fix(azure): use target branch to select platform automerge strategy

lib/modules/platform/azure/__snapshots__/index.spec.ts.snap

@@ -30,7 +30,7 @@ exports[`modules/platform/azure/index createPr() should create and return a PR o
 }
 `;
 
-exports[`modules/platform/azure/index createPr() should create and return a PR object with auto-complete set 1`] = `
+exports[`modules/platform/azure/index createPr() when usePlatformAutomerge is set should create and return a PR object with auto-complete set 1`] = `
 {
   "autoCompleteSetBy": {
     "id": 123,

lib/modules/platform/azure/index.spec.ts

@@ -730,47 +730,129 @@ describe('modules/platform/azure/index', () => {
       expect(pr).toMatchSnapshot();
     });
 
-    it('should create and return a PR object with auto-complete set', async () => {
-      await initRepo({ repository: 'some/repo' });
-      const prResult = {
-        pullRequestId: 456,
-        title: 'The Title',
-        createdBy: {
-          id: 123,
-        },
-      };
-      const prUpdateResult = {
-        ...prResult,
-        autoCompleteSetBy: {
-          id: prResult.createdBy.id,
-        },
-        completionOptions: {
-          squashMerge: true,
-          deleteSourceBranch: true,
-          mergeCommitMessage: 'The Title',
-        },
-      };
-      const updateFn = jest
-        .fn(() => prUpdateResult)
-        .mockName('updatePullRequest');
-      azureApi.gitApi.mockImplementationOnce(
-        () =>
-          ({
-            createPullRequest: jest.fn(() => prResult),
-            createPullRequestLabel: jest.fn(() => ({})),
-            updatePullRequest: updateFn,
-          } as any)
-      );
-      const pr = await azure.createPr({
-        sourceBranch: 'some-branch',
-        targetBranch: 'dev',
-        prTitle: 'The Title',
-        prBody: 'Hello world',
-        labels: ['deps', 'renovate'],
-        platformOptions: { usePlatformAutomerge: true },
+    describe('when usePlatformAutomerge is set', () => {
+      it('should create and return a PR object with auto-complete set', async () => {
+        await initRepo({ repository: 'some/repo' });
+        const prResult = {
+          pullRequestId: 456,
+          title: 'The Title',
+          createdBy: {
+            id: 123,
+          },
+        };
+        const prUpdateResult = {
+          ...prResult,
+          autoCompleteSetBy: {
+            id: prResult.createdBy.id,
+          },
+          completionOptions: {
+            squashMerge: true,
+            deleteSourceBranch: true,
+            mergeCommitMessage: 'The Title',
+          },
+        };
+        const updateFn = jest
+          .fn(() => prUpdateResult)
+          .mockName('updatePullRequest');
+        azureApi.gitApi.mockImplementationOnce(
+          () =>
+            ({
+              createPullRequest: jest.fn(() => prResult),
+              createPullRequestLabel: jest.fn(() => ({})),
+              updatePullRequest: updateFn,
+            } as any)
+        );
+        const pr = await azure.createPr({
+          sourceBranch: 'some-branch',
+          targetBranch: 'dev',
+          prTitle: 'The Title',
+          prBody: 'Hello world',
+          labels: ['deps', 'renovate'],
+          platformOptions: { usePlatformAutomerge: true },
+        });
+        expect(updateFn).toHaveBeenCalled();
+        expect(pr).toMatchSnapshot();
+      });
+
+      it('should only call getMergeMethod once per run', async () => {
+        await initRepo({ repository: 'some/repo' });
+        const prResult = [
+          {
+            pullRequestId: 456,
+            title: 'The Title',
+            createdBy: {
+              id: 123,
+            },
+          },
+          {
+            pullRequestId: 457,
+            title: 'The Second Title',
+            createdBy: {
+              id: 123,
+            },
+          },
+        ];
+        const prUpdateResults = [
+          {
+            ...prResult[0],
+            autoCompleteSetBy: {
+              id: prResult[0].createdBy.id,
+            },
+            completionOptions: {
+              squashMerge: true,
+              deleteSourceBranch: true,
+              mergeCommitMessage: 'The Title',
+            },
+          },
+          {
+            ...prResult[1],
+            autoCompleteSetBy: {
+              id: prResult[1].createdBy.id,
+            },
+            completionOptions: {
+              squashMerge: true,
+              deleteSourceBranch: true,
+              mergeCommitMessage: 'The Second Title',
+            },
+          },
+        ];
+        const updateFn = jest
+          .fn(() => prUpdateResults.shift())
+          .mockName('updatePullRequest');
+
+        azureHelper.getMergeMethod.mockReturnValue(
+          Promise.resolve(GitPullRequestMergeStrategy.Squash)
+        );
+
+        azureApi.gitApi.mockImplementation(
+          () =>
+            ({
+              createPullRequest: jest.fn(() => prResult.shift()),
+              createPullRequestLabel: jest.fn(() => ({})),
+              updatePullRequest: updateFn,
+            } as any)
+        );
+        await azure.createPr({
+          sourceBranch: 'some-branch',
+          targetBranch: 'dev',
+          prTitle: 'The Title',
+          prBody: 'Hello world',
+          labels: ['deps', 'renovate'],
+          platformOptions: { usePlatformAutomerge: true },
+        });
+
+        await azure.createPr({
+          sourceBranch: 'some-other-branch',
+          targetBranch: 'dev',
+          prTitle: 'The Second Title',
+          prBody: 'Hello world',
+          labels: ['deps', 'renovate'],
+          platformOptions: { usePlatformAutomerge: true },
+        });
+
+        expect(updateFn).toHaveBeenCalledTimes(2);
+        expect(azureHelper.getMergeMethod).toHaveBeenCalledTimes(1);
       });
-      expect(updateFn).toHaveBeenCalled();
-      expect(pr).toMatchSnapshot();
     });
 
