[HOLD for PR #18997] Chat - Infinite loading after opening attached image a few times

[lanitochka17]

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Action Performed:

1. Open the app
2. Open any chat
3. Tap the "+" button and select "Add attachment" > "Choose from gallery"
4. Select any image and tap "Send"
5. Open the image and close it a few times

Expected Result:

The image preview is shown every time

Actual Result:

Infinite loading after opening the image preview a few times. The same behavior when opening images from old chats

Workaround:

Unknown

Platforms:

Which of our officially supported platforms is this issue occurring on?

• Android / native
• Android / Chrome
• iOS / native
• iOS / Safari
• MacOS / Chrome / Safari
• MacOS / Desktop

Version Number: 1.3.49.0

Reproducible in staging?: Yes

Reproducible in production?: Yes

If this was caught during regression testing, add the test name, ID and link from TestRail:

Email or phone of affected tester (no customers):

Logs: https://stackoverflow.com/c/expensify/questions/4856

Notes/Photos/Videos: Any additional supporting documentation

Bug6150602_Video_2023-08-02_12-10-52-1.mp4

Expensify/Expensify Issue URL:

Issue reported by: Applause - Internal Team

Slack conversation:

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[melvin-bot]

Triggered auto assignment to @garrettmknight (Bug), see https://stackoverflow.com/c/expensify/questions/14418 for more details.

[melvin-bot]

Bug0 Triage Checklist (Main S/O)

• This "bug" occurs on a supported platform (ensure Platforms in OP are ✅)
• This bug is not a duplicate report (check E/App issues and #expensify-bugs)
  • If it is, comment with a link to the original report, close the issue and add any novel details to the original issue instead
• This bug is reproducible using the reproduction steps in the OP. S/O
  • If the reproduction steps are clear and you're unable to reproduce the bug, check with the reporter and QA first, then close the issue.
  • If the reproduction steps aren't clear and you determine the correct steps, please update the OP.
• This issue is filled out as thoroughly and clearly as possible
  • Pay special attention to the title, results, platforms where the bug occurs, and if the bug happens on staging/production.
• I have reviewed and subscribed to the linked Slack conversation to ensure Slack/Github stay in sync

[hnkuanx]

Proposal

Please re-state the problem that we are trying to solve in this issue.

When image attachment is opened several times in Native apps, sometimes the loading icon is shown forever and the image preview does not load.

What is the root cause of that problem?

In ImageView (index.native.js), we have callback function logics to set
isLoading: true in onLoadStart callback; and
isLoading: false in onLoad callback;

see:

App/src/components/ImageView/index.native.js

Lines 225 to 226 in 2f750ad

	onLoadStart={this.imageLoadingStart}
	onLoad={this.configureImageZoom}

That works well when it is the first time the image is being opened, onLoadStart get called first when loading start, and onLoad get called later when loading ends.

However, when an image is being opened more than once, it is already cached, so technically the image does not need to be loaded anymore, onLoadStart and onLoad callbacks actually fires at the same time in these cases.
Sometimes onLoadStart fires first, and we have no problem.
Other times, onLoad fires first, followed by onLoadStart, in this scenario, isLoading state is set to false and then true, thus the loading icon is shown forever instead of image preview.

What changes do you think we should make in order to solve the problem?

We actually do not need to configure onLoadStart callback, as its purpose is to resetImageZoom whenever the source image URL changes.
That is already handled via componentDidUpdate component lifecycle function, which is already calling resetImageZoom whenever the URL changes.

App/src/components/ImageView/index.native.js

Lines 63 to 68 in 2f750ad

	componentDidUpdate(prevProps) {
	if (this.props.url === prevProps.url) {
	return;
	}
	this.imageLoadingStart();

To resolve the issue, we should unset onLoadStart by removing this line

App/src/components/ImageView/index.native.js

Line 225 in 2f750ad

onLoadStart={this.imageLoadingStart}

What alternative solutions did you explore? (Optional)

If the indeterministic firing sequence of onLoadStart and onLoad when image does not requires loading (when already cached) is considered as a bug in upstream library react-native-fast-image, then we can also choose to submit a PR fix upstream.

[gadhiyamanan]

might be same root cause #22920

[garrettmknight]

@gadhiyamanan agreed, I think this looks like the same root cause. Let's put this on hold and leave this open until this PR is deployed. I'll retest and see if that fixed it.

[garrettmknight]

Still holding

[garrettmknight]

Still holding