Module contract_walk 

Shared recursive contract directory walker.

Multiple pv subcommands need to load every YAML contract under a directory tree (including subdirectories like contracts/aprender/, contracts/trueno/, contracts/patterns/). This module provides the canonical walker so commands agree on what counts as a contract and which sidecar files to skip.

PVL-1 (PMAT-1099): a corpus with ZERO contracts is REFUSED, never reported. Measured before this change (PV-LEAN-AUDIT-001, 2026-09-10): pv lint /nonexistent-path exited 0 with Result: PASS over 0 contracts, and pv proof-status <empty dir> printed Proof Status (0 contracts) at exit 0 — a gate that measures nothing and reports PASS. collect_corpus is the entry point every reporting subcommand uses: it returns ZeroContracts (exit ZERO_CONTRACTS_EXIT) for an empty or missing directory, and treats a single .yaml file as a one-contract corpus so pv <cmd> <file> reports that file instead of walking nothing.

ONE definition of “empty”. The set of contract files is the one pv lint walks — provable_contracts::lint::collect_yaml_files (the is_contract_yaml rule plus the skipped sidecar directories) — so no two commands can disagree on what is there. A contract file that fails to parse is NOT “no contract”: it was measured, and it failed (ParseErrors, exit 1, every file named). The second review quorum on #3093 measured proof-status and lint --diff refusing an unparsable-only directory as “0 contracts” (exit 2) while lint failed the same directory with contracts: 1, errors: 1 (exit 1); this walker’s old private rule also skipped every *playbook* stem, and the corpus holds real contracts named that way.

Structs

ParseErrors

Contract files under path that failed to parse: measured, and failed (exit 1) — never a silent skip, never “0 contracts”.

ZeroContracts

The corpus under path holds no contract (after filter, when set).

Constants

ZERO_CONTRACTS_EXIT

Exit status of a refused empty corpus.

Functions

collect_contracts

Walk dir and collect every PARSEABLE contract, dropping the rest.

collect_corpus

Load the corpus at path and refuse an empty one.

exit_code_for

Exit status for a dispatch error: ZERO_CONTRACTS_EXIT for a refused empty corpus, 1 for everything else (a parse failure included).

has_contract_files

Is there at least one contract file under path? The one definition of a non-empty corpus, answered WITHOUT parsing (diff mode asks this before it says “nothing changed”). A file path is a one-contract corpus.

require_contracts

Refuse an empty corpus: Err(ZeroContracts) when corpus is empty.

verdict_for

The verdict class pv prints before an error, in PVL-001 §0’s vocabulary: decline (exit 2, nothing measured), reject (exit 1, measured and failed), error (anything else). One definition, so the word and the exit code cannot drift apart — ONT-001 §5 ONT-1 asserts both halves of the line.

walk_contracts

Walk dir recursively with pv lint’s file rule: every contract file is parsed into out as (stem, contract), or recorded in errors as (file, error). Nothing is dropped.