fix(git): better cross-platform path resolution and tests

The simple filepath.IsAbs() is not enough on Windows, where the relative
path may start with a separator and should then be taken relative to the
volume name.

So, introduce resolveGitPath() helper function that will do the right
thing on both Windows and other systems. As a bonus, it returns paths
converted to slashes for ease of use with the rest of the git segment:
- Git for Windows uses only slashes.
- Slashes do work as a path separator on Windows anyway.
- Some tests in git segment still use (and rightfully so) slashes.

Add tests for resolveGitPath() on both types of systems and fix
TestEnableInWorktree using a system-dependent testing constant as a root
path.

src/segments/git.go

@@ -196,18 +196,14 @@ func (g *Git) hasWorktree(gitdir *environment.FileInfo) bool {
 	// we need the parent folder to detect where the real .git folder is
 	ind = strings.LastIndex(g.workingFolder, "/.git/modules")
 	if ind > -1 {
-		if !filepath.IsAbs(g.workingFolder) {
-			g.rootFolder = filepath.Join(gitdir.ParentFolder, g.workingFolder)
-		} else {
-			g.rootFolder = g.workingFolder
-		}
+		g.rootFolder = resolveGitPath(gitdir.ParentFolder, g.workingFolder)
 		// this might be both a worktree and a submodule, where the path would look like
 		// this: path/.git/modules/module/path/worktrees/location. We cannot distinguish
 		// between worktree and a module path containing the word 'worktree,' however.
 		ind = strings.LastIndex(g.rootFolder, "/worktrees/")
 		if ind > -1 && g.env.HasFilesInDir(g.rootFolder, "gitdir") {
 			gitDir := filepath.Join(g.rootFolder, "gitdir")
-			realGitFolder := filepath.Clean(g.env.FileContent(gitDir))
+			realGitFolder := g.env.FileContent(gitDir)
 			g.realFolder = strings.TrimSuffix(realGitFolder, ".git\n")
 			g.rootFolder = g.rootFolder[:ind]
 			g.workingFolder = g.rootFolder

src/segments/git_test.go

@@ -57,6 +57,11 @@ func TestEnabledInWorkingDirectory(t *testing.T) {
 	assert.Equal(t, fileInfo.Path, g.workingFolder)
 }
 
+func TestResolveEmptyGitPath(t *testing.T) {
+	base := "base"
+	assert.Equal(t, base, resolveGitPath(base, ""))
+}
+
 func TestEnabledInWorktree(t *testing.T) {
 	cases := []struct {
 		Case                  string
@@ -67,63 +72,59 @@ func TestEnabledInWorktree(t *testing.T) {
 		ExpectedRealFolder    string
 		ExpectedWorkingFolder string
 		ExpectedRootFolder    string
-		WindowsPaths          bool
 	}{
 		{
 			Case:                  "worktree",
 			ExpectedEnabled:       true,
-			WorkingFolder:         "/dev/.git/worktrees/folder_worktree",
+			WorkingFolder:         TestRootPath + "dev/.git/worktrees/folder_worktree",
 			WorkingFolderAddon:    "gitdir",
-			WorkingFolderContent:  "/dev/worktree.git\n",
-			ExpectedWorkingFolder: "/dev/.git/worktrees/folder_worktree",
-			ExpectedRealFolder:    "/dev/worktree",
-			ExpectedRootFolder:    "/dev/.git",
+			WorkingFolderContent:  TestRootPath + "dev/worktree.git\n",
+			ExpectedWorkingFolder: TestRootPath + "dev/.git/worktrees/folder_worktree",
+			ExpectedRealFolder:    TestRootPath + "dev/worktree",
+			ExpectedRootFolder:    TestRootPath + "dev/.git",
 		},
 		{
 			Case:                  "submodule",
 			ExpectedEnabled:       true,
 			WorkingFolder:         "./.git/modules/submodule",
-			ExpectedWorkingFolder: "/dev/.git/modules/submodule",
-			ExpectedRealFolder:    "/dev/.git/modules/submodule",
-			ExpectedRootFolder:    "/dev/.git/modules/submodule",
-			WindowsPaths:          true,
+			ExpectedWorkingFolder: TestRootPath + "dev/.git/modules/submodule",
+			ExpectedRealFolder:    TestRootPath + "dev/.git/modules/submodule",
+			ExpectedRootFolder:    TestRootPath + "dev/.git/modules/submodule",
 		},
 		{
 			Case:                  "submodule with root working folder",
 			ExpectedEnabled:       true,
-			WorkingFolder:         "/repo/.git/modules/submodule",
-			ExpectedWorkingFolder: "/repo/.git/modules/submodule",
-			ExpectedRealFolder:    "/repo/.git/modules/submodule",
-			ExpectedRootFolder:    "/repo/.git/modules/submodule",
-			WindowsPaths:          true,
+			WorkingFolder:         TestRootPath + "repo/.git/modules/submodule",
+			ExpectedWorkingFolder: TestRootPath + "repo/.git/modules/submodule",
+			ExpectedRealFolder:    TestRootPath + "repo/.git/modules/submodule",
+			ExpectedRootFolder:    TestRootPath + "repo/.git/modules/submodule",
 		},
 		{
 			Case:                  "submodule with worktrees",
 			ExpectedEnabled:       true,
-			WorkingFolder:         "/dev/.git/modules/module/path/worktrees/location",
+			WorkingFolder:         TestRootPath + "dev/.git/modules/module/path/worktrees/location",
 			WorkingFolderAddon:    "gitdir",
-			WorkingFolderContent:  "/dev/worktree.git\n",
-			ExpectedWorkingFolder: "/dev/.git/modules/module/path",
-			ExpectedRealFolder:    "/dev/worktree",
-			ExpectedRootFolder:    "/dev/.git/modules/module/path",
-			WindowsPaths:          true,
+			WorkingFolderContent:  TestRootPath + "dev/worktree.git\n",
+			ExpectedWorkingFolder: TestRootPath + "dev/.git/modules/module/path",
+			ExpectedRealFolder:    TestRootPath + "dev/worktree",
+			ExpectedRootFolder:    TestRootPath + "dev/.git/modules/module/path",
 		},
 		{
 			Case:                  "separate git dir",
 			ExpectedEnabled:       true,
-			WorkingFolder:         "/dev/separate/.git/posh",
-			ExpectedWorkingFolder: "/dev/",
-			ExpectedRealFolder:    "/dev/",
-			ExpectedRootFolder:    "/dev/separate/.git/posh",
+			WorkingFolder:         TestRootPath + "dev/separate/.git/posh",
+			ExpectedWorkingFolder: TestRootPath + "dev/",
+			ExpectedRealFolder:    TestRootPath + "dev/",
+			ExpectedRootFolder:    TestRootPath + "dev/separate/.git/posh",
 		},
 	}
 	fileInfo := &environment.FileInfo{
-		Path:         "/dev/.git",
-		ParentFolder: "/dev",
+		Path:         TestRootPath + "dev/.git",
+		ParentFolder: TestRootPath + "dev",
 	}
 	for _, tc := range cases {
 		env := new(mock.MockedEnvironment)
-		env.On("FileContent", "/dev/.git").Return(fmt.Sprintf("gitdir: %s", tc.WorkingFolder))
+		env.On("FileContent", TestRootPath+"dev/.git").Return(fmt.Sprintf("gitdir: %s", tc.WorkingFolder))
 		env.On("FileContent", filepath.Join(tc.WorkingFolder, tc.WorkingFolderAddon)).Return(tc.WorkingFolderContent)
 		env.On("HasFilesInDir", tc.WorkingFolder, tc.WorkingFolderAddon).Return(true)
 		env.On("HasFilesInDir", tc.WorkingFolder, "HEAD").Return(true)
@@ -135,11 +136,6 @@ func TestEnabledInWorktree(t *testing.T) {
 			},
 		}
 		assert.Equal(t, tc.ExpectedEnabled, g.hasWorktree(fileInfo), tc.Case)
-		if tc.WindowsPaths {
-			tc.ExpectedRealFolder = filepath.Clean(tc.ExpectedRealFolder)
-			tc.ExpectedRootFolder = filepath.Clean(tc.ExpectedRootFolder)
-			tc.ExpectedWorkingFolder = filepath.Clean(tc.ExpectedWorkingFolder)
-		}
 		assert.Equal(t, tc.ExpectedWorkingFolder, g.workingFolder, tc.Case)
 		assert.Equal(t, tc.ExpectedRealFolder, g.realFolder, tc.Case)
 		assert.Equal(t, tc.ExpectedRootFolder, g.rootFolder, tc.Case)

