Wait and retry if approvals are missing

_documentation/src/docs/tech-docs/10_setup.adoc

@@ -60,6 +60,14 @@ Specify the api token value used when ucascade is approving a merge-request thro
 * No default value.
 * If not set, `ucascade` will merge the merge-requests *without* approving them first. If set, `ucascade` will approve the merge-request using that value.
 
+==== Max retry attempts
+
+Specify the maximum number of retry attempts for operations that require waiting.
+
+* key: `ucascade.max-retry-attempts`
+* default value: `60`
+* Each retry waits 1 second before the next attempt, so a value of 60 means waiting up to 60 seconds.
+
 === GitLab: Webhook Setup
 
 In the corresponding repository or group configure a https://docs.gitlab.com/ee/user/project/integrations/webhooks.html[Webhook] pointing to the location where ucascade is available:

_documentation/src/docs/tech-docs/30_technical-documentation.adoc

@@ -28,9 +28,10 @@ For a given merge request `merge` event, 3 different independent actions can be
 
 * `previous_auto_mr_merged`: if the merged-request event corresponds to the merge of an auto merge-request, and some other auto-merge requests are open between the same two branches, then the oldest auto merge request is merged.
 * `created_auto_mr`: if the merged-request event corresponds to the merge of any merge request that requires an auto merge-request to be created (to cascade the change to the next branch), it is created and potentially directly merged. With the "blocking" and "replay" endpoints, the returned object contains a `created_auto_mr.ucascade_state` field indicating if the action was successful or why it was not. It can take the values of:
-    ** MERGED: MR was created and merged succesfully
+    ** MERGED: MR was created and merged successfully
     ** NOT_MERGED_CONFLICTS: MR was created but not merged due to existing conflicts between source and target branches that must be manually resolved
     ** NOT_MERGED_CONCURRENT_MRS: MR was created but not merged due to another existing open merge request between the same source and target branches
+    ** NOT_MERGED_MISSING_APPROVALS: MR was created but not merged because it did not receive the required approvals within the configured timeout period
     ** NOT_MERGED_UNKNOWN_REASON: MR was created but not merged due to an unknown/unexpected reason
 * `existing_branch_deleted`: if the merged-request event corresponds to the **merge** of an auto merge-request and the source branch is still present, it gets deleted.
 
@@ -62,6 +63,8 @@ This explains how ucascade determines if a new auto-merge request is created or
 include::{diagramsdir}/technical-workflow.puml[]
 ----
 
+Before attempting to merge, `ucascade` waits for the merge request to receive the required approvals. This is useful when approvals may arrive shortly after the MR is created (e.g., via automated approval workflows). The waiting period is controlled by the `ucascade.max-retry-attempts` configuration property (see xref:10_setup.adoc[Setup]).
+
 During the final stage of the success case -- merging the MR -- `ucascade` verifies if that MR has any pipeline configured. If it has, the flag `merge_when_pipeline_succeeds` is set to `true`, meaning that the merge is only to happen after all its pipelines have finished successfully. Otherwise, if it doesn't have any pipeline, this flag is set to `false`, preventing GitLab to return a 405 error (see https://gitlab.com/gitlab-org/gitlab/-/issues/355455[issue #355455] for more details).
 
 ==== existing_branch_deleted

src/main/java/service/GitLabService.java

@@ -60,6 +60,9 @@ public class GitLabService {
 	@ConfigProperty(name = "gitlab.api.token.approver")
 	Optional<String> apiTokenApprover;
 
+	@ConfigProperty(name = "ucascade.max-retry-attempts", defaultValue = "60")
+	int maxRetryAttempts;
+
 	@Inject
 	GitInfo gitInfo;
 
@@ -70,7 +73,6 @@ public class GitLabService {
 	private static final String UCASCADE_TAG = "[ucascade]";
 	private static final String UCASCADE_BRANCH_PATTERN_PREFIX = "^mr(\\d+)_";
 	private static final String UCASCADE_BRANCH_PATTERN = UCASCADE_BRANCH_PATTERN_PREFIX + ".+";
-	private static final int MAX_RETRY_ATTEMPTS = 60;
 
 	private GitLabApi gitlab;
 	private GitLabApi gitlabApprover;
@@ -404,7 +406,12 @@ private MergeRequestResult acceptAutoMergeRequest(String gitlabEventUUID, MergeR
 		final Long mrNumber = mr.getIid();
 		final Long project = mr.getProjectId();
 
