cirrus.yml: implement skips based on source changes

We do not have to test everything for each PR, we can know based on the
source if we changed (i.e. machine code) and only run the tests then.

This implements it as skip conditions, due to the nature of yaml files
we unfortunately cannot deduplicate everything, i.e. the is PR check and
danger files apply to everything but as skip is only a single yaml
string we cannot deduplicate parts of that string. If anyone knows a way
to achieve this I like to hear it.

For now I implemented this for int, system, bud and machine tests. Once
we are more comfortable with this I plan on adding it to other tests as
well.

This will replace the current _bail_if_test_can_be_skipped logic as it
covers more, marks tasks actually skipped in the github UI and works
even for the windows/macos machine tests.

Signed-off-by: Paul Holzinger <pholzing@redhat.com>

.cirrus.yml

@@ -639,6 +639,15 @@ local_integration_test_task: &local_integration_test_task
     alias: local_integration_test
     # Docs: ./contrib/cirrus/CIModes.md
     only_if: *not_tag_branch_build_docs_machine
+    # skip when: - it is a PR (we never want to skip on nightly tests); and
+    #            - no danger files are changed; and
+    #            - when no int test code is changed; and
+    #            - NOT (source code is changed AND NOT only test files)
+    skip: &skip_int_test >-
+        $CIRRUS_PR != '' &&
+        !changesInclude('.cirrus.yml', 'Makefile', 'contrib/cirrus/**', 'vendor/**', 'hack/**', 'version/rawversion/*') &&
+        !changesInclude('test/e2e/**', 'test/utils/**') &&
+        !(changesInclude('**/*.go', '**/*.c') && !changesIncludeOnly('test/**', 'pkg/machine/e2e/**'))
     depends_on: *build
     matrix: *platform_axis
     # integration tests scale well with cpu as they are parallelized
@@ -680,6 +689,7 @@ container_integration_test_task:
     alias: container_integration_test
     # Docs: ./contrib/cirrus/CIModes.md
     only_if: *not_tag_branch_build_docs_machine
+    skip: *skip_int_test
     depends_on: *build
     matrix: &fedora_vm_axis
         - env:
@@ -708,6 +718,7 @@ rootless_integration_test_task:
     alias: rootless_integration_test
     # Docs: ./contrib/cirrus/CIModes.md
     only_if: *not_tag_branch_build_docs_machine
+    skip: *skip_int_test
     depends_on: *build
     matrix: *platform_axis
     gce_instance: *fastvm
@@ -731,6 +742,13 @@ podman_machine_task:
          $CIRRUS_CHANGE_TITLE !=~ '.*CI:DOCS.*' &&
          $CIRRUS_CHANGE_TITLE !=~ '.*CI:BUILD.*'
         ) || $CIRRUS_CRON == "main"
+    # skip when: - it is a PR (we never want to skip on nightly tests); and
+    #            - no danger files are changed; and
+    #            - no machine code files are changed
+    skip: &skip_machine_test >-
+        $CIRRUS_PR != '' &&
+        !changesInclude('.cirrus.yml', 'Makefile', 'contrib/cirrus/**', 'vendor/**', 'hack/**', 'version/rawversion/*') &&
+        !changesInclude('cmd/podman/machine/**', 'pkg/machine/**', '**/*machine*.go')
     depends_on: *build
     ec2_instance:
         image: "${VM_IMAGE_NAME}"
@@ -752,6 +770,7 @@ podman_machine_aarch64_task:
     name: *std_name_fmt
     alias: podman_machine_aarch64
     only_if: *machine_cron_not_tag_build_docs
+    skip: *skip_machine_test
     depends_on: *build
     ec2_instance:
         <<: *standard_build_ec2_aarch64
@@ -773,6 +792,7 @@ podman_machine_windows_task:
     # Only run for non-docs/copr PRs and non-release branch builds
     # and never for tags.  Docs: ./contrib/cirrus/CIModes.md
     only_if: *machine_cron_not_tag_build_docs
+    skip: *skip_machine_test
     depends_on: *build
     ec2_instance:
         <<: *windows
@@ -797,6 +817,7 @@ podman_machine_mac_task:
     name: *std_name_fmt
     alias: podman_machine_mac
     only_if: *machine_cron_not_tag_build_docs
+    skip: *skip_machine_test
     depends_on: *build
     persistent_worker: *mac_pw
     env:
@@ -849,6 +870,15 @@ local_system_test_task: &local_system_test_task
         $CIRRUS_CHANGE_TITLE !=~ '.*CI:DOCS.*' &&
         $CIRRUS_CHANGE_TITLE !=~ '.*CI:BUILD.*' &&
         $CIRRUS_CHANGE_TITLE !=~ '.*CI:MACHINE.*'
+    # skip when: - it is a PR (we never want to skip on nightly tests); and
+    #            - no danger files are changed; and
+    #            - no system test code is changed; and
+    #            - NOT (source code is changed AND not only test files)
+    skip: &skip_system_test >-
+        $CIRRUS_PR != '' &&
+        !changesInclude('.cirrus.yml', 'Makefile', 'contrib/cirrus/**', 'vendor/**', 'hack/**', 'version/rawversion/*') &&
+        !changesInclude('test/system/**') &&
+        !(changesInclude('**/*.go', '**/*.c') && !changesIncludeOnly('test/**', 'pkg/machine/e2e/**'))
     depends_on: *build
     matrix: *platform_axis
     gce_instance: *standardvm
@@ -866,6 +896,7 @@ local_system_test_aarch64_task: &local_system_test_task_aarch64
     # Don't create task for tags, or if using [CI:DOCS], [CI:BUILD]
     # Docs: ./contrib/cirrus/CIModes.md
     only_if: *not_tag_magic
+    skip: *skip_system_test
     depends_on: *build
     persistent_worker: *mac_pw
     ec2_instance: *standard_build_ec2_aarch64
@@ -917,6 +948,7 @@ rootless_system_test_task:
     alias: rootless_system_test
     # Docs: ./contrib/cirrus/CIModes.md
     only_if: *not_tag_magic
+    skip: *skip_system_test
     depends_on: *build
     matrix: *platform_axis
     gce_instance: *standardvm
@@ -968,6 +1000,13 @@ buildah_bud_test_task:
     alias: buildah_bud_test
     # Docs: ./contrib/cirrus/CIModes.md
     only_if: *not_tag_magic
+    # skip when: - it is a PR (we never want to skip on nightly tests); and
+    #            - no danger files are changed; and
+    #            - no build source files are changed and no bud tests
+    skip: >-
+        $CIRRUS_PR != '' &&
+        !changesInclude('.cirrus.yml', 'Makefile', 'contrib/cirrus/**', 'vendor/**', 'hack/**', 'version/rawversion/*') &&
+        !changesInclude('**/*build*.go', 'test/buildah-bud/**')
     depends_on: *build
     env:
         <<: *stdenvars

