Base number of commits off of the branch on origin

src/jest.setup.js

@@ -26,4 +26,24 @@ expect.extend({
       pass,
     };
   },
+
+  toBeParsableToANumber(received) {
+    let pass = false;
+    let errorMessage = '';
+
+    try {
+      Number.parseInt(received, 10);
+      pass = true;
+    } catch (error) {
+      errorMessage = error;
+    }
+
+    const message = () => `Expected ${this.utils.printExpected(received)} to be parsable as a number
+      , but received error: ${this.utils.printReceived(errorMessage)}.`;
+
+    return {
+      message,
+      pass,
+    };
+  },
 });

src/model/system.test.js

@@ -44,5 +44,13 @@ describe('System', () => {
       expect(info).toHaveBeenCalledTimes(2);
       expect(info).toHaveBeenLastCalledWith('3\n');
     });
+
+    it('allows pipes using buffer', async () => {
+      await expect(
+        System.run('sh', undefined, {
+          input: Buffer.from('git tag --list --merged HEAD | grep v[0-9]* | wc -l'),
+        }),
+      ).resolves.toBeParsableToANumber();
+    });
   });
 });

src/model/versioning.js

@@ -183,25 +183,27 @@ export default class Versioning {
    * Whether or not the repository has any version tags yet.
    */
   static async hasAnyVersionTags() {
-    const numberOfVersionCommits = await System.run('git', [
+    const numberOfCommitsAsString = await System.run('sh', undefined, {
-      'tag',
+      input: Buffer.from('git tag --list --merged HEAD | grep v[0-9]* | wc -l'),
-      '--list',
+      silent: false,
-      '--merged',
+    });
-      'HEAD',
-      '|',
-      'grep v[0-9]*',
-      '|',
-      'wc -l',
-    ]);
 
-    return numberOfVersionCommits !== '0';
+    const numberOfCommits = Number.parseInt(numberOfCommitsAsString, 10);
+
+    return numberOfCommits !== 0;
   }
 
   /**
    * Get the total number of commits on head.
+   *
+   * Note: HEAD should not be used, as it may be detached, resulting in an additional count.
    */
   static async getTotalNumberOfCommits() {
-    const numberOfCommitsAsString = await System.run('git', ['rev-list', '--count', 'HEAD']);
+    const numberOfCommitsAsString = await System.run('git', [
+      'rev-list',
+      '--count',
+      `origin/${this.branch}`,
+    ]);
 
     return Number.parseInt(numberOfCommitsAsString, 10);
   }