thodg/libgit2

diff --git a/include/git2/filter.h b/include/git2/filter.h
index f96b676..7fd9b7e 100644
--- a/include/git2/filter.h
+++ b/include/git2/filter.h
@@ -35,6 +35,11 @@ typedef enum {
 	GIT_FILTER_CLEAN = GIT_FILTER_TO_ODB,
 } git_filter_mode_t;
 
+typedef enum {
+	GIT_FILTER_OPT_DEFAULT = 0u,
+	GIT_FILTER_OPT_ALLOW_UNSAFE = (1u << 0),
+} git_filter_opt_t;
+
 /**
  * A filter that can transform file data
  *
@@ -83,7 +88,8 @@ GIT_EXTERN(int) git_filter_list_load(
 	git_repository *repo,
 	git_blob *blob, /* can be NULL */
 	const char *path,
-	git_filter_mode_t mode);
+	git_filter_mode_t mode,
+	git_filter_opt_t options);
 
 /**
  * Apply filter list to a data buffer.
diff --git a/include/git2/repository.h b/include/git2/repository.h
index e3f687a..04df25f 100644
--- a/include/git2/repository.h
+++ b/include/git2/repository.h
@@ -546,6 +546,10 @@ GIT_EXTERN(int) git_repository_mergehead_foreach(
  * hash a file in the repository and you want to apply filtering rules (e.g.
  * crlf filters) before generating the SHA, then use this function.
  *
+ * Note: if the repository has `core.safecrlf` set to fail and the
+ * filtering triggers that failure, then this function will return an
+ * error and not calculate the hash of the file.
+ *
  * @param out Output value of calculated SHA
  * @param repo Repository pointer
  * @param path Path to file on disk whose contents should be hashed. If the
@@ -555,6 +559,7 @@ GIT_EXTERN(int) git_repository_mergehead_foreach(
  *             NULL, then the `path` parameter will be used instead. If
  *             this is passed as the empty string, then no filters will be
  *             applied when calculating the hash.
+ * @return 0 on success, or an error code
  */
 GIT_EXTERN(int) git_repository_hashfile(
 	git_oid *out,
diff --git a/include/git2/sys/filter.h b/include/git2/sys/filter.h
index 8fe21c9..1b21a9d 100644
--- a/include/git2/sys/filter.h
+++ b/include/git2/sys/filter.h
@@ -55,7 +55,10 @@ GIT_EXTERN(git_filter *) git_filter_lookup(const char *name);
  * your own chains of filters.
  */
 GIT_EXTERN(int) git_filter_list_new(
-	git_filter_list **out, git_repository *repo, git_filter_mode_t mode);
+	git_filter_list **out,
+	git_repository *repo,
+	git_filter_mode_t mode,
+	git_filter_opt_t options);
 
 /**
  * Add a filter to a filter list with the given payload.
@@ -115,10 +118,15 @@ GIT_EXTERN(uint16_t) git_filter_source_filemode(const git_filter_source *src);
 GIT_EXTERN(const git_oid *) git_filter_source_id(const git_filter_source *src);
 
 /**
- * Get the git_filter_mode_t to be applied
+ * Get the git_filter_mode_t to be used
  */
 GIT_EXTERN(git_filter_mode_t) git_filter_source_mode(const git_filter_source *src);
 
+/**
+ * Get the git_filter_opt_t options to be applied
+ */
+GIT_EXTERN(git_filter_opt_t) git_filter_source_options(const git_filter_source *src);
+
 /*
  * struct git_filter
  *
diff --git a/src/blob.c b/src/blob.c
index 0aa2516..ab7dec6 100644
--- a/src/blob.c
+++ b/src/blob.c
@@ -198,7 +198,8 @@ int git_blob__create_from_paths(
 		if (try_load_filters)
 			/* Load the filters for writing this file to the ODB */
 			error = git_filter_list_load(
-				&fl, repo, NULL, hint_path, GIT_FILTER_TO_ODB);
+				&fl, repo, NULL, hint_path,
+				GIT_FILTER_TO_ODB, GIT_FILTER_OPT_DEFAULT);
 
 		if (error < 0)
 			/* well, that didn't work */;
@@ -356,7 +357,8 @@ int git_blob_filtered_content(
 		return 0;
 
 	if (!(error = git_filter_list_load(
-			&fl, git_blob_owner(blob), blob, path, GIT_FILTER_TO_WORKTREE))) {
+			&fl, git_blob_owner(blob), blob, path,
+			GIT_FILTER_TO_WORKTREE, GIT_FILTER_OPT_DEFAULT))) {
 
