[console] Ignore warning preambles before structured JSON

Author: coisa

src/Console/Logger/Processor/CommandOutputProcessor.php

@@ -108,9 +108,55 @@ private function decodeStructuredOutput(string $content): mixed
             return $decodedDocuments;
         }
 
+        $decodedStructuredOutput = $this->decodeStructuredOutputAfterTextPreamble($content);
+
+        if (null !== $decodedStructuredOutput) {
+            return $decodedStructuredOutput;
+        }
+
         return $content;
     }
 
+    /**
+     * Decodes structured output that is preceded by plain-text warnings or banners.
+     *
+     * Some tooling emits advisory text before a valid JSON payload even when a
+     * machine-readable format is requested. When the suffix starting at the
+     * first valid JSON token is fully decodable, the textual preamble SHALL be
+     * ignored so parent command envelopes remain parseable.
+     *
+     * @param string $content the buffered output contents
+     *
+     * @return mixed the decoded JSON payload when a valid structured suffix exists
+     */
+    private function decodeStructuredOutputAfterTextPreamble(string $content): mixed
+    {
+        $offset = 0;
+
+        while (null !== ($offset = $this->findNextJsonDocumentOffset($content, $offset))) {
+            $structuredSuffix = trim(substr($content, $offset));
+
+            if ('' === $structuredSuffix) {
+                return null;
+            }
+
+            try {
+                return $this->normalizeStructuredPayload(json_decode($structuredSuffix, true));
+            } catch (JsonException) {
+            }
+
+            $decodedDocuments = $this->decodeJsonDocumentStream($structuredSuffix);
+
+            if (null !== $decodedDocuments) {
+                return $decodedDocuments;
+            }
+
+            ++$offset;
+        }
+
+        return null;
+    }
+
     /**
      * Decodes a stream that contains multiple JSON documents separated by whitespace.
      *
@@ -220,6 +266,27 @@ private function consumeJsonDocument(string $content, int &$offset): ?string
         return null;
     }
 
+    /**
+     * Finds the offset of the next possible JSON document opening token.
+     *
+     * @param string $content the buffered output contents
+     * @param int $offset the offset from which scanning SHALL start
+     *
+     * @return ?int the offset of the next "{" or "[" token
+     */
+    private function findNextJsonDocumentOffset(string $content, int $offset): ?int
+    {
+        $length = \strlen($content);
+
+        for (; $offset < $length; ++$offset) {
+            if ('{' === $content[$offset] || '[' === $content[$offset]) {
+                return $offset;
+            }
+        }
+
+        return null;
+    }
+
     /**
      * Normalizes decoded structured payloads produced by wrapped tooling.
      *

tests/Console/Logger/Processor/CommandOutputProcessorTest.php

@@ -158,6 +158,38 @@ public function processWillDecodeMultipleJsonBufferedOutputsIntoAList(): void
         ], $context['output']);
     }
 
+    /**
+     * @return void
+     */
+    #[Test]
+    public function processWillDiscardPlainTextPreambleBeforeStructuredJsonOutput(): void
+    {
+        $processor = new CommandOutputProcessor();
+        $output = new BufferedOutput();
+        $output->write(
+            "Warning: advisory text before JSON.\n"
+            . "{\"about\":\"PHP CS Fixer\"}\n"
+            . "{\"totals\":{\"changed_files\":0,\"errors\":0},\"changed_files\":[\"src/Foo.php\"]}\n"
+        );
+
+        $context = $processor->process([
+            'output' => $output,
+        ]);
+
+        self::assertSame([
+            [
+                'about' => 'PHP CS Fixer',
+            ],
+            [
+                'totals' => [
+                    'changed_files' => 0,
+                    'errors' => 0,
+                ],
+                'changed_files' => [],
+            ],
+        ], $context['output']);
+    }
+
     /**
      * @return void
      */