🥅 Catch json0 normalization errors

We have some alerts in production that are resulting from uncaught
errors originating from `normalizeJson0Paths()`.

This change catches these errors, and wraps them in a `ShareDBError` so
that we can try to get more context to analyse with the error.

Author: alecgibson

lib/error.js

@@ -38,6 +38,7 @@ ShareDBError.CODES = {
   ERR_OP_VERSION_MISMATCH_AFTER_TRANSFORM: 'ERR_OP_VERSION_MISMATCH_AFTER_TRANSFORM',
   ERR_OP_VERSION_MISMATCH_DURING_TRANSFORM: 'ERR_OP_VERSION_MISMATCH_DURING_TRANSFORM',
   ERR_OP_VERSION_NEWER_THAN_CURRENT_SNAPSHOT: 'ERR_OP_VERSION_NEWER_THAN_CURRENT_SNAPSHOT',
+  ERR_OT_LEGACY_JSON0_OP_CANNOT_BE_NORMALIZED: 'ERR_OT_LEGACY_JSON0_OP_CANNOT_BE_NORMALIZED',
   ERR_OT_OP_BADLY_FORMED: 'ERR_OT_OP_BADLY_FORMED',
   ERR_OT_OP_NOT_APPLIED: 'ERR_OT_OP_NOT_APPLIED',
   ERR_OT_OP_NOT_PROVIDED: 'ERR_OT_OP_NOT_PROVIDED',

lib/ot.js

@@ -164,7 +164,16 @@ exports.applyOps = function(snapshot, ops, options) {
   options = options || {};
   for (var index = 0; index < ops.length; index++) {
     var op = ops[index];
-    if (options._normalizeLegacyJson0Ops) normalizeLegacyJson0Ops(snapshot, op);
+    if (options._normalizeLegacyJson0Ops) {
+      try {
+        normalizeLegacyJson0Ops(snapshot, op);
+      } catch (error) {
+        return new ShareDBError(
+          ERROR_CODE.ERR_OT_LEGACY_JSON0_OP_CANNOT_BE_NORMALIZED,
+          'Cannot normalize legacy json0 op'
+        );
+      }
+    }
     snapshot.v = op.v;
     var error = exports.apply(snapshot, op);
     if (error) return error;