fsck: handle bad trees like other errors

Instead of dying when fsck hits a malformed tree object, log the error
like any other and continue.  Now fsck can tell the user which tree is
bad, too.

Signed-off-by: David Turner <dturner@twosigma.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 72 insertions, 11 deletions

diff --git a/tree-walk.c b/tree-walk.c
index 24f9a0f14..828f4356b 100644
--- a/tree-walk.c
+++ b/tree-walk.c
@@ -22,33 +22,60 @@ static const char *get_mode(const char *str, unsigned int *modep)
 	return str;
 }
 
-static void decode_tree_entry(struct tree_desc *desc, const char *buf, unsigned long size)
+static int decode_tree_entry(struct tree_desc *desc, const char *buf, unsigned long size, struct strbuf *err)
 {
 	const char *path;
 	unsigned int mode, len;
 
-	if (size < 23 || buf[size - 21])
-		die(_("too-short tree object"));
+	if (size < 23 || buf[size - 21]) {
+		strbuf_addstr(err, _("too-short tree object"));
+		return -1;
+	}
 
 	path = get_mode(buf, &mode);
-	if (!path)
-		die(_("malformed mode in tree entry for tree"));
-	if (!*path)
-		die(_("empty filename in tree entry for tree"));
+	if (!path) {
+		strbuf_addstr(err, _("malformed mode in tree entry"));
+		return -1;
+	}
+	if (!*path) {
+		strbuf_addstr(err, _("empty filename in tree entry"));
+		return -1;
+	}
 	len = strlen(path) + 1;
 
 	/* Initialize the descriptor entry */
 	desc->entry.path = path;
 	desc->entry.mode = canon_mode(mode);
 	desc->entry.oid  = (const struct object_id *)(path + len);
+
+	return 0;
 }
 
-void init_tree_desc(struct tree_desc *desc, const void *buffer, unsigned long size)
+static int init_tree_desc_internal(struct tree_desc *desc, const void *buffer, unsigned long size, struct strbuf *err)
 {
 	desc->buffer = buffer;
 	desc->size = size;
 	if (size)
-		decode_tree_entry(desc, buffer, size);
+		return decode_tree_entry(desc, buffer, size, err);
+	return 0;
+}
+
+void init_tree_desc(struct tree_desc *desc, const void *buffer, unsigned long size)
+{
+	struct strbuf err = STRBUF_INIT;
+	if (init_tree_desc_internal(desc, buffer, size, &err))
+		die("%s", err.buf);
+	strbuf_release(&err);
+}
+
+int init_tree_desc_gently(struct tree_desc *desc, const void *buffer, unsigned long size)
+{
+	struct strbuf err = STRBUF_INIT;
+	int result = init_tree_desc_internal(desc, buffer, size, &err);
+	if (result)
+		error("%s", err.buf);
+	strbuf_release(&err);
+	return result;
 }
 
 void *fill_tree_descriptor(struct tree_desc *desc, const unsigned char *sha1)
@@ -75,7 +102,7 @@ static void entry_extract(struct tree_desc *t, struct name_entry *a)
 	*a = t->entry;
 }
 
-void update_tree_entry(struct tree_desc *desc)
+static int update_tree_entry_internal(struct tree_desc *desc, struct strbuf *err)
 {
 	const void *buf = desc->buffer;
 	const unsigned char *end = desc->entry.oid->hash + 20;
@@ -89,7 +116,30 @@ void update_tree_entry(struct tree_desc *desc)
 	desc->buffer = buf;
 	desc->size = size;
 	if (size)
-		decode_tree_entry(desc, buf, size);
+		return decode_tree_entry(desc, buf, size, err);
+	return 0;
+}
+
+void update_tree_entry(struct tree_desc *desc)
+{
+	struct strbuf err = STRBUF_INIT;
+	if (update_tree_entry_internal(desc, &err))
+		die("%s", err.buf);
+	strbuf_release(&err);
+}
+
+int update_tree_entry_gently(struct tree_desc *desc)
+{
+	struct strbuf err = STRBUF_INIT;
+	if (update_tree_entry_internal(desc, &err)) {
+		error("%s", err.buf);
+		strbuf_release(&err);
+		/* Stop processing this tree after error */
+		desc->size = 0;
+		return -1;
+	}
+	strbuf_release(&err);
+	return 0;
 }
 
 int tree_entry(struct tree_desc *desc, struct name_entry *entry)
@@ -102,6 +152,17 @@ int tree_entry(struct tree_desc *desc, struct name_entry *entry)
 	return 1;
 }
 
+int tree_entry_gently(struct tree_desc *desc, struct name_entry *entry)
+{
+	if (!desc->size)
+		return 0;
+
+	*entry = desc->entry;
+	if (update_tree_entry_gently(desc))
+		return 0;
+	return 1;
+}
+
 void setup_traverse_info(struct traverse_info *info, const char *base)
 {
 	int pathlen = strlen(base);