backend-common: wrap branch command

Signed-off-by: Magnus Persson <magnus.persson@fortnox.se>

.changeset/smooth-camels-melt.md

@@ -0,0 +1,5 @@
+---
+'@backstage/backend-common': patch
+---
+
+The `branch` command has been added to the `Git` isomorphic-git wrapper.

packages/backend-common/api-report.md

@@ -342,6 +342,8 @@ export class Git {
     force?: boolean;
   }): Promise<void>;
   // (undocumented)
+  branch(options: { dir: string; ref: string }): Promise<void>;
+  // (undocumented)
   checkout(options: { dir: string; ref: string }): Promise<void>;
   clone(options: {
     url: string;

packages/backend-common/src/scm/git.test.ts

@@ -95,6 +95,22 @@ describe('Git', () => {
     });
   });
 
+  describe('branch', () => {
+    it('should call isomorphic-git with the correct arguments', async () => {
+      const git = Git.fromAuth({});
+      const dir = 'mockdirectory';
+      const ref = 'master';
+
+      await git.branch({ dir, ref });
+
+      expect(isomorphic.branch).toHaveBeenCalledWith({
+        fs,
+        dir,
+        ref,
+      });
+    });
+  });
+
   describe('commit', () => {
     it('should call isomorphic-git with the correct arguments', async () => {
       const git = Git.fromAuth({});

packages/backend-common/src/scm/git.ts

@@ -94,6 +94,13 @@ export class Git {
     return git.checkout({ fs, dir, ref });
   }
 
+  async branch(options: { dir: string; ref: string }): Promise<void> {
+    const { dir, ref } = options;
+    this.config.logger?.info(`Creating branch {dir=${dir},ref=${ref}`);
+
+    return git.branch({ fs, dir, ref });
+  }
+
   async commit(options: {
     dir: string;
     message: string;