Added migration flag for users using old JSON format.

1 files changed, 11 insertions, 1 deletions

diff --git a/upb/json/parser.c b/upb/json/parser.c
index 3731478..e1a334d 100644
--- a/upb/json/parser.c
+++ b/upb/json/parser.c
@@ -1627,14 +1627,24 @@ static void add_jsonname_table(upb_json_parsermethod *m, const upb_msgdef* md) {
       !upb_msg_field_done(&i);
       upb_msg_field_next(&i)) {
     const upb_fielddef *f = upb_msg_iter_field(&i);
+
     size_t field_len = upb_fielddef_getjsonname(f, buf, len);
     if (field_len > len) {
+      size_t len2;
       buf = realloc(buf, field_len);
       len = field_len;
-      upb_fielddef_getjsonname(f, buf, len);
+      len2 = upb_fielddef_getjsonname(f, buf, len);
+      UPB_ASSERT_VAR(len2, len == len2);
     }
     upb_strtable_insert(t, buf, upb_value_constptr(f));
 
+    if (getenv("UPB_JSON_ACCEPT_LEGACY_FIELD_NAMES")) {
+      /* Temporary code to help people migrate if they were depending on the
+       * old, non-proto3-json-compliant field names.  In this case we
+       * recognize both old names and new names. */
+      upb_strtable_insert(t, upb_fielddef_name(f), upb_value_constptr(f));
+    }
+
     if (upb_fielddef_issubmsg(f)) {
       add_jsonname_table(m, upb_fielddef_msgsubdef(f));
     }