diff: include oid length in deltas

Now that `git_diff_delta` data can be produced by reading patch
file data, which may have an abbreviated oid, allow consumers to
know that the id is abbreviated.

4 files changed, 37 insertions, 8 deletions

diff --git a/src/diff.c b/src/diff.c
index 26c0b895b..9c27511f6 100644
--- a/src/diff.c
+++ b/src/diff.c
@@ -151,11 +151,13 @@ static int diff_delta__from_one(
 		delta->old_file.size = entry->file_size;
 		delta->old_file.flags |= GIT_DIFF_FLAG_EXISTS;
 		git_oid_cpy(&delta->old_file.id, &entry->id);
+		delta->old_file.id_abbrev = GIT_OID_HEXSZ;
 	} else /* ADDED, IGNORED, UNTRACKED */ {
 		delta->new_file.mode = entry->mode;
 		delta->new_file.size = entry->file_size;
 		delta->new_file.flags |= GIT_DIFF_FLAG_EXISTS;
 		git_oid_cpy(&delta->new_file.id, &entry->id);
+		delta->new_file.id_abbrev = GIT_OID_HEXSZ;
 	}
 
 	delta->old_file.flags |= GIT_DIFF_FLAG_VALID_ID;
@@ -208,12 +210,14 @@ static int diff_delta__from_two(
 		delta->old_file.size = old_entry->file_size;
 		delta->old_file.mode = old_mode;
 		git_oid_cpy(&delta->old_file.id, old_id);
+		delta->old_file.id_abbrev = GIT_OID_HEXSZ;
 		delta->old_file.flags |= GIT_DIFF_FLAG_VALID_ID |
 			GIT_DIFF_FLAG_EXISTS;
 	}
 
 	if (!git_index_entry_is_conflict(new_entry)) {
 		git_oid_cpy(&delta->new_file.id, new_id);
+		delta->new_file.id_abbrev = GIT_OID_HEXSZ;
 		delta->new_file.size = new_entry->file_size;
 		delta->new_file.mode = new_mode;
 		delta->old_file.flags |= GIT_DIFF_FLAG_EXISTS;
diff --git a/src/diff_file.c b/src/diff_file.c
index ecc34cf55..8b945a5b7 100644
--- a/src/diff_file.c
+++ b/src/diff_file.c
@@ -149,12 +149,14 @@ int git_diff_file_content__init_from_src(
 		if (src->blob) {
 			fc->file->size = git_blob_rawsize(src->blob);
 			git_oid_cpy(&fc->file->id, git_blob_id(src->blob));
+			fc->file->id_abbrev = GIT_OID_HEXSZ;
 
 			fc->map.len  = (size_t)fc->file->size;
 			fc->map.data = (char *)git_blob_rawcontent(src->blob);
 		} else {
 			fc->file->size = src->buflen;
 			git_odb_hash(&fc->file->id, src->buf, src->buflen, GIT_OBJ_BLOB);
+			fc->file->id_abbrev = GIT_OID_HEXSZ;
 
 			fc->map.len  = src->buflen;
 			fc->map.data = (char *)src->buf;
diff --git a/src/diff_print.c b/src/diff_print.c
index 09bf77aef..7c9af2449 100644
--- a/src/diff_print.c
+++ b/src/diff_print.c
@@ -208,6 +208,7 @@ static int diff_print_one_raw(
 {
 	diff_print_info *pi = data;
 	git_buf *out = pi->buf;
+	int id_abbrev;
 	char code = git_diff_status_char(delta->status);
 	char start_oid[GIT_OID_HEXSZ+1], end_oid[GIT_OID_HEXSZ+1];
 
@@ -218,6 +219,16 @@ static int diff_print_one_raw(
 
 	git_buf_clear(out);
 
+	id_abbrev = delta->old_file.mode ? delta->old_file.id_abbrev :
+		delta->new_file.id_abbrev;
+
+	if (pi->oid_strlen - 1 > id_abbrev) {
+		giterr_set(GITERR_PATCH,
+			"The patch input contains %d id characters (cannot print %d)",
+			id_abbrev, pi->oid_strlen);
+		return -1;
+	}
+
 	git_oid_tostr(start_oid, pi->oid_strlen, &delta->old_file.id);
 	git_oid_tostr(end_oid, pi->oid_strlen, &delta->new_file.id);
 
@@ -252,6 +263,22 @@ static int diff_print_oid_range(
 {
 	char start_oid[GIT_OID_HEXSZ+1], end_oid[GIT_OID_HEXSZ+1];
 
+	if (delta->old_file.mode &&
+			oid_strlen - 1 > delta->old_file.id_abbrev) {
+		giterr_set(GITERR_PATCH,
+			"The patch input contains %d id characters (cannot print %d)",
+			delta->old_file.id_abbrev, oid_strlen);
+		return -1;
+	}
+
+	if ((delta->new_file.mode &&
+			oid_strlen - 1 > delta->new_file.id_abbrev)) {
+		giterr_set(GITERR_PATCH,
+			"The patch input contains %d id characters (cannot print %d)",
+			delta->new_file.id_abbrev, oid_strlen);
+		return -1;
+	}
+
 	git_oid_tostr(start_oid, oid_strlen, &delta->old_file.id);
 	git_oid_tostr(end_oid, oid_strlen, &delta->new_file.id);
 
diff --git a/src/patch_parse.c b/src/patch_parse.c
index 11e26936c..323f8dc95 100644
--- a/src/patch_parse.c
+++ b/src/patch_parse.c
@@ -197,15 +197,11 @@ static int parse_header_oid(
 static int parse_header_git_index(
 	git_patch_parsed *patch, patch_parse_ctx *ctx)
 {
-	/*
-	* TODO: we read the prefix provided in the diff into the delta's id
-	* field, but do not mark is at an abbreviated id.
-	*/
-	size_t oid_len, nid_len;
-
-	if (parse_header_oid(&patch->base.delta->old_file.id, &oid_len, ctx) < 0 ||
+	if (parse_header_oid(&patch->base.delta->old_file.id,
+			&patch->base.delta->old_file.id_abbrev, ctx) < 0 ||
 		parse_advance_expected(ctx, "..", 2) < 0 ||
-		parse_header_oid(&patch->base.delta->new_file.id, &nid_len, ctx) < 0)
+		parse_header_oid(&patch->base.delta->new_file.id,
+			&patch->base.delta->new_file.id_abbrev, ctx) < 0)
 		return -1;
 
 	if (ctx->line_len > 0 && ctx->line[0] == ' ') {