Accept null file_size in AttachmentDto

[gpunto]

Goal

Backport of #6462 to v6.

It seems that backend can return null for file_size on attachments, but AttachmentDto.file_size was non-nullable so explicit nulls in the JSON caused deserialization to fail.

This also aligns with iOS, where AttachmentFile decodes a missing or non-decodable file_size as 0.

Closes #6428

Implementation

• AttachmentDto.file_size is now Int?, so an explicit null from the API deserializes cleanly.
• DomainMapping maps null to 0 when mapping to the domain Attachment.fileSize.

Testing

• New unit test Deserialize JSON attachment with null file_size covers the parser path.
• Existing attachment parser and mapping tests continue to pass.

Summary by CodeRabbit

• Bug Fixes
  • Improved handling of attachments with missing file size information. The system now gracefully defaults file size to 0 when the value is unavailable, enhancing robustness and preventing potential issues during attachment processing.

[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 ignored for dependabot PRs).

🎉 Great job! This PR is ready for review.

[github-actions]

SDK Size Comparison 📏

SDK	Before	After	Difference	Status
stream-chat-android-client	5.26 MB	5.29 MB	0.03 MB	🟢
stream-chat-android-offline	5.49 MB	5.50 MB	0.01 MB	🟢
stream-chat-android-ui-components	10.64 MB	10.68 MB	0.04 MB	🟢
stream-chat-android-compose	12.87 MB	12.89 MB	0.03 MB	🟢

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

Run ID: 922011e8-142f-4913-9400-8b5daf2b9d01

📥 Commits

Reviewing files that changed from the base of the PR and between 23b37d6 and 6e0a9ce.

📒 Files selected for processing (7)

• stream-chat-android-client/src/main/java/io/getstream/chat/android/client/api2/mapping/DomainMapping.kt
• stream-chat-android-client/src/main/java/io/getstream/chat/android/client/api2/model/dto/AttachmentDto.kt
• stream-chat-android-client/src/main/java/io/getstream/chat/android/client/parser2/direct/AttachmentAdapter.kt
• stream-chat-android-client/src/test/java/io/getstream/chat/android/client/api2/mapping/DomainMappingTest.kt
• stream-chat-android-client/src/test/java/io/getstream/chat/android/client/parser2/AttachmentDtoAdapterTest.kt
• stream-chat-android-client/src/test/java/io/getstream/chat/android/client/parser2/AttachmentParsingTest.kt
• stream-chat-android-client/src/test/java/io/getstream/chat/android/client/parser2/testdata/AttachmentDtoTestData.kt

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Walkthrough

The PR makes AttachmentDto.file_size nullable and updates deserialization, domain mapping, and tests to coalesce null values to 0. This allows the Android SDK to gracefully handle API responses where file_size is explicitly null instead of failing during JSON parsing.

Changes

Attachment file_size null-safety handling

Layer / File(s)	Summary
Attachment DTO nullable contract and JSON parsing stream-chat-android-client/src/main/java/io/getstream/chat/android/client/api2/model/dto/AttachmentDto.kt, stream-chat-android-client/src/main/java/io/getstream/chat/android/client/parser2/direct/AttachmentAdapter.kt, stream-chat-android-client/src/test/java/io/getstream/chat/android/client/parser2/AttachmentDtoAdapterTest.kt	AttachmentDto.file_size changes from non-null Int = 0 to nullable Int? = 0. AttachmentAdapter.fromJson now parses file_size using readNullableInt(...) ?: 0 instead of unconditional nextInt(), allowing null JSON values to coalesce to 0. A new unit test validates deserialization of attachments with file_size: null.
Domain mapping with null-safety coalescing stream-chat-android-client/src/main/java/io/getstream/chat/android/client/api2/mapping/DomainMapping.kt, stream-chat-android-client/src/test/java/io/getstream/chat/android/client/api2/mapping/DomainMappingTest.kt	DomainMapping.toDomain() applies the null-safe operator (file_size ?: 0) when converting AttachmentDto to domain Attachment. Test expectations updated to verify null file_size becomes 0 in the mapped domain model.
Integration test coverage and fixtures stream-chat-android-client/src/test/java/io/getstream/chat/android/client/parser2/AttachmentParsingTest.kt, stream-chat-android-client/src/test/java/io/getstream/chat/android/client/parser2/testdata/AttachmentDtoTestData.kt	AttachmentParsingTest removes exception expectations and instead asserts both DTO and direct parsing paths coalesce null file_size to 0. New test fixtures (jsonWithNullFileSize, attachmentWithNullFileSize) added. Unused exception-related imports removed.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Poem

🐰 A null once broke the parsing chain,
Now defaults smooth the Android rain,
Where file_size was cruel and strict,
We coalesce with graceful trick—
Zero fills the void with care! 🎉

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 28.57% 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 concisely describes the main change: accepting null file_size in AttachmentDto, which directly reflects the core purpose of the PR.
Description check	✅ Passed	The PR description provides Goal, Implementation, and Testing sections matching the template. However, several optional sections (UI Changes, Contributor/Reviewer Checklists) remain uncompleted.
Linked Issues check	✅ Passed	The PR fully addresses issue #6428 by accepting null file_size in the DTO and safely mapping it to 0 in domain models, preventing deserialization failures and misleading NETWORK_FAILED errors.
Out of Scope Changes check	✅ Passed	All code changes directly support the objective of handling null file_size: DTO nullability, domain mapping, parser adapter updates, and corresponding test additions are in scope.

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✨ 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 null-file-size-v6

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[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