Fix checkout init for SHA-256 repositories

__test__/git-auth-helper.test.ts

@@ -318,6 +318,39 @@ describe('git-auth-helper tests', () => {
     )
   })
 
+  const configureSshCommand_doesNotPersistSshCommand =
+    'configureSshCommand does not persist SSH command'
+  it(configureSshCommand_doesNotPersistSshCommand, async () => {
+    if (!sshPath) {
+      process.stdout.write(
+        `Skipped test "${configureSshCommand_doesNotPersistSshCommand}". Executable 'ssh' not found in the PATH.\n`
+      )
+      return
+    }
+
+    // Arrange
+    await setup(configureSshCommand_doesNotPersistSshCommand)
+    const authHelper = gitAuthHelper.createAuthHelper(git, settings)
+
+    // Act
+    await authHelper.configureSshCommand()
+
+    // Assert git env var
+    expect(git.setEnvironmentVariable).toHaveBeenCalledWith(
+      'GIT_SSH_COMMAND',
+      expect.any(String)
+    )
+
+    // Assert the local SSH command was not persisted for the pre-init probe
+    expect(git.config).not.toHaveBeenCalledWith(
+      'core.sshCommand',
+      expect.any(String)
+    )
+
+    await authHelper.removeSshCommand()
+    expect(git.env['GIT_SSH_COMMAND']).toBeUndefined()
+  })
+
   const configureAuth_writesExplicitKnownHosts = 'writes explicit known hosts'
   it(configureAuth_writesExplicitKnownHosts, async () => {
     if (!sshPath) {
@@ -1103,6 +1136,7 @@ async function setup(testName: string): Promise<void> {
     ),
     tryDisableAutomaticGarbageCollection: jest.fn(),
     tryGetFetchUrl: jest.fn(),
+    tryGetObjectFormat: jest.fn(async () => ({format: '', succeeded: true})),
     tryGetConfigValues: jest.fn(
       async (
         key: string,