Add filter options and ALLOW_UNSAFE

Diff and status do not want core.safecrlf to actually raise an
error regardless of the setting, so this extends the filter API
with an additional options flags parameter and adds a flag so that
filters can be applied with GIT_FILTER_OPT_ALLOW_UNSAFE, indicating
that unsafe filter application should be downgraded from a failure
to a warning.

7 files changed, 46 insertions, 12 deletions

diff --git a/src/blob.c b/src/blob.c
index 0aa2516db..ab7dec67f 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 b869efe2b..20763fd35 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 8be1b9a05..dad3ecebc 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 781f23ec6..bc23e6b0d 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 b9f92df3f..f2a1d5099 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 b2f57964a..b0e2b8bea 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 ac7af7692..df5f322ce 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 {