サンプル

Distinguish winnow error handling paths where alt combinator discards deep branch errors in favor of the last branch unless cut_err is used, try_map failures yield recoverable Backtrack rather than fatal Cut, and ContextError formatting displays only the innermost label while InputError drops context annotations entirely

sha256:37c7408540f30c3e0ea78c7a69f7ddb967574c1c9fbfebcf11fbf25d3bbe07d5

ケース

ゴール

Distinguish winnow error handling paths where alt combinator discards deep branch errors in favor of the last branch unless cut_err is used, try_map failures yield recoverable Backtrack rather than fatal Cut, and ContextError formatting displays only the innermost label while InputError drops context annotations entirely HOW

パッケージ

winnow 1.0.4

環境

rust

作成日

2026-08-16T12:43:07Z

よくある思い込み

When an alt combinator fails on invalid input after partially matching an alternative, ContextError preserves the error details and byte offset from whichever branch parsed deepest.

このサンプルの作者が、ここで開発者やモデルが期待するであろうこととして記録したもの。下の契約が実際に実行されたものだ。

コントラクト

• assert alt with ContextError discards a partial match in an earlier branch and returns the error and offset of the last evaluated branch, while cut_err prevents backtrack and preserves the deep failure site
• assert try_map produces ErrMode::Backtrack rather than Cut on external validation failure so alt continues trying subsequent branches
• assert TreeError preserves all failed branches of an alt in a hierarchical Alt structure rather than overwriting them with the last branch
• assert InputError ignores AddContext labels and records the remaining input slice, whereas ContextError formats the innermost StrContext::Label and all Expected tokens but renders empty if unannotated
• assert Parser::parse erases the ErrMode modal distinction into ParseError and reports the offset of trailing unconsumed input when the inner parser succeeds partially

ファイル

• Cargo.lock
• Cargo.toml
• NOTES.md
• csx.json
• src/lib.rs

検証済みアーティファクトをダウンロード (tar.gz) — 契約が実行された正確なバイト列

オリジンシーダー

csx-seed

検証レシート

• rust 1 · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · cargo@1 · 2026-08-16 · ed25519:d91480838ac982c9