 		error = git_filter_list_apply_to_blob(out, fl, blob);
 
diff --git a/src/checkout.c b/src/checkout.c
index b869efe..20763fd 100644
--- a/src/checkout.c
+++ b/src/checkout.c
@@ -1212,7 +1212,8 @@ static int blob_content_to_file(
 
 	if (!opts->disable_filters)
 		error = git_filter_list_load(
-			&fl, git_blob_owner(blob), blob, hint_path, GIT_FILTER_TO_WORKTREE);
+			&fl, git_blob_owner(blob), blob, hint_path,
+			GIT_FILTER_TO_WORKTREE, GIT_FILTER_OPT_DEFAULT);
 
 	if (!error)
 		error = git_filter_list_apply_to_blob(&out, fl, blob);
diff --git a/src/crlf.c b/src/crlf.c
index 8be1b9a..dad3ece 100644
--- a/src/crlf.c
+++ b/src/crlf.c
@@ -139,10 +139,19 @@ static int crlf_apply_to_odb(
 			return GIT_PASSTHROUGH;
 
 		/* If safecrlf is enabled, sanity-check the result. */
-		if (ca->safe_crlf && (stats.cr != stats.crlf || stats.lf != stats.crlf)) {
-			giterr_set(GITERR_FILTER, "LF would be replaced by CRLF in '%s'",
-				git_filter_source_path(src));
-			return -1;
+		if (stats.cr != stats.crlf || stats.lf != stats.crlf) {
+			switch (ca->safe_crlf) {
+			case GIT_SAFE_CRLF_FAIL:
+				giterr_set(
+					GITERR_FILTER, "LF would be replaced by CRLF in '%s'",
+					git_filter_source_path(src));
+				return -1;
+			case GIT_SAFE_CRLF_WARN:
+				/* TODO: issue warning when warning API is available */;
+				break;
+			default:
+				break;
+			}
 		}
 
 		/*
@@ -267,6 +276,7 @@ static int crlf_check(
 	if (ca.crlf_action == GIT_CRLF_GUESS ||
 		(ca.crlf_action == GIT_CRLF_AUTO &&
 		git_filter_source_mode(src) == GIT_FILTER_SMUDGE)) {
+
 		error = git_repository__cvar(
 			&ca.auto_crlf, git_filter_source_repo(src), GIT_CVAR_AUTO_CRLF);
 		if (error < 0)
@@ -285,6 +295,11 @@ static int crlf_check(
 			&ca.safe_crlf, git_filter_source_repo(src), GIT_CVAR_SAFE_CRLF);
 		if (error < 0)
 			return error;
+
+		/* downgrade FAIL to WARN if ALLOW_UNSAFE option is used */
+		if ((git_filter_source_options(src) & GIT_FILTER_OPT_ALLOW_UNSAFE) &&
+			ca.safe_crlf == GIT_SAFE_CRLF_FAIL)
+			ca.safe_crlf = GIT_SAFE_CRLF_WARN;
 	}
 
 	*payload = git__malloc(sizeof(ca));
diff --git a/src/diff.c b/src/diff.c
index 781f23e..bc23e6b 100644
--- a/src/diff.c
+++ b/src/diff.c
@@ -589,7 +589,8 @@ int git_diff__oid_for_entry(
 			entry.path);
 		error = -1;
 	} else if (!(error = git_filter_list_load(
-			&fl, diff->repo, NULL, entry.path, GIT_FILTER_TO_ODB)))
+		&fl, diff->repo, NULL, entry.path,
+		GIT_FILTER_TO_ODB, GIT_FILTER_OPT_ALLOW_UNSAFE)))
 	{
 		int fd = git_futils_open_ro(full_path.ptr);
 		if (fd < 0)
diff --git a/src/diff_file.c b/src/diff_file.c
index b9f92df..f2a1d50 100644
--- a/src/diff_file.c
+++ b/src/diff_file.c
@@ -300,7 +300,8 @@ static int diff_file_content_load_workdir_file(
 		goto cleanup;
 
 	if ((error = git_filter_list_load(
-			&fl, fc->repo, NULL, fc->file->path, GIT_FILTER_TO_ODB)) < 0)
+			&fl, fc->repo, NULL, fc->file->path,
+			GIT_FILTER_TO_ODB, GIT_FILTER_OPT_ALLOW_UNSAFE)) < 0)
 		goto cleanup;
 
