Restructure refimpl into go-lang and python subdirectories

Move Go reference implementation to refimpl/go-lang/ and add new Python reference implementation in refimpl/python/. Update build.sh with renamed draft and simplified tool paths. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
2026-02-25 23:11:55 +01:00
parent ff795c72e6
commit bbf557e54b
52 changed files with 3972 additions and 341 deletions
--- a/refimpl/python/ect/dag.py
+++ b/refimpl/python/ect/dag.py
@@ -0,0 +1,97 @@
+"""DAG validation per Section 6."""
+
+from __future__ import annotations
+
+from abc import ABC, abstractmethod
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from ect.types import Payload
+
+from ect.validate import DEFAULT_MAX_PAR_LENGTH
+
+DEFAULT_CLOCK_SKEW_TOLERANCE = 30
+DEFAULT_MAX_ANCESTOR_LIMIT = 10000
+
+
+class ECTStore(ABC):
+    """Lookup of ECTs by task ID for DAG validation."""
+
+    @abstractmethod
+    def get_by_tid(self, tid: str) -> "Payload | None":
+        pass
+
+    @abstractmethod
+    def contains(self, tid: str, wid: str) -> bool:
+        pass
+
+
+class DAGConfig:
+    def __init__(
+        self,
+        clock_skew_tolerance: int = DEFAULT_CLOCK_SKEW_TOLERANCE,
+        max_ancestor_limit: int = DEFAULT_MAX_ANCESTOR_LIMIT,
+        max_par_length: int = 0,
+    ):
+        self.clock_skew_tolerance = clock_skew_tolerance or DEFAULT_CLOCK_SKEW_TOLERANCE
+        self.max_ancestor_limit = max_ancestor_limit or DEFAULT_MAX_ANCESTOR_LIMIT
+        self.max_par_length = max_par_length or 0
+
+
+def default_dag_config() -> DAGConfig:
+    return DAGConfig()
+
+
+def _has_cycle(
+    target_tid: str,
+    parent_ids: list[str],
+    store: ECTStore,
+    visited: set[str],
+    max_depth: int,
+) -> bool:
+    if len(visited) >= max_depth:
+        return True
+    for parent_id in parent_ids:
+        if parent_id == target_tid:
+            return True
+        if parent_id in visited:
+            continue
+        visited.add(parent_id)
+        parent = store.get_by_tid(parent_id)
+        if parent is not None:
+            if _has_cycle(target_tid, parent.par, store, visited, max_depth):
+                return True
+    return False
+
+
+def validate_dag(
+    payload: "Payload",
+    store: ECTStore,
+    cfg: DAGConfig,
+) -> None:
+    """Section 6.2: uniqueness (by jti), parent existence, temporal ordering, acyclicity, parent policy."""
+    if cfg.max_par_length > 0 and len(payload.par) > cfg.max_par_length:
+        raise ValueError("ect: par exceeds max length")
+    if store.contains(payload.jti, payload.wid or ""):
+        raise ValueError(f"ect: task ID (jti) already exists: {payload.jti}")
+    from ect.types import POL_DECISION_REJECTED, POL_DECISION_PENDING_HUMAN_REVIEW
+
+    for parent_id in payload.par:
+        parent = store.get_by_tid(parent_id)
+        if parent is None:
+            raise ValueError(f"ect: parent task not found: {parent_id}")
+        if parent.iat >= payload.iat + cfg.clock_skew_tolerance:
+            raise ValueError(f"ect: parent task not earlier than current: {parent_id}")
+
+    visited: set[str] = set()
+    if _has_cycle(payload.jti, payload.par, store, visited, cfg.max_ancestor_limit):
+        raise ValueError("ect: circular dependency or depth limit exceeded")
+
+    # Parent policy decision: only when parent has policy claims per spec
+    for parent_id in payload.par:
+        parent = store.get_by_tid(parent_id)
+        if parent and parent.has_policy_claims() and parent.pol_decision in (POL_DECISION_REJECTED, POL_DECISION_PENDING_HUMAN_REVIEW):
+            if not payload.compensation_required():
+                raise ValueError(
+                    "ect: parent has non-approved pol_decision; current ECT must be compensation/remediation or have ext.compensation_required true"
+                )