fix(Spanner): ensure tag is passed to BeginTransactionRequest (#8935)

Author: bshaffer

Spanner/src/Transaction.php

@@ -444,12 +444,14 @@ public function commit(array $options = []): Timestamp
                 'requestOptions' => $this->requestOptions,
                 'transactionOptions' => $this->transactionOptions,
                 'singleUse' => $this->transactionSelector['singleUse'] ?? null,
+                'tag' => $this->tag ?? null,
             ]);
             if (!empty($mutations)) {
                 // Set the mutation key if we have mutations but do not have a precommit token
                 $mutationKey = $mutations[array_rand($mutations)];
                 $operationTransactionOptions['mutationKey'] = $mutationKey;
             }
+
             // Execute the beginTransaction RPC.
             $transaction = $this->operation->transaction($this->session, $operationTransactionOptions);
             // Set the transaction ID of the current transaction.

Spanner/tests/Unit/DatabaseTest.php

@@ -921,6 +921,32 @@ public function testRunTransactionAborted()
         });
     }
 
+    public function testRunTransactionWithTagOption()
+    {
+        $this->spannerClient->beginTransaction(
+            Argument::that(function (BeginTransactionRequest $request) {
+                $reqOptions = $request->getRequestOptions();
+                $this->assertNotNull($reqOptions);
+                $this->assertEquals(self::TRANSACTION_TAG, $reqOptions->getTransactionTag());
+                return true;
+            }),
+            Argument::type('array')
+        )
+            ->shouldBeCalledOnce()
+            ->willReturn(new TransactionProto(['id' => self::TRANSACTION]));
+
+        $this->spannerClient->commit(
+            Argument::type(CommitRequest::class),
+            Argument::type('array')
+        )
+            ->shouldBeCalled()
+            ->willReturn($this->commitResponse());
+
+        $this->database->runTransaction(function (Transaction $t) {
+            $t->commit();
+        }, ['tag' => self::TRANSACTION_TAG]);
+    }
+
     public function testTransaction()
     {
         $this->spannerClient->beginTransaction(