Allow for creating fixup! commits

pkg/commands/git.go

@@ -721,14 +721,11 @@ func (c *GitCommand) GenerateGenericRebaseTodo(commits []*Commit, index int, act
 
 // AmendTo amends the given commit with whatever files are staged
 func (c *GitCommand) AmendTo(sha string) error {
-	if err := c.OSCommand.RunCommand(fmt.Sprintf("git commit --fixup=%s", sha)); err != nil {
+	if err := c.CreateFixupCommit(sha); err != nil {
 		return err
 	}
-	return c.RunSkipEditorCommand(
-		fmt.Sprintf(
-			"git rebase --interactive --autostash --autosquash %s^", sha,
-		),
-	)
+
+	return c.SquashAllAboveFixupCommits(sha)
 }
 
 // EditRebaseTodo sets the action at a given index in the git-rebase-todo file
@@ -916,3 +913,19 @@ func (c *GitCommand) DiffCommits(sha1, sha2 string) (string, error) {
 	cmd := fmt.Sprintf("git diff --color %s %s", sha1, sha2)
 	return c.OSCommand.RunCommandWithOutput(cmd)
 }
+
+// CreateFixupCommit creates a commit that fixes up a previous commit
+func (c *GitCommand) CreateFixupCommit(sha string) error {
+	cmd := fmt.Sprintf("git commit --fixup=%s", sha)
+	return c.OSCommand.RunCommand(cmd)
+}
+
+// SquashAllAboveFixupCommits squashes all fixup! commits above the given one
+func (c *GitCommand) SquashAllAboveFixupCommits(sha string) error {
+	return c.RunSkipEditorCommand(
+		fmt.Sprintf(
+			"git rebase --interactive --autostash --autosquash %s^",
+			sha,
+		),
+	)
+}

pkg/commands/git_test.go

@@ -2066,3 +2066,38 @@ func TestGitCommandResetHardHead(t *testing.T) {
 		})
 	}
 }
+
+// TestGitCommandCreateFixupCommit is a function.
+func TestGitCommandCreateFixupCommit(t *testing.T) {
+	type scenario struct {
+		testName string
+		sha      string
+		command  func(string, ...string) *exec.Cmd
+		test     func(error)
+	}
+
+	scenarios := []scenario{
+		{
+			"valid case",
+			"12345",
+			test.CreateMockCommand(t, []*test.CommandSwapper{
+				{
+					Expect:  `git commit --fixup=12345`,
+					Replace: "echo",
+				},
+			}),
+			func(err error) {
+				assert.NoError(t, err)
+			},
+		},
+	}
+
+	gitCmd := NewDummyGitCommand()
+
+	for _, s := range scenarios {
+		t.Run(s.testName, func(t *testing.T) {
+			gitCmd.OSCommand.command = s.command
+			s.test(gitCmd.CreateFixupCommit(s.sha))
+		})
+	}
+}