Create interface for retrieving git version information (#850)

* Create interface for retrieving git version information

.changeset/silly-actors-peel.md

@@ -0,0 +1,5 @@
+---
+'simple-git': minor
+---
+
+Add `.version` to return git version information, including whether the git binary is installed.

examples/git-version.md

@@ -0,0 +1,32 @@
+## Check if git is installed
+
+To check if `git` (or the `customBinary` of your choosing) is accessible, use the
+`git.version()` api:
+
+```typescript
+import { simpleGit } from 'simple-git';
+
+const {installed} = await simpleGit().version();
+if (!installed) {
+  throw new Error(`Exit: "git" not available.`);
+}
+
+// ... continue using git commands here
+```
+
+## Check for a specific version of git
+
+Using the `git.version()` interface, you can query for the current `git` version
+information split by `major`, `minor` and `patch`:
+
+```typescript
+import { simpleGit } from 'simple-git';
+import { lt } from 'semver';
+
+const versionResult = await simpleGit().version();
+if (lt(String(versionResult), '2.1.0')) {
+  throw new Error(`Exit: "git" must be at least version 2.1.0.`);
+}
+
+// ... continue using git commands here compatible with 2.1.0 or higher
+```

simple-git/readme.md

@@ -387,9 +387,13 @@ For type details of the response for each of the tasks, please see the [TypeScri
 
 ## git stash
 
--  `.stash([ options ])` Stash the working directory, optional first argument can be an array of string arguments or [options](#how-to-specify-options) object to pass to the [git stash](https://git-scm.com/docs/git-stash) command.
+- `.stash([ options ])` Stash the working directory, optional first argument can be an array of string arguments or [options](#how-to-specify-options) object to pass to the [git stash](https://git-scm.com/docs/git-stash) command.
 
--  `.stashList([ options ])` Retrieves the stash list, optional first argument can be an object in the same format as used in [git log](#git-log).
+- `.stashList([ options ])` Retrieves the stash list, optional first argument can be an object in the same format as used in [git log](#git-log).
+
+## git version [examples](https://github.com/steveukx/git-js/blob/main/examples/git-version.md)
+
+- `.version()` retrieve the major, minor and patch for the currently installed `git`. Use the `.installed` property of the result to determine whether `git` is accessible on the path.
 
 ## changing the working directory [examples](https://github.com/steveukx/git-js/blob/main/examples/git-change-working-directory.md)
 

simple-git/src/lib/simple-git-api.ts

@@ -11,6 +11,7 @@ import { mergeTask } from './tasks/merge';
 import { pushTask } from './tasks/push';
 import { statusTask } from './tasks/status';
 import { configurationErrorTask, straightThroughStringTask } from './tasks/task';
+import version from './tasks/version';
 import { outputHandler, SimpleGitExecutor, SimpleGitTask, SimpleGitTaskCallback } from './types';
 import {
    asArray,
@@ -136,4 +137,4 @@ export class SimpleGitApi implements SimpleGitBase {
    }
 }
 
-Object.assign(SimpleGitApi.prototype, commit(), config(), grep(), log());
+Object.assign(SimpleGitApi.prototype, commit(), config(), grep(), log(), version());

simple-git/src/lib/tasks/config.ts

@@ -1,7 +1,7 @@
-import { ConfigGetResult, ConfigListSummary, SimpleGit } from '../../../typings';
+import type { ConfigGetResult, ConfigListSummary, SimpleGit } from '../../../typings';
 import { configGetParser, configListParser } from '../responses/ConfigList';
-import { SimpleGitApi } from '../simple-git-api';
-import { StringTask } from '../types';
+import type { SimpleGitApi } from '../simple-git-api';
+import type { StringTask } from '../types';
 import { trailingFunctionArgument } from '../utils';
 
