Fix ConnectionErrorProof response count on single node read errors (#1739)

Co-authored-by: Till Krüss <tillkruss@users.noreply.github.com>

CHANGELOG.md

@@ -9,13 +9,14 @@
 ### Fixed
 - Fixed client iteration with master/slave and Sentinel replication (#923)
 - Fixed `*StreamConnection` looping forever when closed in the middle of a bulk reply (#1731)
-- Fixed cluster CAS transactions returning transaction objects for reads and sending `MULTI` twice
-- Fixed `MultiExec::multi()` being ignored as the first call of a CAS transaction
-- Fixed cleanup of empty transactions and transaction callbacks that throw PHP errors
-- Fixed `spl_object_hash()` deprecation on PHP 8.6 in `ConnectionErrorProof` pipeline
+- Fixed cluster CAS transactions returning transaction objects for reads and sending `MULTI` twice (#1735)
+- Fixed `MultiExec::multi()` being ignored as the first call of a CAS transaction (#1735)
+- Fixed cleanup of empty transactions and transaction callbacks that throw PHP errors (#1735)
+- Fixed `spl_object_hash()` deprecation on PHP 8.6 in `ConnectionErrorProof` pipeline (#1738)
+- Fixed `ConnectionErrorProof` pipeline returning too few responses or throwing `ValueError` (#1739)
 
 ### Security
-- Fixed aborted cluster transactions leaving node connections in `MULTI`
+- Fixed aborted cluster transactions leaving node connections in `MULTI` (#1735)
 
 ## v3.6.1 (2026-09-17)
 ### Fixed

src/Pipeline/ConnectionErrorProof.php

@@ -73,7 +73,7 @@ class ConnectionErrorProof extends Pipeline
             try {
                 $responses[$i] = $connection->readResponse($command);
             } catch (CommunicationException $exception) {
-                $add = count($commands) - count($responses);
+                $add = $sizeOfPipe - count($responses);
                 $responses = array_merge($responses, array_fill(0, $add, $exception));
 
                 break;

tests/Predis/Pipeline/ConnectionErrorProofTest.php

@@ -138,6 +138,62 @@ class ConnectionErrorProofTest extends PredisTestCase
         $pipeline->execute();
     }
 
+    /**
+     * @dataProvider singleConnectionReadFailureProvider
+     * @group disconnected
+     */
+    public function testReturnsExceptionForFailedAndRemainingCommandsOnReadFailureWithSingleConnection(
+        int $sizeOfPipe,
+        int $failingIndex
+    ): void {
+        $connection = $this->getMockConnection('tcp://127.0.0.1:7001');
+        $exception = new ConnectionException($connection, 'Connection lost');
+
+        $readResponses = [];
+        $expectedResponses = [];
+
+        for ($i = 0; $i < $sizeOfPipe; ++$i) {
+            if ($i < $failingIndex) {
+                $readResponses[] = "value$i";
+                $expectedResponses[] = "value$i";
+            } else {
+                $expectedResponses[] = $exception;
+            }
+        }
+
+        $readResponses[] = $this->throwException($exception);
+
+        $connection
+            ->expects($this->once())
+            ->method('write');
+        $connection
+            ->expects($this->exactly($failingIndex + 1))
+            ->method('readResponse')
+            ->willReturnOnConsecutiveCalls(...$readResponses);
+
+        $pipeline = new ConnectionErrorProof(new Client($connection));
+
+        for ($i = 0; $i < $sizeOfPipe; ++$i) {
+            $pipeline->echo("value$i");
+        }
+
+        $responses = $pipeline->execute();
+
+        $this->assertCount($sizeOfPipe, $responses);
+        $this->assertSame($expectedResponses, $responses);
+    }
+
+    public function singleConnectionReadFailureProvider(): array
+    {
+        return [
+            'single command' => [1, 0],
+            'first of three' => [3, 0],
+            'second of three' => [3, 1],
+            'last of three' => [3, 2],
+            'fourth of five' => [5, 3],
+        ];
+    }
+
     /**
      * Returns a mocked cluster connection routing commands by their first key.
      *