feat: check for DDCI legacy mode before running merge base (#10624)

feat: check for DDCI legacy mode before running merge base

Merge branch 'master' into daniel.mohedano/ddci-legacy

Co-authored-by: devflow.devflow-routing-intake <devflow.devflow-routing-intake@kubernetes.us1.ddbuild.io>

Author: daniel-mohedano

dd-java-agent/agent-ci-visibility/src/main/java/datadog/trace/civisibility/CiVisibilityRepoServices.java

@@ -159,10 +159,15 @@ private static PullRequestInfo buildUserPullRequestInfo(
     String targetSha = environment.get(Constants.DDCI_PULL_REQUEST_TARGET_SHA);
     String sourceSha = environment.get(Constants.DDCI_PULL_REQUEST_SOURCE_SHA);
     String mergeBase = null;
-    try {
-      mergeBase = gitClient.getMergeBase(targetSha, sourceSha);
-    } catch (Exception ignored) {
+
+    if (!Constants.DDCI_LEGACY_KIND.equals(environment.get(Constants.DDCI_REQUEST_KIND))) {
+      // legacy mode doesn't set a valid target sha to compute the merge base
+      try {
+        mergeBase = gitClient.getMergeBase(targetSha, sourceSha);
+      } catch (Exception ignored) {
+      }
     }
+
     PullRequestInfo ddCiInfo =
         new PullRequestInfo(
             null,

dd-java-agent/agent-ci-visibility/src/main/java/datadog/trace/civisibility/Constants.java

@@ -22,4 +22,14 @@ public interface Constants {
    * the necessary data is not exposed by the CI provider
    */
   String DDCI_PULL_REQUEST_TARGET_SHA = "DDCI_PULL_REQUEST_TARGET_SHA";
+
+  /**
+   * Env var containing the DDCI mode used. When the legacy mode is used,
+   * DDCI_PULL_REQUEST_TARGET_SHA won't contain the expected value, but the previous base on the
+   * push event.
+   */
+  String DDCI_REQUEST_KIND = "DDCI_REQUEST_KIND";
+
+  // Legacy mode identifier
+  String DDCI_LEGACY_KIND = "REQUEST_KIND_LEGACY_REQUEST";
 }