refactor: simplify and de-duplicate utility helpers

[appleboy]

Summary

Quality-only cleanups from a /simplify pass over the library. No public API changes — all tests pass. One small, intentional behavior change (see below).

• array: Contains now delegates to the stdlib slices.Contains instead of a hand-rolled loop (same signature/behavior).
• bytesconv: Removed bytesconv_1.19.go (//go:build !go1.20), which is unreachable under the module's go 1.25.10 requirement. Dropped the now-always-true go1.20 build tag from the survivor and renamed it to bytesconv.go.
• convert: ToString gains a typed fast path for string/*string, avoiding fmt.Sprintf reflection on the most common input. Collapsed three if value != 0 { return true } return false blocks in ToBool to return value != 0.
• file: Extracted the two duplicated close-error defer closures in Copy into a single closeFile(f, role) helper.

Behavior change

• file.Copy — close-error diagnostics now go to stderr (fmt.Fprintf(os.Stderr, ...)) instead of stdout. Previously these messages were printed to stdout, which could corrupt a caller's intended stdout data (e.g. when piping). This is an intentional fix; the only observable difference is the stream these diagnostic lines are written to.

Verification

• go build ./... — clean
• go vet ./... — clean
• go test ./... — all packages pass

Out of scope (flagged for a follow-up /code-review)

The simplify pass also surfaced potential correctness/behavior issues that were intentionally not touched here: ToFloat/ToBool have narrower numeric/pointer type coverage than ToInt (e.g. ToFloat(int64(...)) returns 0.0). These are behavior changes and belong in a separate review.

🤖 Generated with Claude Code

[Copilot]

Pull request overview

This PR performs internal refactors and small simplifications across utility packages, aiming to reduce duplication and rely on standard library helpers where possible.

Changes:

• array.Contains now delegates to slices.Contains.
• bytesconv removes the Go 1.19 fallback file and drops the go1.20 build tag from the remaining implementation.
• convert.ToString adds typed fast paths for string/*string, and convert.ToBool is simplified with direct boolean expressions.
• file.Copy de-duplicates close-error handling via a shared closeFile helper.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
file/file.go	Extracts duplicated deferred close-error handling into closeFile.
convert/convert.go	Adds string fast path to ToString; simplifies ToBool numeric checks.
bytesconv/bytesconv.go	Removes the Go version build constraint from the remaining implementation.
bytesconv/bytesconv_1.19.go	Deletes the Go 1.19-specific implementation file.
array/array.go	Replaces manual loop with slices.Contains.

Comments suppressed due to low confidence (1)

bytesconv/bytesconv.go:3

• Dropping the go1.20 build tag here (and removing the !go1.20 implementation) effectively removes the version-gated selection described in bytesconv/README.md (which still mentions Go 1.19 support/build tags). If Go <1.20 support is no longer intended, the docs should be updated accordingly; otherwise, the 1.19 implementation/build tags need to remain.

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[Copilot]

Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated 1 comment.

[Copilot]

Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated 1 comment.

[Copilot]

Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated 1 comment.

[Copilot]

Pull request overview

Copilot reviewed 8 out of 8 changed files in this pull request and generated no new comments.