fix(workflows): reject a switch expression that is never evaluated

[ntdatt812]

The defect

SwitchStep.validate checks only that expression is present (steps/switch/__init__.py:105). The field goes through the same evaluate_expression as a condition, so one written without braces comes back as its own source text.

Measured on main (27f50f7), inputs.mode = "review", cases review / build, plus a default:

expression: inputs.mode
  validate  -> []
  status    -> COMPLETED
  output    -> {'matched_case': '__default__', 'expression_value': 'inputs.mode'}

expression: {{ inputs.mode }}      (control)
  status    -> COMPLETED
  output    -> {'matched_case': 'review', 'expression_value': 'review'}

It matches no case key, falls through to default on every run — or, with no default:, dispatches nothing at all — and still reports COMPLETED. That is exactly the "silent empty result + COMPLETED" wiring bug this file's own cases: guard was written to prevent, quoting its comment, on the field one line above it.

if, while and do-while all run condition_is_never_evaluated and condition_has_malformed_expression_block on their condition. switch ran neither on its expression.

The fix

Reuse those two predicates rather than write a third scan, with switch-appropriate wording.

Only those two apply, deliberately. A switch matches on strings, so a composite key is legitimate here even though the same shape is a fault in a boolean condition:

expression	flagged?	why
inputs.mode	yes	never evaluated
{{ inputs.x	yes	unclosable block
{{ inputs.missing | default('oops }}	yes	raw-close fallback truncates it
{{ inputs.mode }}	no	the ordinary form
{{ inputs.a }}-{{ inputs.b }}	no	composite case key
true, ""	no	ordinary case keys

The last two rows are the condition-specific exemptions condition_is_never_evaluated already carries. They are harmless on a condition and actively correct here, which is what makes these two predicates safe to reuse on a non-boolean field. There is a test pinning that boundary so a later narrowing cannot quietly reject composite keys.

This is independent of #4292, deliberately: that PR adds a predicate for a condition holding more than one block, which is precisely the shape a switch is allowed to have. It is not applied here.

Verification

Windows, Python 3.11.

tests/test_workflows.py -k Switch                       25 passed  (22 before)
tests/test_workflows.py + test_condition_expression_block.py
  + tests/test_extensions.py                            22 failed, 1731 passed
main, same three files                                  22 failed, 1728 passed

Identical 22 failures on both sides, diff clean — the pre-existing symlink and bash-parity classes on unelevated Windows. 1728 → 1731 is exactly the three cases added.

Mutation-checked, after confirming the edit applied: disabling the never-evaluated branch fails 2 of the 3 new cases, and the composite-key case stays green under it — which is the point, since it does not depend on the branch and still guards the other side.

Tests

tests/test_workflows.py::TestSwitchStep — three cases: the braceless form (asserting the current runtime behaviour first, then the validator), both unclosable shapes, and the composite-key/literal boundary that must stay accepted.

AI disclosure

Per CONTRIBUTING: this pull request (code, tests and description) was developed with Claude Code as a coding agent.

[Copilot]

🟡 Changes recommended

The validator incorrectly rejects valid non-boolean string literals used as switch values.

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Pull request overview

Adds switch-expression validation to catch unevaluated or malformed expression blocks.

Changes:

• Reuses existing condition-expression predicates for switch validation.
• Adds regression and boundary tests.

File summaries

File	Description
src/specify_cli/workflows/steps/switch/__init__.py	Validates switch expressions.
tests/test_workflows.py	Covers invalid and accepted expression forms.

Review details

• Files reviewed: 2/2 changed files
• Comments generated: 1
• Review effort level: Balanced

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[ntdatt812]

Right: reusing the condition predicate was wrong for a switch. A condition is coerced by bool(), so any braceless text is always true there. A switch matches its value against case keys, and a case key is a literal, so expression: review is a valid (if constant) switch and whitespace strips to the "" key.

Fixed in 2554a12. switch_expression_is_never_evaluated flags braceless text only when it opens by walking into a root _build_namespace supplies (inputs.mode, item[0], context.run_id, ...), and keeps the verbatim-unclosable {{ case.

• test_a_literal_expression_stays_accepted runs review, whitespace, approve me and a bare inputs through execute() first, asserts the case each one actually dispatches, then asserts validate() accepts it. inputsX.mode is accepted too: a name that merely starts like a root is not a reference into it.
• test_every_namespace_root_written_without_a_block_is_rejected covers every root, plus a filter, a comparison and surrounding whitespace.

[mnriem]

Please address Copilot feedback

[ntdatt812]

@mnriem Copilot's point is addressed in 2554a12 (details in the inline reply), and the branch is rebased onto current main. Ready for re-review.

Evidence:

• TestSwitchStep: 24 passed.
• Mutations, each one reverted afterwards: restoring the condition predicate fails the literal test; making the braceless branch always false fails 2 tests; dropping the ./[ requirement after the root fails 1.
• uvx ruff@0.15.0 check src tests: clean.
• Full tests/test_workflows.py + tests/unit on Windows: 22 failures, all symlink-privilege errors (WinError 1314). The same test fails identically on a clean checkout of main.

AI disclosure, per CONTRIBUTING: this change, its tests and this comment were written with Claude Code as a coding agent; the runs above were executed locally.