 	/* if there are no filters, try to mmap the file */
diff --git a/src/filter.c b/src/filter.c
index b2f5796..b0e2b8b 100644
--- a/src/filter.c
+++ b/src/filter.c
@@ -23,6 +23,7 @@ struct git_filter_source {
 	git_oid         oid;  /* zero if unknown (which is likely) */
 	uint16_t        filemode; /* zero if unknown */
 	git_filter_mode_t mode;
+	git_filter_opt_t  options;
 };
 
 typedef struct {
@@ -358,6 +359,11 @@ git_filter_mode_t git_filter_source_mode(const git_filter_source *src)
 	return src->mode;
 }
 
+git_filter_opt_t git_filter_source_options(const git_filter_source *src)
+{
+	return src->options;
+}
+
 static int filter_list_new(
 	git_filter_list **out, const git_filter_source *src)
 {
@@ -372,6 +378,7 @@ static int filter_list_new(
 	fl->source.repo = src->repo;
 	fl->source.path = fl->path;
 	fl->source.mode = src->mode;
+	fl->source.options = src->options;
 
 	*out = fl;
 	return 0;
@@ -419,12 +426,16 @@ static int filter_list_check_attributes(
 }
 
 int git_filter_list_new(
-	git_filter_list **out, git_repository *repo, git_filter_mode_t mode)
+	git_filter_list **out,
+	git_repository *repo,
+	git_filter_mode_t mode,
+	git_filter_opt_t options)
 {
 	git_filter_source src = { 0 };
 	src.repo = repo;
 	src.path = NULL;
 	src.mode = mode;
+	src.options = options;
 	return filter_list_new(out, &src);
 }
 
@@ -433,7 +444,8 @@ int git_filter_list_load(
 	git_repository *repo,
 	git_blob *blob, /* can be NULL */
 	const char *path,
-	git_filter_mode_t mode)
+	git_filter_mode_t mode,
+	git_filter_opt_t options)
 {
 	int error = 0;
 	git_filter_list *fl = NULL;
@@ -448,6 +460,7 @@ int git_filter_list_load(
 	src.repo = repo;
 	src.path = path;
 	src.mode = mode;
+	src.options = options;
 	if (blob)
 		git_oid_cpy(&src.oid, git_blob_id(blob));
 
diff --git a/src/repository.c b/src/repository.c
index ac7af76..df5f322 100644
--- a/src/repository.c
+++ b/src/repository.c
@@ -1789,7 +1789,8 @@ int git_repository_hashfile(
 	/* passing empty string for "as_path" indicated --no-filters */
 	if (strlen(as_path) > 0) {
 		error = git_filter_list_load(
-			&fl, repo, NULL, as_path, GIT_FILTER_TO_ODB);
+			&fl, repo, NULL, as_path,
+			GIT_FILTER_TO_ODB, GIT_FILTER_OPT_DEFAULT);
 		if (error < 0)
 			return error;
 	} else {
diff --git a/tests/filter/crlf.c b/tests/filter/crlf.c
index 75320ef..66c267e 100644
--- a/tests/filter/crlf.c
+++ b/tests/filter/crlf.c
@@ -25,7 +25,8 @@ void test_filter_crlf__to_worktree(void)
 	git_filter *crlf;
 	git_buf in = { 0 }, out = { 0 };
 
-	cl_git_pass(git_filter_list_new(&fl, g_repo, GIT_FILTER_TO_WORKTREE));
+	cl_git_pass(git_filter_list_new(
+		&fl, g_repo, GIT_FILTER_TO_WORKTREE, 0));
 
 	crlf = git_filter_lookup(GIT_FILTER_CRLF);
 	cl_assert(crlf != NULL);
@@ -53,7 +54,8 @@ void test_filter_crlf__to_odb(void)
 	git_filter *crlf;
 	git_buf in = { 0 }, out = { 0 };
 
-	cl_git_pass(git_filter_list_new(&fl, g_repo, GIT_FILTER_TO_ODB));
+	cl_git_pass(git_filter_list_new(
+		&fl, g_repo, GIT_FILTER_TO_ODB, 0));
 
 	crlf = git_filter_lookup(GIT_FILTER_CRLF);
 	cl_assert(crlf != NULL);
@@ -79,7 +81,8 @@ void test_filter_crlf__with_safecrlf(void)
 
 	cl_repo_set_bool(g_repo, "core.safecrlf", true);
 