src/segments/git_unix.go

@@ -0,0 +1,13 @@
+//go:build !windows
+
+package segments
+
+import "path/filepath"
+
+// resolveGitPath resolves path relative to base.
+func resolveGitPath(base, path string) string {
+	if filepath.IsAbs(path) {
+		return path
+	}
+	return filepath.Join(base, path)
+}

src/segments/git_unix_test.go

@@ -0,0 +1,36 @@
+//go:build !windows
+
+package segments
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+const TestRootPath = "/"
+
+func TestResolveGitPath(t *testing.T) {
+	cases := []struct {
+		Case     string
+		Base     string
+		Path     string
+		Expected string
+	}{
+		{
+			Case:     "relative path",
+			Base:     "dir/",
+			Path:     "sub",
+			Expected: "dir/sub",
+		},
+		{
+			Case:     "absolute path",
+			Base:     "/base",
+			Path:     "/absolute/path",
+			Expected: "/absolute/path",
+		},
+	}
+	for _, tc := range cases {
+		assert.Equal(t, tc.Expected, resolveGitPath(tc.Base, tc.Path), tc.Case)
+	}
+}

src/segments/git_windows.go

@@ -0,0 +1,22 @@
+package segments
+
+import "path/filepath"
+
+// resolveGitPath resolves path relative to base.
+func resolveGitPath(base, path string) string {
+	if len(path) == 0 {
+		return base
+	}
+	if filepath.IsAbs(path) {
+		return path
+	}
+	// Note that git on Windows uses slashes exclusively. And it's okay
+	// because Windows actually accepts both directory separators. More
+	// importantly, however, parts of the git segment depend on those
+	// slashes.
+	if path[0] == '/' {
+		// path is a disk-relative path.
+		return filepath.VolumeName(base) + path
+	}
+	return filepath.ToSlash(filepath.Join(base, path))
+}

src/segments/git_windows_test.go

@@ -0,0 +1,42 @@
+//go:build windows
+
+package segments
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+const TestRootPath = "C:/"
+
+func TestResolveGitPath(t *testing.T) {
+	cases := []struct {
+		Case     string
+		Base     string
+		Path     string
+		Expected string
+	}{
+		{
+			Case:     "relative path",
+			Base:     "dir\\",
+			Path:     "sub",
+			Expected: "dir/sub",
+		},
+		{
+			Case:     "absolute path",
+			Base:     "C:\\base",
+			Path:     "C:/absolute/path",
+			Expected: "C:/absolute/path",
+		},
+		{
+			Case:     "disk-relative path",
+			Base:     "C:\\base",
+			Path:     "/absolute/path",
+			Expected: "C:/absolute/path",
+		},
+	}
+	for _, tc := range cases {
+		assert.Equal(t, tc.Expected, resolveGitPath(tc.Base, tc.Path), tc.Case)
+	}
+}