-		if (!isMergeRequestApproved(gitlabEventUUID, mr)) {
+		int countDownWaitingApprovals = maxRetryAttempts;
+		while (!isMergeRequestApproved(gitlabEventUUID, mr) && countDownWaitingApprovals-- > 0) {
+			Log.infof("GitlabEvent: '%s' | Waiting for approvals in MR '!%d' in project '%d'. Retrying... %d", gitlabEventUUID, mrNumber, project, Math.abs(countDownWaitingApprovals - maxRetryAttempts));
+			sleepSeconds(1);
+		}
+		if (countDownWaitingApprovals < 0) {
 			mr = assignMrToCascadeResponsible(gitlabEventUUID, mr);
 			Log.warnf("GitlabEvent: '%s' | Merge request '!%d' in project '%d' cannot be accepted because it does not have the required amount of approvals", gitlabEventUUID, mrNumber, project);
 			MergeRequestResult result = new MergeRequestResult(mr);
@@ -427,21 +434,21 @@ private MergeRequestResult acceptAutoMergeRequest(String gitlabEventUUID, MergeR
 					.withMergeCommitMessage(String.format("%s Automatic merge: '%s' -> '%s'", UCASCADE_TAG, sourceBranchPretty, targetBranch))
 					.withShouldRemoveSourceBranch(mr.getForceRemoveSourceBranch());
 
-			int countDown = MAX_RETRY_ATTEMPTS;
-			while (state != MergeRequestUcascadeState.MERGED && countDown-- > 0) {
+			int countDownWaitingMerged = maxRetryAttempts;
+			while (state != MergeRequestUcascadeState.MERGED && countDownWaitingMerged-- > 0) {
 				boolean hasPipeline = hasPipeline(gitlabEventUUID, mr);
 				acceptMrParams.withMergeWhenPipelineSucceeds(hasPipeline);
 				Log.infof("GitlabEvent: '%s' | Merging MR '!%d': '%s' -> '%s' when pipeline succeeds: '%b'", gitlabEventUUID, mrNumber, sourceBranch, targetBranch, hasPipeline);
 				try {
 					mr = mrApi.acceptMergeRequest(project, mrNumber, acceptMrParams);
 					state = MergeRequestUcascadeState.MERGED;
 				} catch (GitLabApiException e) {
-					if (countDown == 0) {
+					if (countDownWaitingMerged == 0) {
 						Log.warnf(e, "GitlabEvent: '%s' | Cannot accept merge request '!%d' from '%s' into '%s' in project '%d'", gitlabEventUUID, mrNumber, sourceBranch, targetBranch, project);
 						state = MergeRequestUcascadeState.NOT_MERGED_UNKNOWN_REASON;
 						mr = assignMrToCascadeResponsible(gitlabEventUUID, mr);
 					} else {
-						Log.infof("GitlabEvent: '%s' | Merge failed for MR '!%d', status '%s'. Retrying... %d", gitlabEventUUID, mrNumber, mergeStatus, Math.abs(countDown - MAX_RETRY_ATTEMPTS));
+						Log.infof("GitlabEvent: '%s' | Merge failed for MR '!%d', status '%s'. Retrying... %d", gitlabEventUUID, mrNumber, mergeStatus, Math.abs(countDownWaitingMerged - maxRetryAttempts));
 						sleepSeconds(1);
 					}
 				}
@@ -499,7 +506,7 @@ private String addMrPrefixPattern(String branchName) {
 
 	private MergeRequest waitForMrReady(String gitlabEventUUID, MergeRequest mr) {
 		boolean approverExists = gitlabApprover != null;
-		int countDown = MAX_RETRY_ATTEMPTS;
+		int countDown = maxRetryAttempts;
 		String mrStatus = mr.getDetailedMergeStatus();
 		while (!isMrReady(mrStatus, approverExists, mr.getHasConflicts()) && countDown-- > 0) {
 			sleepSeconds(1);

src/test/java/com/unblu/ucascade/UcascadeTest.java

@@ -692,7 +692,7 @@ void testMergeWithoutApprovals() throws Exception {
 				.body(endsWith("\n}"))
 				.body("created_auto_mr.ucascade_state", equalTo(MergeRequestUcascadeState.NOT_MERGED_MISSING_APPROVALS.name()));
 
-		verifyRequests(12);
+		verifyRequests(13);
 	}
 
 	@Test

src/test/resources/application.properties

@@ -1,2 +1,3 @@
 gitlab.api.token=token_used_in_unit_tests_1234
-gitlab.api.token.approver=approver_token_used_in_unit_tests_1234
+gitlab.api.token.approver=approver_token_used_in_unit_tests_1234
+ucascade.max-retry-attempts=1