fix(bot): handling of duplicate check suites

bot/kodiak/evaluation.py

@@ -1,6 +1,9 @@
+from __future__ import annotations
+
 import asyncio
 import textwrap
 from collections import defaultdict
+from collections.abc import Iterable
 from dataclasses import dataclass
 from typing import Dict, List, MutableMapping, Optional, Sequence, Set, Union
 
@@ -260,6 +263,13 @@ def review_status(reviews: List[PRReview]) -> PRReviewState:
     return status
 
 
+def deduplicate_check_runs(check_runs: Iterable[CheckRun]) -> List[CheckRun]:
+    check_run_map = dict()
+    for check_run in check_runs:
+        check_run_map[check_run.name] = check_run
+    return list(check_run_map.values())
+
+
 class PRAPI(Protocol):
     async def dequeue(self) -> None:
         ...
@@ -882,7 +892,8 @@ async def set_status(msg: str, markdown_content: Optional[str] = None) -> None:
                 else:
                     assert status_context.state == StatusState.SUCCESS
                     passing_contexts.append(status_context.context)
-            for check_run in check_runs:
+
+            for check_run in deduplicate_check_runs(check_runs):
                 if (
                     check_run.name in config.merge.dont_wait_on_status_checks
                     and check_run.conclusion in (None, CheckConclusionState.NEUTRAL)

bot/kodiak/test_evaluation.py

@@ -282,8 +282,12 @@ def create_context() -> StatusContext:
     return StatusContext(context="ci/api", state=StatusState.SUCCESS)
 
 
-def create_check_run() -> CheckRun:
-    return CheckRun(name="WIP (beta)", conclusion=CheckConclusionState.SUCCESS)
+def create_check_run(
+    *,
+    name: str = "WIP (beta)",
+    conclusion: CheckConclusionState = CheckConclusionState.SUCCESS,
+) -> CheckRun:
+    return CheckRun(name=name, conclusion=conclusion)
 
 
 def create_review_request() -> PRReviewRequest:

bot/kodiak/tests/evaluation/test_check_runs.py

@@ -1,8 +1,13 @@
+"""
+Tests for flows that depend on status checks or check_runs.
+"""
 import pytest
 
 from kodiak.errors import PollForever, RetryForSkippableChecks
-from kodiak.queries import CheckConclusionState, MergeStateStatus, StatusState
+from kodiak.queries import StatusState
 from kodiak.test_evaluation import (
+    CheckConclusionState,
+    MergeStateStatus,
     create_api,
     create_branch_protection,
     create_check_run,
@@ -562,3 +567,38 @@ async def test_mergeable_update_always_no_require_automerge_label_missing_label(
     assert api.queue_for_merge.call_count == 0
     assert api.merge.call_count == 0
     assert api.dequeue.call_count == 0
+
+
+@pytest.mark.asyncio
+async def test_duplicate_check_suites() -> None:
+    """
+    Kodiak should only consider the most recent check run when evaluating a PR
+    for merging.
+
+    Regression test.
+    """
+    api = create_api()
+    pull_request = create_pull_request()
+    pull_request.mergeStateStatus = MergeStateStatus.BEHIND
+    branch_protection = create_branch_protection()
+    branch_protection.requiresStatusChecks = True
+    branch_protection.requiredStatusCheckContexts = ["Pre-merge checks"]
+    mergeable = create_mergeable()
+    await mergeable(
+        api=api,
+        pull_request=pull_request,
+        branch_protection=branch_protection,
+        check_runs=[
+            create_check_run(
+                name="Pre-merge checks", conclusion=CheckConclusionState.NEUTRAL
+            ),
+            create_check_run(
+                name="Pre-merge checks", conclusion=CheckConclusionState.FAILURE
+            ),
+            create_check_run(
+                name="Pre-merge checks", conclusion=CheckConclusionState.SUCCESS
+            ),
+        ],
+    )
+    assert "enqueued for merge" in api.set_status.calls[0]["msg"]
+    assert api.queue_for_merge.call_count == 1