fix(cmd): propagate specs file write errors in test-init

[ascandone]

Follow-up to #148 (which you closed) — recreating just the reachable half of that fix.

Background

#148 bundled two fixes: propagating os.WriteFile's error, and propagating json.MarshalIndent's error (via an injectable jsonMarshalIndent var so a test could force a failure). We determined the marshal-error path is unreachable in practice — every field in specs_format.Specs is a string, bool, or *big.Int, none of which encoding/json.Marshal can fail on (no floats, no cycles, no unsupported types, and *big.Int.MarshalJSON always succeeds) — so that half was dropped.

The os.WriteFile half is a real, reachable bug on main today: its error is discarded (_ = os.WriteFile(...)), so test-init prints ✅ Created specs file and exits 0 even when nothing was written (disk full, permission denied, target path already exists as a directory, etc.).

Fix

Propagate os.WriteFile's error instead of discarding it. Left json.MarshalIndent's error un-propagated and inline (no injection seam) — consistent with the rest of the codebase's convention of discarding errors from calls that can't realistically fail (see the _, _ = ... writes throughout specs_format/runner.go).

Test plan

• go test ./internal/cmd/... — new test creates a directory at the target .specs.json path so the write deterministically fails, and asserts the error propagates with a clear message

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 615e6fcc-4964-4db0-8d3b-3ad6b1e3dfa3

📥 Commits

Reviewing files that changed from the base of the PR and between 93f89d1 and b432efe.

📒 Files selected for processing (2)

• internal/cmd/test_init.go
• internal/cmd/test_init_internal_test.go

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Walkthrough

The test initialization command now propagates specs file write errors. A new internal test creates an invalid target path and checks that the command returns the expected error message.

Changes

Test initialization write handling

Layer / File(s)	Summary
Write error handling and regression test internal/cmd/test_init.go, internal/cmd/test_init_internal_test.go	runTestInitCmd now returns a formatted error when os.WriteFile fails. The test verifies this behavior by using a directory at the specs file path.

Estimated code review effort: 2 (Simple) | ~10 minutes

Poem

A rabbit found a silent write,
And made its error known.
A test blocked the target path,
Then checked the message shown.
“Good hops!” the rabbit said.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely describes the primary change: propagating specs file write errors in test-init.
Description check	✅ Passed	The description directly explains the write-error fix, its rationale, and the test coverage.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/test-init-propagate-write-error

Warning

There were issues while running some tools. Please review the errors and either fix the tool's configuration or disable the tool if it's a critical failure.

🔧 golangci-lint (2.12.2)

level=error msg="[linters_context] typechecking error: pattern ./...: directory prefix . does not contain main module or its selected dependencies"

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[NumaryBot]

✅ Approve — automated review

The change correctly propagates write failures from test-init and the added test covers a deterministic failure path. I did not identify any introduced correctness issues in the diff.

No findings.