Capacitor speech plugin bug: @capacitor-community/speech-recognition 7.0.1 fails every other press

The app in question is a self-made travel English shadowing tool that records the user's speech, converts it to text via speech recognition, and scores the match against a model sentence. On PC it used the browser's Web Speech API, but when wrapped as an Android app with Capacitor, the team chose to always use the native Android speech recognizer because Android's WebView exposes webkitSpeechRecognition as present while it does not actually function (Chromium issue 41172064). That decision set the stage for the bug, which lived in the native plugin layer.

The debugging was done by Claude Code, which first read the plugin's Android source and suspected the destroy-and-recreate pattern, but then connected a real device and measured before changing anything. Using adb to attach to the WebView's debug port, it wrapped Capacitor's native call bridge to log per-call response times, and simultaneously captured device logs with adb logcat. The logs showed that 4 ms after start, an error was already being sent, followed by the microphone opening and listening for 5 seconds before ending with "no speech detected"—and the same call received error notifications three times. The plugin's getErrorText() maps unrecognized error codes to the default "Didn't understand, please try again." message, so the exact code was not visible in the pre-fix version.

The patch makes three changes: it creates the SpeechRecognizer only if none exists and otherwise just cancels the previous session; it nulls out the call reference in onError() so the same call is not rejected twice; and it does the same single-settlement in onResults(). One caveat noted is that Android's official documentation says the caller must invoke destroy() when a SpeechRecognizer is no longer needed, and this patch simply stops calling destroy() on each press—the plugin has no other place that calls it. A practical snag during patching on Windows was a "Filename too long" error from npx patch-package, which was resolved by deleting the android/build folder before regenerating the patch.