 export enum GitConfigScope {

simple-git/src/lib/tasks/version.ts

@@ -0,0 +1,79 @@
+import type { SimpleGitApi } from '../simple-git-api';
+import type { SimpleGit } from '../../../typings';
+import { asNumber, ExitCodes } from '../utils';
+
+export interface VersionResult {
+   major: number;
+   minor: number;
+   patch: number;
+   agent: string;
+   installed: boolean;
+}
+
+const NOT_INSTALLED = 'installed=false';
+
+function versionResponse(
+   major = 0,
+   minor = 0,
+   patch = 0,
+   agent = '',
+   installed = true
+): VersionResult {
+   return Object.defineProperty(
+      {
+         major,
+         minor,
+         patch,
+         agent,
+         installed,
+      },
+      'toString',
+      {
+         value() {
+            return `${major}.${minor}.${patch}`;
+         },
+         configurable: false,
+         enumerable: false,
+      }
+   );
+}
+
+function notInstalledResponse() {
+   return versionResponse(0, 0, 0, '', false);
+}
+
+export default function (): Pick<SimpleGit, 'version'> {
+   return {
+      version(this: SimpleGitApi) {
+         return this._runTask({
+            commands: ['--version'],
+            format: 'utf-8',
+            parser(stdOut) {
+               if (stdOut === NOT_INSTALLED) {
+                  return notInstalledResponse();
+               }
+
+               const version = /version (\d+)\.(\d+)\.(\d+)(?:\s*\((.+)\))?/.exec(stdOut);
+
+               if (!version) {
+                  return versionResponse(0, 0, 0, stdOut);
+               }
+
+               return versionResponse(
+                  asNumber(version[1]),
+                  asNumber(version[2]),
+                  asNumber(version[3]),
+                  version[4] || ''
+               );
+            },
+            onError(result, error, done, fail) {
+               if (result.exitCode === ExitCodes.NOT_FOUND) {
+                  return done(Buffer.from(NOT_INSTALLED));
+               }
+
+               fail(error);
+            },
+         });
+      },
+   };
+}

simple-git/src/lib/utils/exit-codes.ts

@@ -5,5 +5,6 @@
 export enum ExitCodes {
    SUCCESS,
    ERROR,
+   NOT_FOUND = -2,
    UNCLEAN = 128,
 }

simple-git/test/integration/version.spec.ts

@@ -0,0 +1,29 @@
+import { createTestContext, newSimpleGit, SimpleGitTestContext } from '@simple-git/test-utils';
+
+describe('version', () => {
+   let context: SimpleGitTestContext;
+
+   beforeEach(async () => (context = await createTestContext()));
+
+   it('gets the current version', async () => {
+      const git = newSimpleGit(context.root);
+      expect(await git.version()).toEqual({
+         major: 2,
+         minor: expect.any(Number),
+         patch: expect.any(Number),
+         agent: expect.any(String),
+         installed: true,
+      });
+   });
+
+   it('gets the current version when the binary is not installed', async () => {
+      const git = newSimpleGit(context.root).customBinary('bad');
+      expect(await git.version()).toEqual({
+         major: 0,
+         minor: 0,
+         patch: 0,
+         agent: '',
+         installed: false,
+      });
+   });
+});

simple-git/typings/simple-git.d.ts

@@ -995,4 +995,11 @@ export interface SimpleGit extends SimpleGitBase {
     * Updates repository server info
     */
    updateServerInfo(callback?: types.SimpleGitTaskCallback<string>): Response<string>;
+
+   /**
+    * Retrieves `git` version information, including whether `git` is installed on the `PATH`
+    */
+   version(
+      callback?: types.SimpleGitTaskCallback<types.VersionResult>
+   ): Response<types.VersionResult>;
 }

simple-git/typings/types.d.ts

@@ -1,7 +1,7 @@
-export { RemoteWithoutRefs, RemoteWithRefs } from '../src/lib/responses/GetRemoteSummary';
-export { LogOptions, DefaultLogFields } from '../src/lib/tasks/log';
+export type { RemoteWithoutRefs, RemoteWithRefs } from '../src/lib/responses/GetRemoteSummary';
+export type { LogOptions, DefaultLogFields } from '../src/lib/tasks/log';
 
-export {
+export type {
    outputHandler,
    Options,
    TaskOptions,
@@ -10,10 +10,11 @@ export {
    SimpleGitTaskCallback,
 } from '../src/lib/types';
 
-export { ApplyOptions } from '../src/lib/tasks/apply-patch';
+export type { ApplyOptions } from '../src/lib/tasks/apply-patch';
 export { CheckRepoActions } from '../src/lib/tasks/check-is-repo';
 export { CleanOptions, CleanMode } from '../src/lib/tasks/clean';
-export { CloneOptions } from '../src/lib/tasks/clone';
+export type { CloneOptions } from '../src/lib/tasks/clone';
 export { GitConfigScope } from '../src/lib/tasks/config';
 export { GitGrepQuery, grepQueryBuilder } from '../src/lib/tasks/grep';
 export { ResetOptions, ResetMode } from '../src/lib/tasks/reset';
+export type { VersionResult } from '../src/lib/tasks/version';