Fix HTML trailing newline accessibility crash

[dalinaum]

Summary

• Trim only trailing rendered line breaks from parsed HTML AnnotatedString output.
• Preserve interior newlines and paragraph/list formatting while avoiding a trailing text boundary that can crash Compose accessibility.
• Add regression tests for trailing <br> and compact list output.

Crash Context

Crashlytics issue: https://console.firebase.google.com/u/0/project/hackerspub-android/crashlytics/app/android:pub.hackers.android/issues/970e0c4edebb1afa31c7867b373dec64?time=7d&types=crash&sessionEventKey=69E6FD270331000138BB1A3827BF86CE_2209511287297688744

Relevant stack trace path:

Fatal Exception: java.lang.IllegalArgumentException: Found paragraph index -2 should be in range [0, 1).
Debug info: index=2420, paragraphs=[[0, 2420)]
  at androidx.compose.ui.text.MultiParagraphKt.findParagraphByIndex(MultiParagraph.kt:1244)
  at androidx.compose.ui.text.MultiParagraph.getBoundingBox(MultiParagraph.kt:647)
  at androidx.compose.ui.text.TextLayoutResult.getBoundingBox(TextLayoutResult.kt:503)
  at androidx.compose.ui.platform.AndroidComposeViewAccessibilityDelegateCompat.addExtraDataToAccessibilityNodeInfoHelper(AndroidComposeViewAccessibilityDelegateCompat.android.kt:1785)

The key detail is index=2420 with paragraphs=[[0, 2420)]: accessibility requested a character bounding box at the paragraph end boundary. That boundary can happen when our HTML parser leaves a trailing rendered newline in a ClickableText node. A trailing newline is part of the text range but does not have a drawable glyph bounding box inside the laid-out paragraph.

This looks like a Compose text/accessibility bug as well: Compose should defensively ignore the request or return null for that character-location entry instead of crashing the app. Since the app can avoid feeding this vulnerable trailing boundary without changing user-visible content, this PR normalizes the parsed HTML output by trimming only trailing \n characters.

Verification

./gradlew testDebugUnitTest --tests pub.hackers.android.ui.components.HtmlContentKtTest
BUILD SUCCESSFUL

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 83e0d7cf-9ec1-4b6c-826d-c6e67b66dcbc

📥 Commits

Reviewing files that changed from the base of the PR and between 31cf139 and b33f087.

📒 Files selected for processing (2)

• app/src/main/java/pub/hackers/android/ui/components/HtmlContent.kt
• app/src/test/java/pub/hackers/android/ui/components/HtmlContentKtTest.kt

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📝 Walkthrough

Walkthrough

The parseHtmlToAnnotatedString function now post-processes its result by removing trailing newline characters through a new private extension AnnotatedString.trimTrailingLineBreaks(). Unit tests were added to verify the trimming behavior with HTML inputs ending in <br> tags and list elements.

Changes

Cohort / File(s)	Summary
HTML Content Post-processing app/src/main/java/pub/hackers/android/ui/components/HtmlContent.kt	Added private extension function trimTrailingLineBreaks() that post-processes AnnotatedString to remove trailing \n characters by finding the last non-newline index and returning a subsequence.
HTML Content Unit Tests app/src/test/java/pub/hackers/android/ui/components/HtmlContentKtTest.kt	Added two test cases verifying that parseHtmlToAnnotatedString removes trailing newlines from HTML input ending with <br> tags and from unordered list elements.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and specifically describes the main change: fixing a crash caused by trailing newlines in HTML parsing affecting accessibility.
Description check	✅ Passed	The description comprehensively explains the problem, root cause, solution, and provides verification details directly related to the changeset.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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