prowgen: add skip_branches support to ProwgenOverrides

pkg/api/types.go

@@ -881,6 +881,14 @@ type TestStepConfiguration struct {
 	// Only applicable to presubmits; postsubmits always run on every merge.
 	SkipIfOnlyChanged string `json:"skip_if_only_changed,omitempty"`
 
+	// SkipBranches is a list of branch name regex patterns. Branches matching
+	// any of these patterns will be excluded from running this presubmit job.
+	// This maps directly to the upstream Prow Brancher.SkipBranches field and
+	// is useful to prevent feature branch inheritance (e.g. preventing a
+	// presubmit configured for "main" from also running on "main-*" branches).
+	// Only applicable to presubmit tests.
+	SkipBranches []string `json:"skip_branches,omitempty"`
+
 	// PipelineSkipIfOnlyChanged is a regex that will result in the test being skipped in second
 	// stage of the pipeline run if all changed files match that regex.
 	PipelineSkipIfOnlyChanged string `json:"pipeline_skip_if_only_changed,omitempty"`

pkg/prowgen/prowgen.go

@@ -225,6 +225,7 @@ func handlePresubmit(g *prowJobBaseBuilder, element cioperatorapi.TestStepConfig
 		options.Capabilities = element.Capabilities
 		options.runIfChanged = element.RunIfChanged
 		options.skipIfOnlyChanged = element.SkipIfOnlyChanged
+		options.skipBranches = element.SkipBranches
 		options.defaultDisable = element.AlwaysRun != nil && !*element.AlwaysRun
 		options.optional = element.Optional
 		options.disableRehearsal = disableRehearsal
@@ -244,6 +245,7 @@ type generatePresubmitOptions struct {
 	Capabilities              []string
 	runIfChanged              string
 	skipIfOnlyChanged         string
+	skipBranches              []string
 	defaultDisable            bool
 	optional                  bool
 	disableRehearsal          bool
@@ -307,7 +309,10 @@ func generatePresubmitForTest(jobBaseBuilder *prowJobBaseBuilder, name string, i
 	pj := &prowconfig.Presubmit{
 		JobBase:   base,
 		AlwaysRun: opts.shouldAlwaysRun(),
-		Brancher:  prowconfig.Brancher{Branches: sets.List(sets.New[string](jc.ExactlyBranch(info.Branch), jc.FeatureBranch(info.Branch)))},
+		Brancher: prowconfig.Brancher{
+			Branches:     sets.List(sets.New[string](jc.ExactlyBranch(info.Branch), jc.FeatureBranch(info.Branch))),
+			SkipBranches: opts.skipBranches,
+		},
 		Reporter: prowconfig.Reporter{
 			Context: fmt.Sprintf("ci/prow/%s", shortName),
 		},

pkg/prowgen/prowgen_test.go

@@ -240,6 +240,14 @@ func TestGeneratePresubmitForTest(t *testing.T) {
 				options.maxConcurrency = 4
 			},
 		},
+		{
+			description: "presubmit with skip_branches",
+			test:        "testname",
+			repoInfo:    &ciop.Metadata{Org: "org", Repo: "repo", Branch: "branch"},
+			generateOption: func(options *generatePresubmitOptions) {
+				options.skipBranches = []string{"^branch-foo$", "^branch-bar$"}
+			},
+		},
 	}
 	for _, tc := range tests {
 		t.Run(tc.description, func(t *testing.T) {
@@ -935,8 +943,21 @@ func TestGenerateJobs(t *testing.T) {
 				Branch: "branch",
 			},
 		},
+		{
+			id:   "presubmit with per-test skip_branches",
+			keep: true,
+			config: &ciop.ReleaseBuildConfiguration{
+				Tests: []ciop.TestStepConfiguration{
+					{As: "derTest", SkipBranches: []string{"^branch-foo$", "^branch-bar$"}, ContainerTestConfiguration: &ciop.ContainerTestConfiguration{From: "from"}},
+				},
+			},
+			repoInfo: &ciop.Metadata{
+				Org:    "organization",
+				Repo:   "repository",
+				Branch: "branch",
+			},
+		},
 	}
-
 	for _, tc := range tests {
 		t.Run(tc.id, func(t *testing.T) {
 			jobConfig, err := GenerateJobs(tc.config, tc.repoInfo)

pkg/prowgen/testdata/zz_fixture_TestGenerateJobs_presubmit_with_per-test_skip_branches.yaml

@@ -0,0 +1,58 @@
+presubmits:
+  organization/repository:
+  - agent: kubernetes
+    always_run: true
+    branches:
+    - ^branch$
+    - ^branch-
+    context: ci/prow/derTest
+    decorate: true
+    decoration_config:
+      skip_cloning: true
+    labels:
+      pj-rehearse.openshift.io/can-be-rehearsed: "true"
+    name: pull-ci-organization-repository-branch-derTest
+    rerun_command: /test derTest
+    skip_branches:
+    - ^branch-foo$
+    - ^branch-bar$
+    spec:
+      containers:
+      - args:
+        - --gcs-upload-secret=/secrets/gcs/service-account.json
+        - --image-import-pull-secret=/etc/pull-secret/.dockerconfigjson
+        - --report-credentials-file=/etc/report/credentials
+        - --target=derTest
+        command:
+        - ci-operator
+        image: quay-proxy.ci.openshift.org/openshift/ci:ci_ci-operator_latest
+        imagePullPolicy: Always
+        name: ""
+        resources:
+          requests:
+            cpu: 10m
+        volumeMounts:
+        - mountPath: /secrets/gcs
+          name: gcs-credentials
+          readOnly: true
+        - mountPath: /secrets/manifest-tool
+          name: manifest-tool-local-pusher
+          readOnly: true
+        - mountPath: /etc/pull-secret
+          name: pull-secret
+          readOnly: true
+        - mountPath: /etc/report
+          name: result-aggregator
+          readOnly: true
+      serviceAccountName: ci-operator
+      volumes:
+      - name: manifest-tool-local-pusher
+        secret:
+          secretName: manifest-tool-local-pusher
+      - name: pull-secret
+        secret:
+          secretName: registry-pull-credentials
+      - name: result-aggregator
+        secret:
+          secretName: result-aggregator
+    trigger: (?m)^/test( | .* )derTest,?($|\s.*)

pkg/prowgen/testdata/zz_fixture_TestGeneratePresubmitForTest_presubmit_with_skip_branches.yaml

@@ -0,0 +1,17 @@
+agent: kubernetes
+always_run: true
+branches:
+- ^branch$
+- ^branch-
+context: ci/prow/testname
+decorate: true
+decoration_config:
+  skip_cloning: true
+labels:
+  pj-rehearse.openshift.io/can-be-rehearsed: "true"
+name: pull-ci-org-repo-branch-testname
+rerun_command: /test testname
+skip_branches:
+- ^branch-foo$
+- ^branch-bar$
+trigger: (?m)^/test( | .* )testname,?($|\s.*)