debugging-failures

Debugging Ginkgo failures (especially as an agent)

Ginkgo's terminal output is good for a human; for programmatic diagnosis, prefer a hybrid: terminal for the verdict, JSON + jq for the details. This is empirically the most reliable, lowest-token workflow. Docs: https://onsi.github.io/ginkgo/#reporting-and-profiling-suites.

The workflow: one run, JSON-first diagnosis

# One invocation gives you BOTH the human verdict on the terminal AND a structured report.
# --json-report does NOT suppress console output, so you don't pay for two runs.
ginkgo -r -p --no-color --json-report=report.json --output-dir=.ginkgo-report

1. Read the terminal tail for the one-line verdict: FAIL! -- 5 Passed | 6 Failed | 1 Pending | 1 Skipped. Cheap, immediate.
2. If there are failures, query the JSON with jq (filters below) to get exactly the failing specs — stable, addressable, order-independent.
3. Clean up the report dir when done.

Why hybrid and not one or the other:

• Terminal-only is brittle to parse (free-form text) and, under -p, interleaves failures in nondeterministic order.
• JSON-only is wasteful if you dump it: the full report.json is ~9× the tokens of the terminal output. A jq failures-only extraction is a fraction of either. The discipline is filter, don't dump.

Where the JSON lands (use --output-dir deliberately)

• --json-report=report.json alone writes report.json to the current directory — which scatters into package dirs under -r and risks getting committed.
• Prefer --output-dir=DIR to collect everything in one known place (auto-created). With -r, all suites merge into one DIR/report.json — ideal: one file, one set of jq filters.
• Use a gitignored or temp location: a repo-local .ginkgo-report/ (add it to .gitignore) or an absolute temp path (--output-dir=/tmp/ginkgo-report). Don't leave report.json in the working tree.
• --keep-separate-reports (with -r) writes one PACKAGE_report.json per package instead of merging — only reach for it when you must attribute failures per package.

The jq filters (tested against the real schema)

The report is an array of suite reports, each with a .SpecReports[] array.

Verdict / counts per suite:

jq -r '.[] | "\(.SuiteDescription): \([.SpecReports[].State]|group_by(.)|map("\(length) \(.[0])")|join(", "))"' .ginkgo-report/report.json

All failures — name, location, message (the workhorse). Select failed and panicked and timedout — see the trap below:

jq -r '.[].SpecReports[]
  | select(.State=="failed" or .State=="panicked" or .State=="timedout")
  | "[\(.State|ascii_upcase)] \((.ContainerHierarchyTexts+[.LeafNodeText])|join(" > "))\n  \(.Failure.Location.FileName):\(.Failure.Location.LineNumber)\n  \(.Failure.Message)"' .ginkgo-report/report.json

Panics — the real user-code line (the headline location lies; see below):

jq -r '.[].SpecReports[] | select(.State=="panicked")
  | "PANIC: \(.Failure.ForwardedPanic)\n\(.Failure.Location.FullStackTrace)"' .ginkgo-report/report.json

Drill into one spec by name, with its captured logs:

jq -r '.[].SpecReports[] | select(.LeafNodeText|test("SUBSTRING"))
  | "STATE: \(.State)\n\(.Failure.Message)\n--- GinkgoWriter ---\n\(.CapturedGinkgoWriterOutput // "(none)")"' .ginkgo-report/report.json

Slowest specs:

jq '.[0].SpecReports | map([(.ContainerHierarchyTexts+[.LeafNodeText])|join(" "), .RunTime/1e9]) | sort_by(.[1]) | reverse | .[0:10]' .ginkgo-report/report.json

Schema facts you need

• State: passed | failed | panicked | pending | skipped | timedout | interrupted | aborted.
• Spec name = ContainerHierarchyTexts (array) + LeafNodeText.
• Failure.Message — the failure text (Gomega's full expected/got block for assertions).
• Failure.Location.{FileName,LineNumber,FullStackTrace}.
• Failure.ForwardedPanic — the panic value (only meaningful for panicked).
• Failure.FailureNodeType — e.g. BeforeEach vs It, so you know a setup node failed.
• CapturedGinkgoWriterOutput — GinkgoWriter logs (omitted if empty).
• SpecEvents[] — By(...) steps and node enter/exit (does not include raw GinkgoWriter text).
• ParallelProcess — which worker ran the spec (-p).

The three traps that bite agents

1. panicked is not failed. select(.State=="failed") silently misses panics. Always include "panicked" (and "timedout").
2. A panic's Location.FileName points into the Go runtime, not your code (e.g. runtime_faststr.go). The real line is in Failure.ForwardedPanic + Failure.Location.FullStackTrace.
3. --fail-fast truncates the report to whatever ran before the stop. For a full failure picture, don't use it — Ginkgo keeps going within a suite by default; use --keep-going with -r so one failing package doesn't stop the others.

Reproduce, then narrow

• Every run prints its random seed. Reproduce the exact order with ginkgo --seed=N.
• Narrow to the failing spec with --focus="<regex over the full name>" or --focus-file=file:line (→ ginkgo:filtering). Avoid committing FIt.
• Re-run the one spec with -v (or -vv --trace) for the full inline timeline — By steps, GinkgoWriter output, and the failure point in execution order. Reserve this verbosity for a specific elusive spec; it's noise across a whole suite.

When it's a hang, not a failure

A stuck spec emits no failure. Get a snapshot of what's running without stopping the suite: send SIGINFO (Ctrl+\ is SIGQUIT; macOS Ctrl+T = SIGINFO) or SIGUSR1 on Linux — Ginkgo prints the current node, goroutine stacks, and the last GinkgoWriter lines (a progress report). Make stuck specs auto-report with --poll-progress-after=120s --poll-progress-interval=30s (or per-node PollProgressAfter). Progress reports also appear in the JSON. → ginkgo:timeouts-and-async for making specs interrupt cleanly.

Other formats

--junit-report / --teamcity-report / --gojson-report exist but lose Ginkgo metadata — use them only to feed an external CI system. For diagnosis, the native --json-report is richer. → ginkgo:reporting.