ci: [BACKPORT] Setting up conditional CI runs depending on PR comment trigger

.yamato/_triggers.yml

@@ -11,10 +11,13 @@
 # TRIGGER PATTERNS-------------------------------------------------------------------
   # Pull Request:
     # This test validates Standards, Package tests, Project tests and Desktop standalone tests to ensure that main platforms are covered
-    # Triggers on PRs to develop, develop, and release branches
-    # Focuses on critical validation paths that we should validate before merging PRs
-    # Cancels previous runs on new commits
-    # Excludes draft PRs
+    # Focuses on critical validation paths that we should validate before merging PRs. It also cancels previous runs on new commits
+    # By default it's triggered if
+      # 1) PR targets develop, develop-2.0.0 or release branches
+      # 2) PR is not a draft
+      # 3) PR changes files in package or testproject folders (doesn't run on for example DOCS only changes)
+
+    # Note that in other cases you can trigger it by writing a comment "/ci ngo" in the PR thread
 
   # Nightly:
     # This test validates same subset as pull_request_trigger with addition of mobile/console tests and webgl builds
@@ -38,6 +41,7 @@
 
 #-----------------------------------------------------------------------------------
 
+
 # Run all relevant tasks when a pull request targeting the develop or release branch is created or updated.
 # In order to have better coverage we run desktop standalone tests with different configurations which allows to mostly cover for different platforms, scripting backends and editor versions.
 # Since standards job is a part of initial checks it's not present as direct dependency here
@@ -61,15 +65,18 @@ pull_request_trigger:
     # Coverage on other standalone machines is present in Nightly job so it's enough to not run all of them for PRs
     - .yamato/desktop-standalone-tests.yml#desktop_standalone_test_testproject_ubuntu_il2cpp_2022.3
   triggers:
+    # Note that PR tests will run ONLY if we are changing package/sample code. If changes are let's say docs only no tests will be triggered
+    # TODO: consider setting up and running tests from Examples/
+    # TODO: or docs only changes are spelling/link check
+    expression: |-
+      pull_request.comment eq "ngo" OR
+      ((pull_request.target eq "develop" OR
+      pull_request.target eq "develop-2.0.0" OR
+      pull_request.target match "release/*") AND
+      NOT pull_request.draft AND
+      (pull_request.changes.any match "com.unity.netcode.gameobjects/**" OR
+      pull_request.changes.any match "testproject/**"))
     cancel_old_ci: true
-    pull_requests:
-      - targets:
-          only:
-            - "develop"
-            - "develop-2.0.0"
-            - "/release\/.*/"
-      - drafts: false
-
 
 # Run all tests on 6000.2 (latest supported editor) on nightly basis.
 # Same subset as pull_request_trigger with addition of mobile/desktop/console tests and webgl builds