⚡ perf: pre-allocate slice capacity in parseSystem

[matdev83]

💡 What: Modified internal/plugins/frontends/anthropic/decode.go to preallocate the parts slice in parseSystem with make([]lipapi.Part, 0, len(blocks)) instead of declaring a nil slice var parts []lipapi.Part.
🎯 Why: Pre-allocating slice capacity when the number of elements is known (e.g. from the length of the slice being iterated over) prevents multiple reallocations during append.
📊 Measured Improvement:
Measured with a benchmark parsing a mocked request with 10 system blocks:

Baseline:
180 allocs/op, 14971 B/op, 57572 ns/op

Improvement:
176 allocs/op, 11050 B/op, 56716 ns/op

This results in a small reduction in memory allocations (fewer append re-allocations) and a slight speed improvement.

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PR created automatically by Jules for task 12487070078391722433 started by @matdev83

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[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

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Run ID: 523dca4e-a235-4302-8267-52743d5c1330

📥 Commits

Reviewing files that changed from the base of the PR and between 02325fe and 8860bbb.

📒 Files selected for processing (1)

• internal/plugins/frontends/anthropic/decode.go

📜 Recent review details

⏰ Context from checks skipped due to timeout. (1)

• GitHub Check: qa

🧰 Additional context used

📓 Path-based instructions (3)

**/*.go

📄 CodeRabbit inference engine (Custom checks)

For server, CLI, worker, or network code, check that context.Context is propagated correctly, cancellation is respected, and new goroutines cannot leak indefinitely

Files:

• internal/plugins/frontends/anthropic/decode.go

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⚙️ CodeRabbit configuration file

**/*.go: Review as production Go code. Prioritize correctness, race conditions, goroutine leaks, context cancellation, timeout handling, error wrapping, nil-pointer risks, resource cleanup, defer placement, API compatibility, interface design, dependency boundaries, and testability. Avoid generic style comments when gofmt/golangci-lint already covers the issue.

Files:

• internal/plugins/frontends/anthropic/decode.go

internal/plugins/frontends/**/*.go

📄 CodeRabbit inference engine (AGENTS.md)

In internal/plugins/frontends/, implement OpenAI Responses, OpenAI legacy, Anthropic, and Gemini frontends.

Files:

• internal/plugins/frontends/anthropic/decode.go

internal/**

⚙️ CodeRabbit configuration file

internal/**: Focus on package boundaries, hidden coupling, unexported API design, concurrency safety, deterministic behavior, and whether logic belongs in this internal package.

Files:

• internal/plugins/frontends/anthropic/decode.go

🔇 Additional comments (1)

internal/plugins/frontends/anthropic/decode.go (1)

152-152: LGTM!

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📝 Walkthrough

Summary by CodeRabbit

• Refactor
  • Improved an internal message-processing step for slightly better efficiency, with no change to user-facing behavior.

Walkthrough

In parseSystem, the parts slice initialization changes from a nil declaration to make(..., 0, len(blocks)), preallocating capacity equal to the number of blocks. No other logic changes.

Anthropic decode fix

Layer / File(s)	Summary
parseSystem slice preallocation internal/plugins/frontends/anthropic/decode.go	parts slice is initialized with make([]T, 0, len(blocks)) instead of a nil slice to preallocate capacity.

🎯 1 (Trivial) | ⏱️ ~2 minutes

🚥 Pre-merge checks | ✅ 7 | ❌ 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 (7 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly matches the technical change and uses an appropriate perf prefix.
Description check	✅ Passed	The description directly explains the same slice preallocation change and its performance impact.
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.
No Secrets	✅ Passed	Only a slice preallocation change in parseSystem; no credentials, tokens, passwords, private keys, or sensitive URLs are introduced.
Context Propagation	✅ Passed	decode.go only preallocates a slice in parseSystem; no context, goroutine, or cancellation paths were added or changed.
No Accidental Public Api Break	✅ Passed	Only parseSystem’s slice preallocation changed in an internal package; no exported types, signatures, JSON fields, flags, or config keys changed.

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