fix(giterminism): prevent consistency error if .git file is not exist

Signed-off-by: Alexandr Zaytsev <alexandr.zaytsev@flant.com>

Author: nervgh

pkg/true_git/work_tree.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"io/fs"
 	"io/ioutil"
 	"os"
 	"path/filepath"
@@ -167,7 +168,17 @@ func prepareWorkTree(ctx context.Context, repoDir, workTreeCacheDir, commit stri
 }
 
 func verifyWorkTreeConsistency(ctx context.Context, repoDir, workTreeDir string) (bool, error) {
-	resolvedGitDir, err := resolveDotGitFile(ctx, filepath.Join(workTreeDir, ".git"))
+	dotGitFilePath := filepath.Join(workTreeDir, ".git")
+
+	_, err := os.Stat(dotGitFilePath)
+	switch {
+	case errors.Is(err, fs.ErrNotExist):
+		return false, nil
+	case err != nil:
+		return false, err
+	}
+
+	resolvedGitDir, err := resolveDotGitFile(ctx, dotGitFilePath)
 	if err != nil {
 		return false, fmt.Errorf("unable to resolve dot-git file %q: %w", filepath.Join(workTreeDir, ".git"), err)
 	}

pkg/true_git/work_tree_test.go

@@ -128,17 +128,25 @@ var _ = Describe("Work tree helpers", func() {
 		It("passes correct work tree", func() {
 			ctx := context.Background()
 			valid, err := verifyWorkTreeConsistency(ctx, mainWtDir, sideWtDir)
-			Expect(err).To((Succeed()))
+			Expect(err).To(Succeed())
 			Expect(valid).To(BeTrue())
 		})
 
+		It("should return false,nil if got git file is removed in working tree dir", func(ctx SpecContext) {
+			Expect(os.RemoveAll(filepath.Join(sideWtDir, ".git"))).To(Succeed())
+
+			valid, err := verifyWorkTreeConsistency(ctx, mainWtDir, sideWtDir)
+			Expect(err).To(Succeed())
+			Expect(valid).To(BeFalse())
+		})
+
 		It("detects side work tree with incorrect back dot git link", func() {
 			ctx := context.Background()
 
 			Expect(os.WriteFile(filepath.Join(sideWtDir, ".git"), []byte(fmt.Sprintf("gitdir: %s\n", filepath.Join(mainWtDir, ".git", "worktrees", "no-such-worktree"))), os.ModePerm)).To(Succeed())
 
 			valid, err := verifyWorkTreeConsistency(ctx, mainWtDir, sideWtDir)
-			Expect(err).To((Succeed()))
+			Expect(err).To(Succeed())
 			Expect(valid).To(BeFalse())
 		})
 	})