Fixes: wordpress-mobile/WordPress-iOS#20882

Gutenberg Mobile PR: wordpress-mobile/gutenberg-mobile#6729

What?

This PR prevents a react-native-video-related crash that happens when an src changes quickly after first being set in the Video block.

Why?

As per wordpress-mobile/WordPress-iOS#20882, the crash impacts iOS users. Though the crash can't be reproduced consistently, it disrupts an important flow (uploading video) for those that do encounter it.

How?

A video may still have the file: protocol for a short time after it's uploaded. In those cases the showVideo const will currently return true and the src will be set. Shortly after, the src will be set again with the video's actual URL. It is likely this quick change to the src is causing the crash, as per the description of the react-native-video bug here.

With the above in mind, a check for the file: protocol has been added to showVideo in 8cf9fd4. Now, the src will not be changed quickly after it's first been set.

A similar guard was added for video code in the Jetpack app, which resolved the crash in that instance and adds weight to the idea that the proposed solution here will work as intended.

The change should not have a noticeable impact on the time it takes for a video's thumbnail to be displayed, as the file: protocol should only be in use for a very short time after the video has finished uploading (and we do not attempt to display the thumbnail while a video's uploading).

Testing Instructions

The crash has been difficult to reproduce. However, we can verify that the changes don't contribute to a delay in the video's thumbnail displaying and that the src is not changed rapidly when first set.

1. In the WordPress iOS app, navigate to a self-hosted site without Jetpack-connected.
2. Navigate to the post editor and add a video block.
3. Upload a video to the block and verify everything loads as expected, with no change to the amount of time the thumbnail takes to display.

If testing locally, you can use the following diff to log changes to the showVideo and src variables:

diff --git a/packages/block-library/src/video/edit.native.js b/packages/block-library/src/video/edit.native.js
index f6960f0888..6bcbe246af 100644
--- a/packages/block-library/src/video/edit.native.js
+++ b/packages/block-library/src/video/edit.native.js
@@ -294,6 +294,9 @@ class VideoEdit extends Component {
 								! isUploadInProgress &&
 								! isUploadFailed;
 
+							console.log( '1. Show Video: ', showVideo );
+							console.log( '2. src: ', src );
+
 							const icon = this.getIcon(
 								isUploadFailed
 									? ICON_TYPE.RETRY

Screenshots or screencast

These side-by-side videos demonstrate that there isn't a noticeable delay in the video's thumbnail being shown. (I promise they're different videos, you can tell by the placement of the cursor 😂)