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Pin down the log/slog Handler contract that custom and third-party handlers have to honour

sha256:6af5bf59ebf30efdf1126ea505e09aa3ffbc7ae1997e37934d4ebacbbdc25dde

ケース

ゴール

Pin down the log/slog Handler contract that custom and third-party handlers have to honour HOW

パッケージ

github.com/lmittmann/tint 1.2.0

環境

go 1.26

作成日

2026-08-14T12:53:34Z

コントラクト

• assert JSONHandler writes time, level and msg in that order under slog's built-in key constants
• assert the JSON timestamp is RFC3339Nano with a variable-length fraction, while TextHandler and tint pad a time attribute to exactly three digits
• assert a zero Record.Time drops the timestamp field entirely
• assert ReplaceAttr renames the level and message keys and drops a field by returning a zero Attr
• assert a ReplaceAttr without a len(groups) guard renames a user attribute named msg inside a group as well
• assert the guard still cannot protect the built-in msg from a top-level attribute of the same name: the record carries two message keys and the JSON decoder keeps the last
• assert only a zero Attr drops a field, while an empty value or an empty key is still written out
• assert ReplaceAttr is called for the built-ins with no open groups and for a group's contents with the group path, never for the group attr itself
• assert WithGroup nests later attributes, an empty group is omitted, and WithGroup with an empty name is a no-op
• assert JSONHandler ignores fmt.Stringer and json-marshals the struct, while LogValue wins on both handlers
• assert Handler.Enabled is consulted and Handle is skipped when the level is disabled
• assert LogValue does not run for a disabled level but plain call arguments are evaluated anyway, and only an explicit Enabled guard skips them
• assert a LogValuer passed to With is resolved once, at With time, and not again per record
• assert WithAttrs and WithGroup each return a new handler, so a child logger's attrs and open group reach neither the parent nor a sibling
• assert tint follows the same ReplaceAttr, group and LogValuer contract but formats a Stringer with %+v and writes ANSI escapes to a non-terminal unless NoColor is set
• assert tint.NewHandler is the constructor deprecated in v1.2.0 and produces output identical to tint.NewTextHandler

ファイル

• csx.json
• go.mod
• go.sum
• src/logging.go
• test/main.go

オリジンシーダー

anonymous

検証レシート

• go 1.26 · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · golang@1 · 2026-08-14 · ed25519:a2ec939a4c60e243
• · CONTAINER_RUN · compile:SKIPPED · contract:FAIL · load:SKIPPED · resolve:PASS · golang@1 · 2026-08-14 · ed25519:7da3f610facce8bf