contrib/cirrus/cirrus_yaml_test.py

@@ -60,6 +60,21 @@ class TestDependsOn(TestCaseBase):
                 msg=('No success aggregation task depends_on "{0}"'.format(task_name))
                 self.assertIn(task_name, success_deps, msg=msg)
 
+    def test_skips(self):
+        """2024-06 PR#23030: ugly but necessary duplication in skip conditions. Prevent typos or unwanted changes."""
+        beginning = "$CIRRUS_PR != '' && !changesInclude('.cirrus.yml', 'Makefile', 'contrib/cirrus/**', 'vendor/**', 'hack/**', 'version/rawversion/*') && "
+        real_source_changes = " && !(changesInclude('**/*.go', '**/*.c') && !changesIncludeOnly('test/**', 'pkg/machine/e2e/**'))"
+
+        for task_name in self.ALL_TASK_NAMES:
+            task = self.CIRRUS_YAML[task_name + '_task']
+            if 'skip' in task:
+                skip = task['skip']
+                if 'changesInclude' in skip:
+                    msg = ('{0}: invalid skip'.format(task_name))
+                    self.assertEqual(skip[:len(beginning)], beginning, msg=msg+": beginning part is wrong")
+                    if 'changesIncludeOnly' in skip:
+                        self.assertEqual(skip[len(skip)-len(real_source_changes):], real_source_changes, msg=msg+": changesIncludeOnly() part is wrong")
+
     def not_task(self):
         """Ensure no task is named 'task'"""
         self.assertNotIn('task', self.ALL_TASK_NAMES)