Debug With an Agent: Reproduce, Fix, and Add the Regression Test

"""Your debugging agent. It reproduces a failure, asks a model for a fix, verifies the fix against the whole
suite, loops until green, and then insists on a regression test that fails on the old code, the discipline
that stops the same bug coming back."""
import harness


def extract_code(reply):
    """Pull code out of a model reply: the first ``` fenced block (dropping an optional python tag), or the
    whole reply stripped when there is no fence."""
    # TODO (Step 1): first ``` fenced block (drop a leading 'python'), else the whole reply stripped.
    raise NotImplementedError("Step 1: write extract_code()")


def reproduce(buggy_src, tests_src):
    """Run the suite against the buggy code and return the failure. Raise if nothing fails: you cannot fix a
    bug you cannot reproduce."""
    # TODO (Step 1): run the suite on the buggy code; return the failure, raise ValueError if nothing fails.
    raise NotImplementedError("Step 1: write reproduce()")


def propose_fix(buggy_src, failure, ask=harness.ask, feedback=""):
    """Ask the model to fix the code given the failing tests. Fold in feedback from a previous attempt.
    Return the extracted code."""
    raise NotImplementedError("propose_fix() arrives in Step 2")


def verify(fixed_src, tests_src):
    """Run the whole suite against a candidate fix. Returns {"passed", "failed", "total", "error", "ok"}
    where ok is True only when every test passes."""
    raise NotImplementedError("verify() arrives in Step 3")


def debug(buggy_src, tests_src, ask=harness.ask, max_iters=3):
    """Reproduce, then propose a fix and verify it, feeding the still-failing tests back until the suite is
    green or the budget runs out. Returns {"code", "fixed", "iters", "history"}."""
    raise NotImplementedError("debug() arrives in Step 4")


def guards_bug(test_src, buggy_src, fixed_src):
    """Does this test actually guard the bug? A real regression test fails on the buggy code and passes on
    the fixed code. Returns True only when both hold."""
    raise NotImplementedError("guards_bug() arrives in Step 5")


def add_regression_test(buggy_src, fixed_src, ask=harness.ask):
    """Ask the model for a new test_* that captures the bug, then keep it only if it actually guards the bug
    (fails on the old code, passes on the new). Returns {"test", "guards"}."""
    raise NotImplementedError("add_regression_test() arrives in Step 5")