# Contributor handoff — gotestyourself/gotestsum

> Canonical page: https://codevetter.com/unpack/gotestsum/agent-handoff

# Contributor handoff — gotestyourself/gotestsum

Scanned commit 3cf14356a16c7931cfeacd7dfee585527618df3d (2026-04-14). Generated by codevetter codevetter 1.15.0 on 2026-10-02.

Source inspection; upstream code and tests were not executed.

Begin with the executable router, command lifecycle, event model, and handler boundaries before changing behavior. Preserve test-instance identity, compatibility workarounds, and distinctions between raw event logs and synthesized failures. Tests and CI were inspected, not executed; future execution requires authorization beyond this read-only investigation. Use the bounded evidence here as navigation, then inspect the affected implementation and adjacent tests.
- Read README.md, go.mod, main.go, cmd/main.go, cmd/handler.go, and testjson/execution.go first to establish user contracts, toolchain requirements, routing, execution ordering, and event state. — [README.md#L15-L34](https://github.com/gotestyourself/gotestsum/blob/3cf14356a16c7931cfeacd7dfee585527618df3d/README.md#L15-L34) [go.mod#L1-L16](https://github.com/gotestyourself/gotestsum/blob/3cf14356a16c7931cfeacd7dfee585527618df3d/go.mod#L1-L16) [main.go#L28-L38](https://github.com/gotestyourself/gotestsum/blob/3cf14356a16c7931cfeacd7dfee585527618df3d/main.go#L28-L38) [cmd/main.go#L279-L347](https://github.com/gotestyourself/gotestsum/blob/3cf14356a16c7931cfeacd7dfee585527618df3d/cmd/main.go#L279-L347)
- Keep flag changes aligned with setupFlags, options.Validate, and child argument construction; reruns with forwarded Go arguments require --packages, and -(test.)failfast is rejected. — [cmd/main.go#L53-L64](https://github.com/gotestyourself/gotestsum/blob/3cf14356a16c7931cfeacd7dfee585527618df3d/cmd/main.go#L53-L64) [cmd/main.go#L223-L235](https://github.com/gotestyourself/gotestsum/blob/3cf14356a16c7931cfeacd7dfee585527618df3d/cmd/main.go#L223-L235) [cmd/main.go#L350-L387](https://github.com/gotestyourself/gotestsum/blob/3cf14356a16c7931cfeacd7dfee585527618df3d/cmd/main.go#L350-L387)
- Preserve ID and RunID semantics for repeated tests and reruns; JSON export uses original event bytes, so synthetic EOF failures appear in state and summaries but are deliberately omitted from JSON files. — [testjson/execution.go#L280-L305](https://github.com/gotestyourself/gotestsum/blob/3cf14356a16c7931cfeacd7dfee585527618df3d/testjson/execution.go#L280-L305) [testjson/execution.go#L334-L352](https://github.com/gotestyourself/gotestsum/blob/3cf14356a16c7931cfeacd7dfee585527618df3d/testjson/execution.go#L334-L352) [cmd/handler.go#L59-L68](https://github.com/gotestyourself/gotestsum/blob/3cf14356a16c7931cfeacd7dfee585527618df3d/cmd/handler.go#L59-L68)
- Treat EventHandler callbacks as potentially concurrent: ScanTestOutput launches stdout and stderr readers separately, and Execution protects its error list with a mutex. — [testjson/execution.go#L785-L791](https://github.com/gotestyourself/gotestsum/blob/3cf14356a16c7931cfeacd7dfee585527618df3d/testjson/execution.go#L785-L791) [testjson/execution.go#L667-L681](https://github.com/gotestyourself/gotestsum/blob/3cf14356a16c7931cfeacd7dfee585527618df3d/testjson/execution.go#L667-L681)
- Review both run and runSingle when changing lifecycle or option propagation; watch execution is a documented copy without retry support, and Windows keyboard handling differs from Unix. — [cmd/watch.go#L62-L95](https://github.com/gotestyourself/gotestsum/blob/3cf14356a16c7931cfeacd7dfee585527618df3d/cmd/watch.go#L62-L95) [cmd/main.go#L279-L335](https://github.com/gotestyourself/gotestsum/blob/3cf14356a16c7931cfeacd7dfee585527618df3d/cmd/main.go#L279-L335) [internal/filewatcher/term_windows.go#L5-L19](https://github.com/gotestyourself/gotestsum/blob/3cf14356a16c7931cfeacd7dfee585527618df3d/internal/filewatcher/term_windows.go#L5-L19)
- For separately authorized validation, target the affected Go package first, then consider CI's build and ./gotestsum -f testname -- ./... -race -count=1 sequence; this investigation inspected those tests and CI definitions without executing them. — [.github/workflows/ci.yaml#L23-L28](https://github.com/gotestyourself/gotestsum/blob/3cf14356a16c7931cfeacd7dfee585527618df3d/.github/workflows/ci.yaml#L23-L28) [cmd/main_e2e_test.go#L29-L32](https://github.com/gotestyourself/gotestsum/blob/3cf14356a16c7931cfeacd7dfee585527618df3d/cmd/main_e2e_test.go#L29-L32) [testjson/execution_test.go#L40-L60](https://github.com/gotestyourself/gotestsum/blob/3cf14356a16c7931cfeacd7dfee585527618df3d/testjson/execution_test.go#L40-L60)
- Golden fixtures encode output contracts, and ./do update-golden writes expected results; slowest's --skip-stmt also writes source, so neither belongs in a read-only verification pass. — [testjson/format_test.go#L74-L81](https://github.com/gotestyourself/gotestsum/blob/3cf14356a16c7931cfeacd7dfee585527618df3d/testjson/format_test.go#L74-L81) [do#L16-L18](https://github.com/gotestyourself/gotestsum/blob/3cf14356a16c7931cfeacd7dfee585527618df3d/do#L16-L18) [cmd/tool/slowest/ast.go#L64-L74](https://github.com/gotestyourself/gotestsum/blob/3cf14356a16c7931cfeacd7dfee585527618df3d/cmd/tool/slowest/ast.go#L64-L74)
- Resolve documentation drift from implementation: README lists GOTESTSUM_FORMAT among hook variables, but postRunHook does not explicitly inject it; Docker's default Go version also predates the module directive. — [README.md#L139-L151](https://github.com/gotestyourself/gotestsum/blob/3cf14356a16c7931cfeacd7dfee585527618df3d/README.md#L139-L151) [cmd/handler.go#L170-L180](https://github.com/gotestyourself/gotestsum/blob/3cf14356a16c7931cfeacd7dfee585527618df3d/cmd/handler.go#L170-L180) [.project/Dockerfile#L2-L3](https://github.com/gotestyourself/gotestsum/blob/3cf14356a16c7931cfeacd7dfee585527618df3d/.project/Dockerfile#L2-L3) [go.mod#L1-L3](https://github.com/gotestyourself/gotestsum/blob/3cf14356a16c7931cfeacd7dfee585527618df3d/go.mod#L1-L3)

Every claim links to its cited files at the pinned commit. Citations identify source evidence; they do not establish runtime correctness. Independent CodeVetter scan — not reviewed by upstream maintainers.

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