Verify minimum Git version for sparse checkout

The `git sparse-checkout` command is available only since Git version
v2.25.0. The `actions/checkout` Action actually supports older Git
versions than that; As of time of writing, the minimum version is
v2.18.0.

Instead of raising this minimum version even for users who do not
require a sparse checkout, only check for this minimum version
specifically when a sparse checkout was asked for.

Suggested-by: Tingluo Huang <tingluohuang@github.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

src/git-command-manager.ts

@@ -61,9 +61,14 @@ export interface IGitCommandManager {
 
 export async function createCommandManager(
   workingDirectory: string,
-  lfs: boolean
+  lfs: boolean,
+  doSparseCheckout: boolean
 ): Promise<IGitCommandManager> {
-  return await GitCommandManager.createCommandManager(workingDirectory, lfs)
+  return await GitCommandManager.createCommandManager(
+    workingDirectory,
+    lfs,
+    doSparseCheckout
+  )
 }
 
 class GitCommandManager {
@@ -73,6 +78,7 @@ class GitCommandManager {
   }
   private gitPath = ''
   private lfs = false
+  private doSparseCheckout = false
   private workingDirectory = ''
 
   // Private constructor; use createCommandManager()
@@ -461,10 +467,15 @@ class GitCommandManager {
 
   static async createCommandManager(
     workingDirectory: string,
-    lfs: boolean
+    lfs: boolean,
+    doSparseCheckout: boolean
   ): Promise<GitCommandManager> {
     const result = new GitCommandManager()
-    await result.initializeCommandManager(workingDirectory, lfs)
+    await result.initializeCommandManager(
+      workingDirectory,
+      lfs,
+      doSparseCheckout
+    )
     return result
   }
 
@@ -514,7 +525,8 @@ class GitCommandManager {
 
   private async initializeCommandManager(
     workingDirectory: string,
-    lfs: boolean
+    lfs: boolean,
+    doSparseCheckout: boolean
   ): Promise<void> {
     this.workingDirectory = workingDirectory
 
@@ -577,6 +589,16 @@ class GitCommandManager {
       }
     }
 
+    this.doSparseCheckout = doSparseCheckout
+    if (this.doSparseCheckout) {
+      // The `git sparse-checkout` command was introduced in Git v2.25.0
+      const minimumGitSparseCheckoutVersion = new GitVersion('2.25')
+      if (!gitVersion.checkMinimum(minimumGitSparseCheckoutVersion)) {
+        throw new Error(
+          `Minimum Git version required for sparse checkout is ${minimumGitSparseCheckoutVersion}. Your git ('${this.gitPath}') is ${gitVersion}`
+        )
+      }
+    }
     // Set the user agent
     const gitHttpUserAgent = `git/${gitVersion} (github-actions-checkout)`
     core.debug(`Set git useragent to: ${gitHttpUserAgent}`)

src/git-source-provider.ts

@@ -275,7 +275,11 @@ export async function cleanup(repositoryPath: string): Promise<void> {
 
   let git: IGitCommandManager
   try {
-    git = await gitCommandManager.createCommandManager(repositoryPath, false)
+    git = await gitCommandManager.createCommandManager(
+      repositoryPath,
+      false,
+      false
+    )
   } catch {
     return
   }
@@ -311,7 +315,8 @@ async function getGitCommandManager(
   try {
     return await gitCommandManager.createCommandManager(
       settings.repositoryPath,
-      settings.lfs
+      settings.lfs,
+      settings.sparseCheckout != null
     )
   } catch (err) {
     // Git is required for LFS