[3/N] feat(runway): add VCS extension interface, mock, and noop impl

runway/extension/BUILD.bazel

@@ -0,0 +1,8 @@
+load("@rules_go//go:def.bzl", "go_library")
+
+go_library(
+    name = "extension",
+    srcs = ["extension.go"],
+    importpath = "github.com/uber/submitqueue/runway/extension",
+    visibility = ["//visibility:public"],
+)

runway/extension/extension.go

@@ -0,0 +1,16 @@
+// Copyright (c) 2025 Uber Technologies, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package extension holds Runway-specific extension implementations.
+package extension

runway/extension/vcs/BUILD.bazel

@@ -0,0 +1,9 @@
+load("@rules_go//go:def.bzl", "go_library")
+
+go_library(
+    name = "vcs",
+    srcs = ["vcs.go"],
+    importpath = "github.com/uber/submitqueue/runway/extension/vcs",
+    visibility = ["//visibility:public"],
+    deps = ["//runway/entity"],
+)

runway/extension/vcs/mock/BUILD.bazel

@@ -0,0 +1,13 @@
+load("@rules_go//go:def.bzl", "go_library")
+
+go_library(
+    name = "mock",
+    srcs = ["vcs_mock.go"],
+    importpath = "github.com/uber/submitqueue/runway/extension/vcs/mock",
+    visibility = ["//visibility:public"],
+    deps = [
+        "//runway/entity",
+        "//runway/extension/vcs",
+        "@org_uber_go_mock//gomock",
+    ],
+)

runway/extension/vcs/noop/BUILD.bazel

@@ -0,0 +1,25 @@
+load("@rules_go//go:def.bzl", "go_library", "go_test")
+
+go_library(
+    name = "noop",
+    srcs = ["noop.go"],
+    importpath = "github.com/uber/submitqueue/runway/extension/vcs/noop",
+    visibility = ["//visibility:public"],
+    deps = [
+        "//runway/entity",
+        "//runway/extension/vcs",
+    ],
+)
+
+go_test(
+    name = "noop_test",
+    srcs = ["noop_test.go"],
+    embed = [":noop"],
+    deps = [
+        "//entity/change",
+        "//entity/mergestrategy",
+        "//runway/entity",
+        "@com_github_stretchr_testify//assert",
+        "@com_github_stretchr_testify//require",
+    ],
+)

runway/extension/vcs/noop/noop.go

@@ -0,0 +1,56 @@
+// Copyright (c) 2025 Uber Technologies, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package noop provides a VCS implementation that reports every check as
+// mergeable and every land as committed with synthetic commit SHAs. It is
+// intended for wiring and tests only, never production.
+package noop
+
+import (
+	"context"
+	"fmt"
+	"sync/atomic"
+
+	"github.com/uber/submitqueue/runway/entity"
+	"github.com/uber/submitqueue/runway/extension/vcs"
+)
+
+type noopVCS struct {
+	counter atomic.Uint64
+}
+
+// New returns a vcs.VCS that defaults to success for all operations.
+func New() vcs.VCS {
+	return &noopVCS{}
+}
+
+func (n *noopVCS) CheckMergeability(_ context.Context, check entity.Check) ([]entity.MergeabilityResult, error) {
+	results := make([]entity.MergeabilityResult, len(check.Changes))
+	for i, c := range check.Changes {
+		results[i] = entity.MergeabilityResult{Change: c, Mergeable: true}
+	}
+	return results, nil
+}
+
+func (n *noopVCS) Land(_ context.Context, job entity.Job) ([]entity.Outcome, error) {
+	outcomes := make([]entity.Outcome, len(job.Items))
+	for i, item := range job.Items {
+		outcomes[i] = entity.Outcome{
+			RequestID:  item.RequestID,
+			Change:     item.Change,
+			CommitSHAs: []string{fmt.Sprintf("noop-%d", n.counter.Add(1))},
+		}
+	}
+	return outcomes, nil
+}

runway/extension/vcs/noop/noop_test.go

@@ -0,0 +1,105 @@
+// Copyright (c) 2025 Uber Technologies, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package noop
+
+import (
+	"context"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"github.com/uber/submitqueue/entity/change"
+	"github.com/uber/submitqueue/entity/mergestrategy"
+	"github.com/uber/submitqueue/runway/entity"
+)
+
+func TestNoopVCS_CheckMergeability(t *testing.T) {
+	v := New()
+	check := entity.Check{
+		Queue:        "q1",
+		RequestID:    "q1/1",
+		Repo:         "uber/repo",
+		TargetBranch: "main",
+		Changes: []change.Change{
+			{URIs: []string{"github://uber/repo/pull/1/aaaa"}},
+			{URIs: []string{"github://uber/repo/pull/2/bbbb"}},
+		},
+		Strategy: mergestrategy.MergeStrategyRebase,
+	}
+
+	results, err := v.CheckMergeability(context.Background(), check)
+	require.NoError(t, err)
+	require.Len(t, results, 2)
+
+	for _, r := range results {
+		assert.True(t, r.Mergeable)
+		assert.Empty(t, r.Reason)
+	}
+}
+
+func TestNoopVCS_CheckMergeability_Empty(t *testing.T) {
+	v := New()
+	check := entity.Check{Changes: []change.Change{}}
+
+	results, err := v.CheckMergeability(context.Background(), check)
+	require.NoError(t, err)
+	assert.Empty(t, results)
+}
+
+func TestNoopVCS_Land(t *testing.T) {
+	v := New()
+	job := entity.Job{
+		ID:           "job-1",
+		BatchID:      "q1/batch/1",
+		Queue:        "q1",
+		Repo:         "uber/repo",
+		TargetBranch: "main",
+		Items: []entity.JobItem{
+			{
+				RequestID: "q1/10",
+				Change:    change.Change{URIs: []string{"github://uber/repo/pull/10/aaaa"}},
+				Strategy:  mergestrategy.MergeStrategyRebase,
+			},
+			{
+				RequestID: "q1/11",
+				Change:    change.Change{URIs: []string{"github://uber/repo/pull/11/bbbb"}},
+				Strategy:  mergestrategy.MergeStrategySquashRebase,
+			},
+		},
+	}
+
+	outcomes, err := v.Land(context.Background(), job)
+	require.NoError(t, err)
+	require.Len(t, outcomes, 2)
+
+	assert.Equal(t, "q1/10", outcomes[0].RequestID)
+	assert.Equal(t, "q1/11", outcomes[1].RequestID)
+	assert.False(t, outcomes[0].AlreadyExisted)
+	assert.False(t, outcomes[1].AlreadyExisted)
+
+	// Each outcome has a unique commit SHA.
+	assert.Len(t, outcomes[0].CommitSHAs, 1)
+	assert.Len(t, outcomes[1].CommitSHAs, 1)
+	assert.NotEqual(t, outcomes[0].CommitSHAs[0], outcomes[1].CommitSHAs[0])
+}
+
+func TestNoopVCS_Land_Empty(t *testing.T) {
+	v := New()
+	job := entity.Job{Items: []entity.JobItem{}}
+
+	outcomes, err := v.Land(context.Background(), job)
+	require.NoError(t, err)
+	assert.Empty(t, outcomes)
+}