     it('should create and return an approved PR object', async () => {

lib/modules/platform/azure/index.ts

@@ -48,7 +48,6 @@ import {
   getBranchNameWithoutRefsheadsPrefix,
   getGitStatusContextCombinedName,
   getGitStatusContextFromCombinedName,
-  getProjectAndRepo,
   getRenovatePRFormat,
   getRepoByName,
   getStorageExtraCloneOpts,
@@ -57,7 +56,6 @@ import {
 
 interface Config {
   repoForceRebase: boolean;
-  defaultMergeMethod: GitPullRequestMergeStrategy;
   mergeMethods: Record<string, GitPullRequestMergeStrategy>;
   owner: string;
   repoId: string;
@@ -202,14 +200,6 @@ export async function initRepo({
   const defaultBranch = repo.defaultBranch.replace('refs/heads/', '');
   config.defaultBranch = defaultBranch;
   logger.debug(`${repository} default branch = ${defaultBranch}`);
-  const names = getProjectAndRepo(repository);
-  config.defaultMergeMethod = await azureHelper.getMergeMethod(
-    // TODO #7154
-    repo.id!,
-    names.project,
-    null,
-    defaultBranch
-  );
   config.mergeMethods = {};
   config.repoForceRebase = false;
 
@@ -427,6 +417,20 @@ export async function getBranchStatus(
   return 'green';
 }
 
+async function getMergeStrategy(
+  targetRefName: string
+): Promise<GitPullRequestMergeStrategy> {
+  return (
+    config.mergeMethods[targetRefName] ??
+    (config.mergeMethods[targetRefName] = await azureHelper.getMergeMethod(
+      config.repoId,
+      config.project,
+      targetRefName,
+      config.defaultBranch
+    ))
+  );
+}
+
 export async function createPr({
   sourceBranch,
   targetBranch,
@@ -457,14 +461,15 @@ export async function createPr({
     config.repoId
   );
   if (platformOptions?.usePlatformAutomerge) {
+    const mergeStrategy = await getMergeStrategy(pr.targetRefName!);
     pr = await azureApiGit.updatePullRequest(
       {
         autoCompleteSetBy: {
           // TODO #7154
           id: pr.createdBy!.id,
         },
         completionOptions: {
-          mergeStrategy: config.defaultMergeMethod,
+          mergeStrategy,
           deleteSourceBranch: true,
           mergeCommitMessage: title,
         },
@@ -700,21 +705,12 @@ export async function mergePr({
 
   let pr = await azureApiGit.getPullRequestById(pullRequestId, config.project);
 
-  // TODO #7154
-  const mergeMethod =
-    config.mergeMethods[pr.targetRefName!] ??
-    (config.mergeMethods[pr.targetRefName!] = await azureHelper.getMergeMethod(
-      config.repoId,
-      config.project,
-      pr.targetRefName,
-      config.defaultBranch
-    ));
-
+  const mergeStrategy = await getMergeStrategy(pr.targetRefName!);
   const objToUpdate: GitPullRequest = {
     status: PullRequestStatus.Completed,
     lastMergeSourceCommit: pr.lastMergeSourceCommit,
     completionOptions: {
-      mergeStrategy: mergeMethod,
+      mergeStrategy,
       deleteSourceBranch: true,
       mergeCommitMessage: pr.title,
     },
@@ -727,8 +723,8 @@ export async function mergePr({
       // TODO: types (#7154)
       // eslint-disable-next-line @typescript-eslint/restrict-template-expressions
       pr.lastMergeSourceCommit?.commitId
-    } using mergeStrategy ${mergeMethod} (${
-      GitPullRequestMergeStrategy[mergeMethod]
+    } using mergeStrategy ${mergeStrategy} (${
+      GitPullRequestMergeStrategy[mergeStrategy]
     })`
   );