fix(workflows): reject non-string 'condition' in if/while/do-while steps

[jawwad-ali]

Problem

IfThenStep, WhileStep, and DoWhileStep validate() confirm that condition is present but never that it is a string.

At run time execute() feeds condition to evaluate_condition():

def evaluate_expression(template, context):
    if not isinstance(template, str):
        return template   # non-string returned as-is
    ...

def evaluate_condition(condition, context):
    result = evaluate_expression(condition, context)
    ...
    return bool(result)

So a non-string condition is returned unchanged and bool()-coerced. A list/dict/number authoring mistake silently resolves to a truthiness instead of erroring:

• condition: [1, 2] → bool([1, 2]) → always True → if-branch always taken / while-loop spins to max_iterations.
• condition: {} → always False, etc.

No error is reported, so the mistake is invisible.

Fix

Reject a present-but-non-string condition in each of the three steps' validate(), mirroring the existing prompt/shell/command 'must be a string' guards. "true"/"false" and expressions like "{{ inputs.flag }}" are strings, so they remain valid — no behaviour change for correct workflows.

Verification

• New parametrized tests ([list, dict, int, bool]) across all three step classes: fail before the guard (12 failures — the non-string conditions pass validation), pass after.
• test_validate_accepts_string_condition confirms "true"/"false"/"{{ ... }}" still validate.
• Full TestIfThenStep/TestWhileStep/TestDoWhileStep: 53 passed.
• ruff check clean on all changed files.

---

AI-assisted: authored with Claude Code. I traced the runtime path (evaluate_condition → bool()), confirmed the silent-coercion on main, and verified the guards fail-before/pass-after.

[Copilot]

Pull request overview

Adds validation to prevent non-string workflow conditions from being silently truthiness-coerced.

Changes:

• Validates conditions for if, while, and do-while steps.
• Adds parameterized regression tests for invalid condition types.

Show a summary per file

File	Description
if_then/__init__.py	Rejects non-string if conditions.
while_loop/__init__.py	Rejects non-string while conditions.
do_while/__init__.py	Rejects non-string do-while conditions.
tests/test_workflows.py	Covers invalid and valid condition values.

Review details

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• Files reviewed: 4/4 changed files
• Comments generated: 4
• Review effort level: Medium

[mnriem]

Please address Copilot feedback

[jawwad-ali]

Good catch — fixed in 6a78c02. You're right that evaluate_condition() always returns a bool; the pass-through happens one level down in evaluate_expression(), which evaluate_condition() calls before applying bool(). I reworded all four sites (the if/while/do-while guards and the mirror test comment) to name the two stages explicitly:

execute() feeds 'condition' to evaluate_condition(), which first delegates to evaluate_expression() -- that returns a non-string unchanged -- and then coerces the result with bool().

Comments only; no behaviour change. ruff@0.15.0 clean and the condition tests still pass (28).