From c5c8ffab79777e1587f8a6075676bd3404544f82 Mon Sep 17 00:00:00 2001
From: Protobuf Team Bot <protobuf-github-bot@google.com>
Date: Sun, 30 Aug 2026 06:43:10 -0700
Subject: [PATCH] Emit `null` when serializing unset Google\Protobuf\Value to
 JSON in pure-PHP runtime.

Note that this won't perfectly round trip, since on parse-back the `null_value` arm will be set instead, but the common behavior of other impls is to emit `null` for this.

Before this fix, the Pure-PHP JSON implementation would emit malformed JSON by emitting no value,, like `{"someValueField": }`

Note that this actually won't perfectly round-trip (since the parse-back will parse it as a Value with null_value kind). This matches the behavior of our other runtimes.

PiperOrigin-RevId: 973442012
---
 php/src/Google/Protobuf/Internal/Message.php | 23 ++++++++++++++++++++
 php/tests/EncodeDecodeTest.php               | 23 ++++++++++++++++++++
 2 files changed, 46 insertions(+)

diff --git a/php/src/Google/Protobuf/Internal/Message.php b/php/src/Google/Protobuf/Internal/Message.php
index 348e8658c61e5..c3e0513d29600 100644
--- a/php/src/Google/Protobuf/Internal/Message.php
+++ b/php/src/Google/Protobuf/Internal/Message.php
@@ -1540,6 +1540,19 @@ public function serializeToJsonStream(&$output)
                     return false;
                 }
             }
+        } elseif (is_a($this, 'Google\Protobuf\Value')) {
+            $field = $this->desc->getFieldByName($this->getKind());
+            if (!$field) {
+                // A Value with no case of the oneof set is documented as 'invalid',
+                // but is trivially constructable and representable in binary format.
+                // Handle this as though `null_value` was set.
+                $output->writeRaw("null", 4);
+                return true;
+            } else {
+                if (!$this->serializeFieldToJsonStream($output, $field)) {
+                    return false;
+                }
+            }
         } else {
             if (!GPBUtil::hasSpecialJsonMapping($this)) {
                 $output->writeRaw("{", 1);
@@ -2066,6 +2079,16 @@ public function jsonByteSize($options = 0)
                 // Size for "{}".
                 $size += 2;
             }
+        } elseif (is_a($this, 'Google\Protobuf\Value')) {
+            $field = $this->desc->getFieldByName($this->getKind());
+            if (!$field) {
+                // A Value with no case of the oneof set is documented as
+                // 'invalid', but is trivially constructable and representable
+                // in binary format. Handle this as though `null_value` was set.
+                $size += 4;
+            } else {
+                $size += $this->fieldJsonByteSize($field, $options);
+            }
         } else {
             if (!GPBUtil::hasSpecialJsonMapping($this)) {
                 // Size for "{}".
diff --git a/php/tests/EncodeDecodeTest.php b/php/tests/EncodeDecodeTest.php
index 71a6bc1533e31..31136004945f5 100644
--- a/php/tests/EncodeDecodeTest.php
+++ b/php/tests/EncodeDecodeTest.php
@@ -1159,6 +1159,9 @@ public function testDecodeTopLevelValue()
 
     public function testEncodeTopLevelValue()
     {
+        $m = new Value();
+        $this->assertSame("null", $m->serializeToJsonString());
+
         $m = new Value();
         $m->setStringValue("a");
         $this->assertSame("\"a\"", $m->serializeToJsonString());
@@ -1176,6 +1179,26 @@ public function testEncodeTopLevelValue()
         $this->assertSame("null", $m->serializeToJsonString());
     }
 
+    public function testEncodeUnsetValue()
+    {
+        $m = new Struct();
+        $m->setFields(['k' => new Value()]);
+        $this->assertSame('{"k":null}', $m->serializeToJsonString());
+
+        $m = new ListValue();
+        $m->setValues([new Value(), new Value()]);
+        $this->assertSame('[null,null]', $m->serializeToJsonString());
+
+        // Unset Value decoded from 0-length sub-message wire bytes.
+        $m = new Struct();
+        $m->mergeFromString(hex2bin("0a050a016b1200"));
+        $this->assertSame('{"k":null}', $m->serializeToJsonString());
+
+        $m = new ListValue();
+        $m->mergeFromString(hex2bin("0a000a00"));
+        $this->assertSame('[null,null]', $m->serializeToJsonString());
+    }
+
     public function testDecodeTopLevelListValue()
     {
         $m = new ListValue();