-	cl_git_pass(git_filter_list_new(&fl, g_repo, GIT_FILTER_TO_ODB));
+	cl_git_pass(git_filter_list_new(
+		&fl, g_repo, GIT_FILTER_TO_ODB, 0));
 
 	crlf = git_filter_lookup(GIT_FILTER_CRLF);
 	cl_assert(crlf != NULL);
@@ -111,13 +114,57 @@ void test_filter_crlf__with_safecrlf(void)
 	git_buf_free(&out);
 }
 
+void test_filter_crlf__with_safecrlf_and_unsafe_allowed(void)
+{
+	git_filter_list *fl;
+	git_filter *crlf;
+	git_buf in = {0}, out = GIT_BUF_INIT;
+
+	cl_repo_set_bool(g_repo, "core.safecrlf", true);
+
+	cl_git_pass(git_filter_list_new(
+		&fl, g_repo, GIT_FILTER_TO_ODB, GIT_FILTER_OPT_ALLOW_UNSAFE));
+
+	crlf = git_filter_lookup(GIT_FILTER_CRLF);
+	cl_assert(crlf != NULL);
+
+	cl_git_pass(git_filter_list_push(fl, crlf, NULL));
+
+	/* Normalized \r\n succeeds with safecrlf */
+	in.ptr = "Normal\r\nCRLF\r\nline-endings.\r\n";
+	in.size = strlen(in.ptr);
+
+	cl_git_pass(git_filter_list_apply_to_data(&out, fl, &in));
+	cl_assert_equal_s("Normal\nCRLF\nline-endings.\n", out.ptr);
+
+	/* Mix of line endings fails with safecrlf, but allowed to pass */
+	in.ptr = "Mixed\nup\r\nLF\nand\r\nCRLF\nline-endings.\r\n";
+	in.size = strlen(in.ptr);
+
+	cl_git_pass(git_filter_list_apply_to_data(&out, fl, &in));
+	/* TODO: check for warning */
+	cl_assert_equal_s("Mixed\nup\nLF\nand\nCRLF\nline-endings.\n", out.ptr);
+
+	/* Normalized \n fails with safecrlf, but allowed to pass */
+	in.ptr = "Normal\nLF\nonly\nline-endings.\n";
+	in.size = strlen(in.ptr);
+
+	cl_git_pass(git_filter_list_apply_to_data(&out, fl, &in));
+	/* TODO: check for warning */
+	cl_assert_equal_s("Normal\nLF\nonly\nline-endings.\n", out.ptr);
+
+	git_filter_list_free(fl);
+	git_buf_free(&out);
+}
+
 void test_filter_crlf__no_safecrlf(void)
 {
 	git_filter_list *fl;
 	git_filter *crlf;
 	git_buf in = {0}, out = GIT_BUF_INIT;
 
-	cl_git_pass(git_filter_list_new(&fl, g_repo, GIT_FILTER_TO_ODB));
+	cl_git_pass(git_filter_list_new(
+		&fl, g_repo, GIT_FILTER_TO_ODB, 0));
 
 	crlf = git_filter_lookup(GIT_FILTER_CRLF);
 	cl_assert(crlf != NULL);
diff --git a/tests/filter/custom.c b/tests/filter/custom.c
index 7052401..0fd7c37 100644
--- a/tests/filter/custom.c
+++ b/tests/filter/custom.c
@@ -194,7 +194,7 @@ void test_filter_custom__to_odb(void)
 	git_buf in = GIT_BUF_INIT_CONST(workdir_data, strlen(workdir_data));
 
 	cl_git_pass(git_filter_list_load(
-		&fl, g_repo, NULL, "herofile", GIT_FILTER_TO_ODB));
+		&fl, g_repo, NULL, "herofile", GIT_FILTER_TO_ODB, 0));
 
 	cl_git_pass(git_filter_list_apply_to_data(&out, fl, &in));
 
@@ -215,7 +215,7 @@ void test_filter_custom__to_workdir(void)
 		bitflipped_and_reversed_data, BITFLIPPED_AND_REVERSED_DATA_LEN);
 
 	cl_git_pass(git_filter_list_load(
-		&fl, g_repo, NULL, "herofile", GIT_FILTER_TO_WORKTREE));
+		&fl, g_repo, NULL, "herofile", GIT_FILTER_TO_WORKTREE, 0));
 
 	cl_git_pass(git_filter_list_apply_to_data(&out, fl, &in));
 
