Reporting bugs in WebView

Thanks for your interest in reporting a bug with Android WebView! We have some tips and guidelines for how you can file your bug report to help us quickly diagnose your bug.

You can file WebView bugs at https://issues.chromium.org/issues/new?component=1456456&template=1923373, but please continue reading to understand the best practices for reporting WebView bugs.

Reproducible in Google Chrome browser

If a bug can reproduce in Google Chrome browser, it's best to file this as a Chrome bug, not as a WebView bug. This is true even if the bug also reproduces in both Chrome and WebView. Please file this at https://crbug.com/wizard so that the Chrome team can properly triage this.

Capture a bug report zip file

It's ideal if you can capture a bug report zip file on the repro device right after you reproduce the bug. See Capture and read bug reports for instructions on how to automatically generate this zip file on Android. Please attach the zip file when you file your bug.

This zip file includes the standard set of device logs (also known as adb logcat), but it also includes several other debug information which is useful for diagnosing the issue.

Highlight WebViews

There‘s a debug flag you can turn on which will highlight all WebViews with a yellow color. This is useful for bug reports because it helps us confirm if WebView is the culprit or if it’s a different web technology which is causing the bug.

You can enable this with 3 steps:

1. Launch WebView DevTools. The easiest way of doing this is with an adb command:

   adb shell am start -a "com.android.webview.SHOW_DEV_UI"
   

   If you don‘t have adb installed or can’t use it for some reason, then consult WebView DevTools user guide for other ways to launch.

2. Tap the “Flags” option in the bottom navigation bar. Select highlight-all-webviews and toggle this to Enabled.

3. Kill your other apps and restart them. They will now highlight all WebViews in yellow.

To undo this, swipe down from the top of your screen to find a notification from WebView DevTools. You can tap this notification to be taken back to WebView DevTools where you can tap the Reset flags button at the top of the screen.

Record a video

If you can reproduce the bug, then please try to record a video showing the repro steps. Here's the quick steps for doing this:

1. Please enable highlight-all-webviews so we can clearly see where the WebViews are when you repro the bug (see the previous section for instructions).
2. Newer Android versions have a builtin screen record option. To use this option, swipe down twice from the top of your screen.
3. Tap the Screen record button. You might need to swipe right to find this button. If you cannot find the option, then please see Take a screenshot or record your screen on your Android device for full instructions.
4. Choose what you want to record, enable the show touches option, and tap Start.
5. When you're done reproducing the issue, swipe down again from the top of the screen and tap the Screen recorder notification to stop recording.
6. Attach the mp4 video file when you file your bug report.

Alternative instructions: If you cannot find the screen record option, then you can use the adb commandline tool instead:

1. Enable developer options. The usual way to do this is go into Settings > About phone > Build number > tap the Build Number seven times until you see the message “You are now a developer!”
2. Return to the previous screen in the settings app to find Developer options at the bottom.
3. Scroll through developer options until you find the Input section. Turn on the Show taps option.
4. Connect your device to your computer with a USB cable. Record a video with adb shell screenrecord /sdcard/demo.mp4. Start reproducing the bug on your device. Press Control + C to stop recording when you're done. Run adb pull /sdcard/demo.mp4 to pull the video file to your computer.
5. Attach the mp4 video file when you file your bug report.

Create a minimal sample app

If you can create a minimal sample app to reproduce the bug, this is usually very helpful at resolving your issue quickly. To help us work quickly, we need two files from you:

1. A compiled APK file, and
2. A zip file of source code (.zip format is preferred, please don't use 7zip or other archive formats)

Please attach both files to the bug report.

Tip: if your bug also reproduces on a real app, please mention this in the bug report as well. A sample app is still helpful, but knowing that this affects real apps will help us prioritize your report appropriately.

Reproducing bugs which require signing into app accounts

If a bug occurs in apps which require signing into an account, then you will either need to provide a minimal sample app which does not require sign-in credentials, or you will need to share a test account for us to reproduce with. The minimal sample app is always preferred.

If you decide to share sign-in credentials, then please let us know on the bug before you share the credentials. To share credentials, you can either attach this in Google Doc and share the link on the bug (members of our team will request access with our @google.com accounts) or you can ask us to restrict the entire bug to limited visibility + Google so that you can share the username/password in a bug comment. Please wait to share username/password until a member of our team has confirmed the bug is restricted.