ui-common: Show mention suggestions after non-alphanumeric dividers

[gpunto]

Goal

Typing a mention right after a comma (e.g. @john,@jane) did not reveal suggestions for the second mention. TypingSuggester only accepted the @ symbol at the start of the input or after whitespace, so any non-whitespace divider in front of it was rejected.

Reported during QA: Android QA - Mentions

Closes AND-1276

Implementation

• TypingSuggester now accepts the symbol unless it is glued directly to a letter or digit. This covers commas and other separators (punctuation, brackets) while still rejecting cases like Hello@john and email addresses (john@example.com).

Testing

• New TypingSuggesterTest cases: comma-divided mentions (@john,@jane), a bracket divider ((@john), and an email that must not trigger (john@example.com).

Summary by CodeRabbit

• Bug Fixes
  • Improved mention detection in the message composer so typing suggestions no longer trigger on email-like text.
  • Mention suggestions now work more reliably around punctuation and when multiple mentions appear in a message.
  • Expanded typing behavior checks to cover additional real-world input patterns, including parentheses and comma-separated mentions.

[github-actions]

PR checklist ✅

All required conditions are satisfied:

• Title length is OK (or ignored by label).
• At least one pr: label exists.
• Sections ### Goal, ### Implementation, and ### Testing are filled, or the PR is bot-authored.
• An issue is linked (Linear ticket or GitHub issue), or the PR is bot-authored.

🎉 Great job! This PR is ready for review.

[github-actions]

SDK Size Comparison 📏

SDK	Before	After	Difference	Status
stream-chat-android-client	5.93 MB	5.93 MB	0.00 MB	🟢
stream-chat-android-ui-components	11.19 MB	11.19 MB	0.00 MB	🟢
stream-chat-android-compose	12.65 MB	12.65 MB	0.00 MB	🟢

[coderabbitai]

Walkthrough

The isValidPosition logic in TypingSuggester.typingSuggestion is updated to allow the trigger symbol after any non-alphanumeric character (not just whitespace or start-of-input). Four new parameterized test cases are added to verify multi-mention, parenthesis-preceded, and email-like inputs.

TypingSuggester Trigger Validation

Layer / File(s)	Summary
isValidPosition logic and new test cases ...composer/typing/TypingSuggester.kt, ...composer/typing/TypingSuggesterTest.kt	isValidPosition now checks that the character before the trigger is not a letter or digit (via getOrNull). New test cases cover @john,@jane, `@john, `@jane, (@john``, and john@example.com.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~5 minutes

Possibly related PRs

• GetStream/stream-chat-android#6526: Directly modifies the same TypingSuggester.typingSuggestion parsing flow, rejecting suggestions whose extracted token starts with whitespace.

Suggested reviewers

• andremion

🐇 A comma or paren, no longer a wall,
The @ may follow them, one and all!
But letters and digits still block the way,
So emails won't trigger a mention today.
Hop hop, the suggester now works with flair! 🎉

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 50.00% 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 matches the main change: showing mention suggestions after non-alphanumeric dividers.
Description check	✅ Passed	The description covers the required Goal, Implementation, and Testing sections and is complete enough for this change.
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.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/comma-separated-mention-suggestions

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[coderabbitai]

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Review finished.

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[coderabbitai]

🧹 Nitpick comments (1)

stream-chat-android-ui-common/src/test/kotlin/io/getstream/chat/android/ui/common/feature/messages/composer/typing/TypingSuggesterTest.kt (1)

48-51: 📐 Maintainability & Code Quality | 🔵 Trivial | ⚡ Quick win

Add a digit-adjacent negative case.

The new contract is “not attached to a letter or digit”, but these additions only lock down punctuation and letter/email cases. A case like 1@john or room2@john returning null would keep the isDigit() half of Line 45 covered.

Suggested test addition

             Arguments.of("Hello@john", null),
+            Arguments.of("1@john", null),
             Arguments.of("`@john`,`@jane`", TypingSuggestion("jane", 7 until 11)),
             Arguments.of("`@john`, `@jane`", TypingSuggestion("jane", 8 until 12)),
             Arguments.of("(`@john`", TypingSuggestion("john", 2 until 6)),

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In
`@stream-chat-android-ui-common/src/test/kotlin/io/getstream/chat/android/ui/common/feature/messages/composer/typing/TypingSuggesterTest.kt`
around lines 48 - 51, Add a new negative test case in TypingSuggesterTest to
cover the “not attached to a letter or digit” contract for
TypingSuggester.suggestTypingSuggestion. Extend the existing parameterized data
near the current email and punctuation cases with an input like 1@john or
room2@john that must return null, so the isDigit() branch in the
typing-suggestion boundary check is explicitly covered.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In
`@stream-chat-android-ui-common/src/test/kotlin/io/getstream/chat/android/ui/common/feature/messages/composer/typing/TypingSuggesterTest.kt`:
- Around line 48-51: Add a new negative test case in TypingSuggesterTest to
cover the “not attached to a letter or digit” contract for
TypingSuggester.suggestTypingSuggestion. Extend the existing parameterized data
near the current email and punctuation cases with an input like 1@john or
room2@john that must return null, so the isDigit() branch in the
typing-suggestion boundary check is explicitly covered.

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

Run ID: 52141207-2fc2-40ae-8b9f-0baf840a45e3

📥 Commits

Reviewing files that changed from the base of the PR and between 7b99f38 and f1b5870.

📒 Files selected for processing (2)

• stream-chat-android-ui-common/src/main/kotlin/io/getstream/chat/android/ui/common/feature/messages/composer/typing/TypingSuggester.kt
• stream-chat-android-ui-common/src/test/kotlin/io/getstream/chat/android/ui/common/feature/messages/composer/typing/TypingSuggesterTest.kt

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud