From ef24ae4e93cf8635ff38398b37f3597e5d478330 Mon Sep 17 00:00:00 2001
From: Alexander Fenster <fenster@google.com>
Date: Fri, 26 Aug 2022 12:56:02 -0700
Subject: [PATCH] feat: accept unknown enum values in fromObject (#1793)

* feat: accept unknown enum values in fromObject

* fix: lint
---
 src/converter.js        | 12 +++++++++---
 tests/api_converters.js |  7 ++++---
 2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/src/converter.js b/src/converter.js
index d0467dcd2..a043ceef8 100644
--- a/src/converter.js
+++ b/src/converter.js
@@ -23,8 +23,14 @@ function genValuePartial_fromObject(gen, field, fieldIndex, prop) {
         if (field.resolvedType instanceof Enum) { gen
             ("switch(d%s){", prop);
             for (var values = field.resolvedType.values, keys = Object.keys(values), i = 0; i < keys.length; ++i) {
-                if (field.repeated && values[keys[i]] === field.typeDefault) gen
-                ("default:");
+                // enum unknown values passthrough
+                if (values[keys[i]] === field.typeDefault) { gen
+                    ("default:")
+                        ("if(typeof(d%s)===\"number\"){m%s=d%s;break}", prop, prop, prop);
+                    if (!field.repeated) gen // fallback to default value only for
+                                             // arrays, to avoid leaving holes.
+                        ("break");           // for non-repeated fields, just ignore
+                }
                 gen
                 ("case%j:", keys[i])
                 ("case %i:", values[keys[i]])
@@ -156,7 +162,7 @@ function genValuePartial_toObject(gen, field, fieldIndex, prop) {
     /* eslint-disable no-unexpected-multiline, block-scoped-var, no-redeclare */
     if (field.resolvedType) {
         if (field.resolvedType instanceof Enum) gen
-            ("d%s=o.enums===String?types[%i].values[m%s]:m%s", prop, fieldIndex, prop, prop);
+            ("d%s=o.enums===String?(types[%i].values[m%s]===undefined?m%s:types[%i].values[m%s]):m%s", prop, fieldIndex, prop, prop, fieldIndex, prop, prop);
         else gen
             ("d%s=types[%i].toObject(m%s,o)", prop, fieldIndex, prop);
     } else {
diff --git a/tests/api_converters.js b/tests/api_converters.js
index ccfd68be6..0ad9010d1 100644
--- a/tests/api_converters.js
+++ b/tests/api_converters.js
@@ -103,7 +103,7 @@ tape.test("converters", function(test) {
                     bytesVal: buf,
                     bytesRepeated: [buf, buf],
                     enumVal: 2,
-                    enumRepeated: [1, 2],
+                    enumRepeated: [1, 100, 2],
                     int64Map: {
                         a: protobuf.util.Long.fromNumber(2),
                         b: protobuf.util.Long.fromNumber(3)
@@ -127,6 +127,7 @@ tape.test("converters", function(test) {
                     test.ok(Buffer.isBuffer(Message.toObject(msg, { bytes: Buffer }).bytesVal), "bytes to buffers");
 
                 test.equal(Message.toObject(msg, { enums: String }).enumVal, "TWO", "enums to strings");
+                test.equal(Message.toObject(msg, { enums: String }).enumRepeated[1], 100, "enums to strings does not change unknown values");
 
                 test.end();
             });
@@ -157,7 +158,7 @@ tape.test("converters", function(test) {
                 bytesVal: "MTEx",
                 bytesRepeated: ["MTEx", [49, 49, 49]],
                 enumVal: "ONE",
-                enumRepeated: [2, "TWO"],
+                enumRepeated: [2, "TWO", 100],
                 int64Map: {
                     a: 2,
                     b: "3"
@@ -176,7 +177,7 @@ tape.test("converters", function(test) {
             test.same(msg.bytesVal, buf, "should set bytesVal from a base64 string");
             test.same(msg.bytesRepeated, [ buf, buf ], "should set bytesRepeated from a base64 string and a plain array");
             test.equal(msg.enumVal, 1, "should set enumVal from a string");
-            test.same(msg.enumRepeated, [ 2, 2 ], "should set enumRepeated from a number and a string");
+            test.same(msg.enumRepeated, [ 2, 2, 100 ], "should set enumRepeated from a number and a string and preserve unknown value");
             test.same(msg.int64Map, { a: { low: 2, high: 0, unsigned: false }, b: { low: 3, high: 0, unsigned: false } }, "should set int64Map from a number and a string");
 
             test.end();