+		cl_git_pass(git_treebuilder_write(&empty_tree_id, tb));
+		cl_git_pass(git_tree_lookup(&empty_tree, repo1, &empty_tree_id));
+		cl_git_pass(git_signature_default(&sig, repo1));
+		cl_git_pass(git_commit_create(commit1id, repo1, REPO1_UNDERSCORE_REFNAME, sig,
+					sig, NULL, "one", empty_tree, 0, NULL));
+
+		git_tree_free(empty_tree);
+		git_signature_free(sig);
+		git_treebuilder_free(tb);
+	}
+
+	/* fetch the remote with negative refspec for references prefixed with '_' */
+	{
+		char *refspec_strs = { NEGATIVE_SPEC };
+		git_strarray refspecs = { &refspec_strs, 1 };
+
+		git_remote *remote;
+
+		cl_git_pass(git_remote_create_anonymous(&remote, repo2,
+					git_repository_path(repo1)));
+		cl_git_pass(git_remote_fetch(remote, &refspecs, NULL, "some message"));
+
+		git_remote_free(remote);
+	}
+}
+
+void test_remote_fetch__skip_negative_refspec_match(void) {
+	git_oid commit1id;
+	git_reference *ref1;
+	git_reference *ref2;
+
+	do_fetch_repo_with_ref_matching_negative_refspec(&commit1id);
+
+	/* assert that the reference in exists in repo1 but not in repo2 */
+	cl_git_pass(git_reference_lookup(&ref1, repo1, REPO1_UNDERSCORE_REFNAME));
+	cl_assert_equal_b(git_reference_lookup(&ref2, repo2, REPO2_UNDERSCORE_REFNAME), GIT_ENOTFOUND);
+
+	git_reference_free(ref1);
+	git_reference_free(ref2);
+}