ably: fix broken log format when presence history data fails to decode

[RaphaelFakhri]

Description

When RESTChannel.Presence.History receives a presence message whose data can't be decoded (for example, an unknown encoding), the SDK logs the failure with %w. The logger formats messages with fmt.Sprintf, which doesn't support %w, so the log line ends with %!w(*errors.errorString=&{unknown encoding nonsense}) instead of the error text.

This change uses %v, which matches the equivalent messages in rest_channel.go.

Testing

Adds TestRESTPresence_HistoryLogsDecodeFailure. It serves a presence history page with an unknown encoding from a local HTTP server, records the log output through WithLogHandler, and asserts that the decode failure is logged without a formatting error and includes the error text.

go test ./ably -run TestRESTPresence_HistoryLogsDecodeFailure -count=1

Without the fix, the test fails with a log line that contains %!w(. With the fix, it passes.

Summary by CodeRabbit

• Bug Fixes
  • Corrected error formatting in diagnostic logs when presence-history messages contain an unsupported encoding, so the reported issue is displayed cleanly.
• Tests
  • Added coverage to verify the diagnostic output for presence-history decoding failures.

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ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Advanced

Run ID: 892ecb93-622c-4021-86dc-80f43c7b1237

📥 Commits

Reviewing files that changed from the base of the PR and between 26cb171 and 41b41cc.

📒 Files selected for processing (2)

• ably/rest_presence.go
• ably/rest_presence_test.go

Included review availability: This review used your included allowance. Your plan provides up to 1 included review per hour; 0 remain after this review.

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Walkthrough

The presence-message decode-failure log now formats errors with %v instead of %w. A REST presence-history test verifies the log message for an unknown encoding.

Changes

Presence decode log

Layer / File(s)	Summary
Decode log formatting and test ably/rest_presence.go, ably/rest_presence_test.go	The decode-failure log uses %v. A REST history test uses an unknown encoding and checks that the logged message contains the encoding without a formatting error.

Priority: ⬇️ Low

Estimated code review effort: 2 (Simple) | ~8 minutes

Change: Bug fix

Merge Risk: ⚪ Minimal · up to 41b41

The change corrects presence-history decode-failure logs, and the added test checks the resulting diagnostic. No material merge risk remains.

🚥 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%. Docstring coverage is scoped to functions touched by this diff. Analyzed 1 functions across 2 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the main change: fixing the broken log format for presence-history decode failures.
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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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create a new PR

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