Fix: react-native-pdf scanner - event coalescing

[mavrickdeveloper]

Explanation of Change

• This PR fixes the Android issue where selecting a local PDF receipt can immediately bounce the user back to the camera view instead of attaching the receipt and continuing to Confirm details.

Root Cause:

• On Android/Fabric, react-native-pdf emits both loadComplete and pageChanged through the same native event path (TopChangeEvent / topChange).
• TopChangeEvent inherited React Native's default coalescing behavior, so Fabric could coalesce those events for the same PDF view.
• In practice, pageChanged could replace loadComplete before JS received it.
• That meant native Android successfully loaded the PDF, but JS sometimes never received onLoadComplete, so receipt validation failed and the flow jumped back instead of attaching the PDF.

Solution:

• Add a react-native-pdf patch that makes TopChangeEvent non-coalescible by returning false from canCoalesce().
• Keep the app-side success path tied to onLoadComplete in PDFThumbnail instead of relying on onPageChanged as a fallback.
• This fixes the library-level event loss itself instead of introducing another workaround.

Validation evidence:

• Before the fix, native emitted both loadComplete and pageChanged, but JS only received pageChanged.
• After the fix, JS received loadComplete and then pageChanged, and the Android receipt flow reached Confirm details without the old onPageChanged success fallback.

Fixed Issues

$ #81225
PROPOSAL: #81225 (comment)

Tests

Prerequisites:

• Android app build from this branch
• A local PDF file available on the Android device/emulator

Primary Test (original issue):

1. Open the Android app
2. Tap FAB +
3. Tap Create expense
4. Tap the photo icon
5. Tap Choose file
6. Select a local PDF from device storage
7. Verify the app does not jump back to the camera view
8. Verify the flow continues to Confirm details with the PDF receipt attached

Repeatability / regression check:

9. From Confirm details, go back to the scan step
10. Select another local PDF
11. Verify the flow again continues to Confirm details

• Verify that no errors appear in the JS console during the Android validation flow

Offline tests

N/A - The fix changes Android native-to-JS event delivery for local PDF callbacks inside react-native-pdf. It does not depend on network state. The original failure happened after selecting a local file, before the problem was about uploading over the network.

QA Steps

1. On Android, reproduce the original issue steps from the OP:
   1. Open the app
   2. Tap FAB +
   3. Tap Create expense
   4. Tap the photo icon
   5. Tap Choose file
   6. Select a local PDF
2. Verify the app stays in the expense flow instead of switching back to the camera view
3. Verify the flow reaches Confirm details with the PDF attached
4. Go back from Confirm details
5. Upload another local PDF
6. Verify the second PDF also reaches Confirm details
7. Verify no JS console errors appear

Notes

• Local root-cause validation was performed on the standalone Android emulator flow because Mobile-Expensify could not be initialized in this workspace.
• QA should validate the same behavior on the normal Android app/staging flow for the final merge signal.

PR Author Checklist

• I linked the correct issue in the ### Fixed Issues section above
• I wrote clear testing steps that cover the changes made in this PR
  • I added steps for local testing in the Tests section
  • I added steps for the expected offline behavior in the Offline steps section
  • I added steps for Staging and/or Production testing in the QA steps section
  • I added steps to cover failure scenarios (i.e. verify an input displays the correct error message if the entered data is not correct)
  • I turned off my network connection and tested it while offline to ensure it matches the expected behavior (i.e. verify the default avatar icon is displayed if app is offline)
  • I tested this PR with a High Traffic account against the staging or production API to ensure there are no regressions (e.g. long loading states that impact usability).
• I included screenshots or videos for tests on all platforms
• I ran the tests on all platforms & verified they passed on:
  • Android: Native
  • Android: mWeb Chrome
  • iOS: Native
  • iOS: mWeb Safari
  • MacOS: Chrome / Safari
  • Windows: Chrome
• I verified there are no console errors (if there's a console error not related to the PR, report it or open an issue for it to be fixed)
• I verified there are no new alerts related to the canBeMissing param for useOnyx
• I followed proper code patterns (see Reviewing the code)
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    • If any non-english text was added/modified, I used JaimeGPT to get English > Spanish translation. I then posted it in #expensify-open-source and it was approved by an internal Expensify engineer. Link to Slack message:
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• I tested other components that can be impacted by my changes (i.e. if the PR modifies a shared library or component like Avatar, I verified the components using Avatar are working as expected)
• I verified all code is DRY (the PR doesn't include any logic written more than once, with the exception of tests)
• I verified any variables that can be defined as constants (ie. in CONST.ts or at the top of the file that uses the constant) are defined as such
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• If the PR modifies a generic component, I tested and verified that those changes do not break usages of that component in the rest of the App (i.e. if a shared library or component like Avatar is modified, I verified that Avatar is working as expected in all cases)
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• If the PR modifies a component or page that can be accessed by a direct deeplink, I verified that the code functions as expected when the deeplink is used - from a logged in and logged out account.
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• I added unit tests for any new feature or bug fix in this PR to help automatically prevent regressions in this user flow.
• If the main branch was merged into this PR after a review, I tested again and verified the outcome was still expected according to the Test steps.

Screenshots/Videos

Android: Native

Android: mWeb Chrome

iOS: Native

iOS: mWeb Safari

MacOS: Chrome / Safari

[github-actions]

⚠️ This PR is possibly changing native code and/or updating libraries, it may cause problems with HybridApp. Please check if any patch updates are required in the HybridApp repo and run an AdHoc build to verify that HybridApp will not break. Ask Contributor Plus for help if you are not sure how to handle this. ⚠️

[codecov]

Codecov Report

❌ Looks like you've decreased code coverage for some files. Please write tests to increase, or at least maintain, the existing level of code coverage. See our documentation here for how to interpret this table.

Files with missing lines	Coverage Δ
src/components/PDFThumbnail/index.native.tsx	16.66% <0.00%> (-1.52%)	⬇️
... and 8 files with indirect coverage changes