Add FanOut3 helper and reorganize test helpers

Author: dirk

hooks/commit_msg_test.go

@@ -8,11 +8,11 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
-	"github.com/dirk/quickhook/testutils"
+	"github.com/dirk/quickhook/internal/test"
 )
 
-func initGitForCommitMsg(t *testing.T) testutils.TempDir {
-	tempDir := testutils.NewTempDir(t, 1)
+func initGitForCommitMsg(t *testing.T) test.TempDir {
+	tempDir := test.NewTempDir(t, 1)
 	tempDir.RequireExec("git", "init", "--quiet", ".")
 	return tempDir
 }

hooks/pre_commit.go

@@ -6,9 +6,9 @@ import (
 	"path"
 	"strings"
 
-	"github.com/samber/lo"
 	lop "github.com/samber/lo/parallel"
 
+	"github.com/dirk/quickhook/internal"
 	"github.com/dirk/quickhook/repo"
 	"github.com/dirk/quickhook/tracing"
 )
@@ -26,41 +26,32 @@ type PreCommit struct {
 // argsFiles can be non-empty with the files passed in by the user when manually running this hook,
 // or it can be empty and the list of files will be retrieved from Git.
 func (hook *PreCommit) Run(argsFiles []string) error {
-	// Resolve files to be committed in parallel with shimming git.
-	filesChan := lo.Async2(func() ([]string, error) {
-		if len(argsFiles) > 0 {
-			return argsFiles, nil
-		}
-		if files, err := hook.Repo.FilesToBeCommitted(); err != nil {
-			return nil, err
-		} else {
-			return files, nil
-		}
-	})
-	shimChan := lo.Async2(shimGit)
-	mutatingChan := lo.Async2(func() ([]string, error) {
-		return hook.Repo.FindHookExecutables(PRE_COMMIT_MUTATING_HOOK)
-	})
-	parallelChan := lo.Async2(func() ([]string, error) {
-		return hook.Repo.FindHookExecutables(PRE_COMMIT_HOOK)
-	})
-
-	dirForPath, err := (<-shimChan).Unpack()
+	// The shimming is really fast, so just do it first with a defer for cleaning up the
+	// temporary directory.
+	dirForPath, err := shimGit()
 	if err != nil {
 		return err
 	}
-	// Check the shimChan first so that if we did successfully create a directory with a shim we
-	// can make sure to clean it up if anything else errored.
 	defer os.RemoveAll(dirForPath)
-	files, err := (<-filesChan).Unpack()
-	if err != nil {
-		return err
-	}
-	mutatingExecutables, err := (<-mutatingChan).Unpack()
-	if err != nil {
-		return err
-	}
-	parallelExecutables, err := (<-parallelChan).Unpack()
+
+	files, mutatingExecutables, parallelExecutables, err := internal.FanOut3(
+		func() ([]string, error) {
+			if len(argsFiles) > 0 {
+				return argsFiles, nil
+			}
+			if files, err := hook.Repo.FilesToBeCommitted(); err != nil {
+				return nil, err
+			} else {
+				return files, nil
+			}
+		},
+		func() ([]string, error) {
+			return hook.Repo.FindHookExecutables(PRE_COMMIT_MUTATING_HOOK)
+		},
+		func() ([]string, error) {
+			return hook.Repo.FindHookExecutables(PRE_COMMIT_HOOK)
+		},
+	)
 	if err != nil {
 		return err
 	}

hooks/pre_commit_test.go

@@ -9,11 +9,11 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
-	"github.com/dirk/quickhook/testutils"
+	"github.com/dirk/quickhook/internal/test"
 )
 
-func initGitForPreCommit(t *testing.T) testutils.TempDir {
-	tempDir := testutils.NewTempDir(t, 1)
+func initGitForPreCommit(t *testing.T) test.TempDir {
+	tempDir := test.NewTempDir(t, 1)
 	tempDir.RequireExec("git", "init", "--quiet", ".")
 	tempDir.RequireExec("git", "config", "--local", "user.name", "example")
 	tempDir.RequireExec("git", "config", "--local", "user.email", "[email protected]")

install_test.go

@@ -8,12 +8,12 @@ import (
 
 	"github.com/stretchr/testify/assert"
 
+	"github.com/dirk/quickhook/internal/test"
 	"github.com/dirk/quickhook/repo"
-	"github.com/dirk/quickhook/testutils"
 )
 
 func TestInstallPreCommitYes(t *testing.T) {
-	tempDir := testutils.NewTempDir(t, 0)
+	tempDir := test.NewTempDir(t, 0)
 	tempDir.RequireExec("git", "init", "--quiet", ".")
 	tempDir.MkdirAll(".quickhook", "pre-commit")
 
@@ -28,7 +28,7 @@ func TestInstallPreCommitYes(t *testing.T) {
 }
 
 func TestInstallPreCommitMutatingYes(t *testing.T) {
-	tempDir := testutils.NewTempDir(t, 0)
+	tempDir := test.NewTempDir(t, 0)
 	tempDir.RequireExec("git", "init", "--quiet", ".")
 	tempDir.MkdirAll(".quickhook", "pre-commit-mutating")
 
@@ -43,7 +43,7 @@ func TestInstallPreCommitMutatingYes(t *testing.T) {
 }
 
 func TestInstallNoQuickhookDirectory(t *testing.T) {
-	tempDir := testutils.NewTempDir(t, 0)
+	tempDir := test.NewTempDir(t, 0)
 	tempDir.RequireExec("git", "init", "--quiet", ".")
 
 	output, err := tempDir.ExecQuickhook("install", "--yes")
@@ -85,7 +85,7 @@ func TestPromptForInstall(t *testing.T) {
 	}
 	for _, tt := range ptyTests {
 		t.Run(tt.name, func(t *testing.T) {
-			tempDir := testutils.NewTempDir(t, 0)
+			tempDir := test.NewTempDir(t, 0)
 			repo := &repo.Repo{Root: tempDir.Root}
 
 			stdin := strings.NewReader(tt.stdin)

internal/fanout.go

@@ -0,0 +1,34 @@
+package internal
+
+import "github.com/samber/lo"
+
+// Run three functions which return results or errors in parallel. If any return an error then
+// return that error (starting with the first function). If none error then return their results.
+func FanOut3[A any, B any, C any](
+	a func() (A, error),
+	b func() (B, error),
+	c func() (C, error),
+) (A, B, C, error) {
+	ch1 := lo.Async2(a)
+	ch2 := lo.Async2(b)
+	ch3 := lo.Async2(c)
+
+	var zero1 A
+	var zero2 B
+	var zero3 C
+
+	r1, err := (<-ch1).Unpack()
+	if err != nil {
+		return zero1, zero2, zero3, err
+	}
+	r2, err := (<-ch2).Unpack()
+	if err != nil {
+		return zero1, zero2, zero3, err
+	}
+	r3, err := (<-ch3).Unpack()
+	if err != nil {
+		return zero1, zero2, zero3, err
+	}
+
+	return r1, r2, r3, nil
+}

testutils/tempdir.go renamed to internal/test/tempdir.go

@@ -1,4 +1,4 @@
-package testutils
+package test
 
 import (
 	"os"