@@ -233,13 +233,13 @@ void test_filter_custom__can_register_a_custom_filter_in_the_repository(void)
 	git_filter_list *fl;
 
 	cl_git_pass(git_filter_list_load(
-		&fl, g_repo, NULL, "herofile", GIT_FILTER_TO_WORKTREE));
+		&fl, g_repo, NULL, "herofile", GIT_FILTER_TO_WORKTREE, 0));
 	/* expect: bitflip, reverse, crlf */
 	cl_assert_equal_sz(3, git_filter_list_length(fl));
 	git_filter_list_free(fl);
 
 	cl_git_pass(git_filter_list_load(
-		&fl, g_repo, NULL, "herocorp", GIT_FILTER_TO_WORKTREE));
+		&fl, g_repo, NULL, "herocorp", GIT_FILTER_TO_WORKTREE, 0));
 	/* expect: bitflip, reverse - possibly crlf depending on global config */
 	{
 		size_t flen = git_filter_list_length(fl);
@@ -248,19 +248,20 @@ void test_filter_custom__can_register_a_custom_filter_in_the_repository(void)
 	git_filter_list_free(fl);
 
 	cl_git_pass(git_filter_list_load(
-		&fl, g_repo, NULL, "hero.bin", GIT_FILTER_TO_WORKTREE));
+		&fl, g_repo, NULL, "hero.bin", GIT_FILTER_TO_WORKTREE, 0));
 	/* expect: bitflip, reverse */
 	cl_assert_equal_sz(2, git_filter_list_length(fl));
 	git_filter_list_free(fl);
 
 	cl_git_pass(git_filter_list_load(
-		&fl, g_repo, NULL, "heroflip", GIT_FILTER_TO_WORKTREE));
+		&fl, g_repo, NULL, "heroflip", GIT_FILTER_TO_WORKTREE, 0));
 	/* expect: bitflip (because of -reverse) */
 	cl_assert_equal_sz(1, git_filter_list_length(fl));
 	git_filter_list_free(fl);
 
 	cl_git_pass(git_filter_list_load(
-		&fl, g_repo, NULL, "doesntapplytome.bin", GIT_FILTER_TO_WORKTREE));
+		&fl, g_repo, NULL, "doesntapplytome.bin",
+		GIT_FILTER_TO_WORKTREE, 0));
 	/* expect: none */
 	cl_assert_equal_sz(0, git_filter_list_length(fl));
 	git_filter_list_free(fl);
diff --git a/tests/filter/ident.c b/tests/filter/ident.c
index 2c8e6ab..2c9a3eb 100644
--- a/tests/filter/ident.c
+++ b/tests/filter/ident.c
@@ -39,7 +39,8 @@ void test_filter_ident__to_worktree(void)
 	git_filter_list *fl;
 	git_filter *ident;
 
-	cl_git_pass(git_filter_list_new(&fl, g_repo, GIT_FILTER_TO_WORKTREE));
+	cl_git_pass(git_filter_list_new(
+		&fl, g_repo, GIT_FILTER_TO_WORKTREE, 0));
 
 	ident = git_filter_lookup(GIT_FILTER_IDENT);
 	cl_assert(ident != NULL);
@@ -78,7 +79,8 @@ void test_filter_ident__to_odb(void)
 	git_filter_list *fl;
 	git_filter *ident;
 
-	cl_git_pass(git_filter_list_new(&fl, g_repo, GIT_FILTER_TO_ODB));
+	cl_git_pass(git_filter_list_new(
+		&fl, g_repo, GIT_FILTER_TO_ODB, 0));
 
 	ident = git_filter_lookup(GIT_FILTER_IDENT);
 	cl_assert(ident != NULL);
diff --git a/tests/object/blob/filter.c b/tests/object/blob/filter.c
index 0b2d6bf..9798055 100644
--- a/tests/object/blob/filter.c
+++ b/tests/object/blob/filter.c
@@ -121,7 +121,7 @@ void test_object_blob_filter__to_odb(void)
 	cl_git_append2file("empty_standard_repo/.gitattributes", "*.txt text\n");
 
 	cl_git_pass(git_filter_list_load(
-		&fl, g_repo, NULL, "filename.txt", GIT_FILTER_TO_ODB));
+		&fl, g_repo, NULL, "filename.txt", GIT_FILTER_TO_ODB, 0));
 	cl_assert(fl != NULL);
 
 	for (i = 0; i < CRLF_NUM_TEST_OBJECTS; i++) {