feat: display only enabled merge methods (#23)

Ask github about enabled merge methods

ISSUES CLOSED: #21

src/extension.ts

@@ -131,28 +131,36 @@ class Extension {
     });
   }
 
-  private async getMergeMethdod(): Promise<MergeMethod> {
-    if (vscode.workspace.getConfiguration('github').has('preferedMergeMethod')) {
-      return vscode.workspace.getConfiguration('github').get<MergeMethod>('preferedMergeMethod');
+  private async getMergeMethdod(): Promise<MergeMethod|undefined> {
+    const preferedMethod = vscode.workspace.getConfiguration('github').get<MergeMethod>('preferedMergeMethod');
+    if (preferedMethod) {
+      return preferedMethod;
     }
-    const items: MergeOptionItems[] = [
-      {
+    const items: MergeOptionItems[] = [];
+    const enabledMethods = await this.githubManager.getEnabledMergeMethods();
+    if (enabledMethods.has('merge')) {
+      items.push({
         label: 'Create merge commit',
         description: '',
         method: 'merge'
-      },
-      {
+      });
+    }
+    if (enabledMethods.has('squash')) {
+      items.push({
         label: 'Squash and merge',
         description: '',
         method: 'squash'
-      },
-      {
+      });
+    }
+    if (enabledMethods.has('rebase')) {
+      items.push({
         label: 'Rebase and merge',
         description: '',
         method: 'rebase'
-      }
-    ];
-    return (await vscode.window.showQuickPick(items)).method;
+      });
+    }
+    const selected = await vscode.window.showQuickPick(items);
+    return selected ? selected.method : undefined;
   }
 
   private async mergePullRequest(): Promise<void> {

src/github-manager.ts

@@ -29,6 +29,22 @@ export class GitHubManager {
     return (await this.github.getRepository(owner, repository)).body.default_branch;
   }
 
+  public async getEnabledMergeMethods(): Promise<Set<MergeMethod>> {
+    const [owner, repository] = await git.getGitHubOwnerAndRepository(this.cwd);
+    const repo = await this.github.getRepository(owner, repository);
+    const set = new Set();
+    if (repo.body.allow_merge_commit) {
+      set.add('merge');
+    }
+    if (repo.body.allow_squash_merge) {
+      set.add('squash');
+    }
+    if (repo.body.allow_rebase_merge) {
+      set.add('rebase');
+    }
+    return set;
+  }
+
   public async getPullRequestForCurrentBranch(): Promise<PullRequest|undefined> {
     const [owner, repository] = await git.getGitHubOwnerAndRepository(this.cwd);
     const branch = await git.getCurrentBranch(this.cwd);

src/github.ts

@@ -27,6 +27,9 @@ export interface GitHubResponse<T> {
 
 export interface Repository {
   default_branch: string;
+  allow_rebase_merge: boolean;
+  allow_squash_merge: boolean;
+  allow_merge_commit: boolean;
 }
 
 export type MergeMethod = 'merge' | 'squash' | 'rebase';
@@ -166,6 +169,7 @@ namespace impl {
 
   export class GitHubBlueprint implements GitHub {
 
+    @Headers('Accept: application/vnd.github.polaris-preview')
     @Get('/repos/:owner/:repo')
     public getRepository(_owner: string, _repo: string): any {/* */}