fix: write the prompt to STDOUT before readline() on Windows (#10534)

Author: michalsn

system/CLI/InputOutput.php

@@ -44,12 +44,16 @@ public function input(?string $prefix = null): string
         // readline() can't be tested.
         if ($this->readlineSupport && ENVIRONMENT !== 'testing') {
             // @codeCoverageIgnoreStart
-            // Libedit reports "EditLine wrapper" and mangles the markers, so only GNU readline gets them.
-            if ($prefix !== null && ! str_contains(readline_info('library_version'), 'EditLine')) {
-                $prefix = $this->markAnsiNonPrinting($prefix);
+            $prompt = $this->readlinePrompt($prefix, readline_info('library_version'));
+
+            if ($prompt !== null) {
+                return readline($prompt);
             }
 
-            return readline($prefix);
+            // The library cannot render the prompt, so write it ourselves and let readline() only read the line.
+            self::fwrite(STDOUT, $prefix ?? '');
+
+            return readline();
             // @codeCoverageIgnoreEnd
         }
 
@@ -86,6 +90,31 @@ public function fwrite($handle, string $string): void
         fwrite($handle, $string);
     }
 
+    /**
+     * Builds the prompt handed to readline(), or returns null when the caller has to write
+     * the prompt to STDOUT itself because the line-editing library cannot render it.
+     *
+     * GNU readline gets ANSI sequences wrapped in its non-printing markers so line-redraw
+     * column accounting skips them. Libedit reports "EditLine wrapper" and mangles the
+     * markers, so it gets the raw prompt. Windows builds use WinEditLine, which prints ANSI
+     * sequences literally, and readline_info() omits the version there (php-src guards it
+     * with #ifndef PHP_WIN32), so they get no prompt.
+     *
+     * @param mixed $libraryVersion The value of readline_info('library_version')
+     */
+    private function readlinePrompt(?string $prefix, mixed $libraryVersion): ?string
+    {
+        if ($prefix === null || ! is_string($libraryVersion)) {
+            return null;
+        }
+
+        if (str_contains($libraryVersion, 'EditLine')) {
+            return $prefix;
+        }
+
+        return $this->markAnsiNonPrinting($prefix);
+    }
+
     /**
      * Wraps ANSI escape sequences in readline's non-printing markers so line-redraw column accounting skips them.
      */

tests/system/CLI/CLITest.php

@@ -267,6 +267,43 @@ public function testMarkAnsiNonPrintingWrapsEscapeSequences(): void
         $this->assertSame('Name: ', $wrap('Name: '));
     }
 
+    #[DataProvider('provideReadlinePromptDependsOnLibrary')]
+    public function testReadlinePromptDependsOnLibrary(mixed $libraryVersion, ?string $expected): void
+    {
+        $build = $this->getPrivateMethodInvoker(new InputOutput(), 'readlinePrompt');
+
+        $this->assertSame(
+            $expected,
+            $build(sprintf('What is your favorite color?  [%s]: ', CLI::color('red', 'green')), $libraryVersion),
+        );
+    }
+
+    /**
+     * @return iterable<string, array{0: mixed, 1: string|null}>
+     */
+    public static function provideReadlinePromptDependsOnLibrary(): iterable
+    {
+        yield 'GNU readline gets the prompt with non-printing markers' => [
+            '8.2',
+            "What is your favorite color?  [\x01\e[0;32m\x02red\x01\e[0m\x02]: ",
+        ];
+
+        yield 'libedit gets the raw prompt' => [
+            'EditLine wrapper',
+            "What is your favorite color?  [\e[0;32mred\e[0m]: ",
+        ];
+
+        // Official Windows builds use WinEditLine, which exposes no library version.
+        yield 'WinEditLine gets no prompt so the caller writes it' => [null, null];
+    }
+
+    public function testReadlinePromptWithoutPrefixReturnsNull(): void
+    {
+        $build = $this->getPrivateMethodInvoker(new InputOutput(), 'readlinePrompt');
+
+        $this->assertNull($build(null, '8.2'));
+    }
+
     public function testPromptByKey(): void
     {
         PhpStreamWrapper::register();

user_guide_src/source/changelogs/v4.7.5.rst

@@ -38,6 +38,7 @@ Bugs Fixed
 
 - **CLI:** Fixed a bug where pressing backspace in a ``CLI::prompt()`` erased the prompt text when the ``readline`` extension is enabled. The prompt is now passed to ``readline()`` so line redraws repaint it.
   ANSI color codes in the prompt (e.g., option defaults) are wrapped in readline's non-printing markers under GNU readline so cursor positioning stays accurate.
+  On Windows, where the ``readline`` extension is built on WinEditLine, the prompt is written to STDOUT first because WinEditLine reports no library version and prints ANSI sequences literally.
 - **CLIRequest:** Fixed a bug where ``parseCommand()`` could throw a TypeError when ``argv`` is missing.
 - **CodeIgniter:** Fixed a bug where ``gatherOutput()`` could be called twice when ``startController()`` returned a ``ResponseInterface`` (e.g., from filter attributes or closure routes).
 - **Content Security Policy:** Fixed a bug where empty ``Content-Security-Policy``, ``Content-Security-Policy-Report-Only``, and ``Reporting-Endpoints`` response headers were generated when no corresponding values existed.