path/filepath: fix EvalSymlinks(".") on windows

Also new tests added. So, perhaps, this CL corrects
even more broken EvalSymlinks behaviour.

Fixes #12451

Change-Id: I81b9d92bab74bcb8eca6db6633546982fe5cec87
Reviewed-on: https://go-review.googlesource.com/16192
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

1 files changed, 83 insertions, 2 deletions

diff --git a/src/path/filepath/path_test.go b/src/path/filepath/path_test.go
index b0c37b0f4c..09e7be228a 100644
--- a/src/path/filepath/path_test.go
+++ b/src/path/filepath/path_test.go
@@ -752,6 +752,18 @@ var EvalSymlinksTests = []EvalSymlinksTest{
 	{"test/linkabs", "/"},
 }
 
+// findEvalSymlinksTestDirsDest searches testDirs
+// for matching path and returns correspondent dest.
+func findEvalSymlinksTestDirsDest(t *testing.T, testDirs []EvalSymlinksTest, path string) string {
+	for _, d := range testDirs {
+		if d.path == path {
+			return d.dest
+		}
+	}
+	t.Fatalf("did not find %q in testDirs slice", path)
+	return ""
+}
+
 // simpleJoin builds a file name from the directory and path.
 // It does not use Join because we don't want ".." to be evaluated.
 func simpleJoin(dir, path string) string {
@@ -780,8 +792,22 @@ func TestEvalSymlinks(t *testing.T) {
 		t.Fatal("eval symlink for tmp dir:", err)
 	}
 
+	tests := EvalSymlinksTests
+	testdirs := EvalSymlinksTestDirs
+	if runtime.GOOS == "windows" {
+		if len(tmpDir) < 3 {
+			t.Fatalf("tmpDir path %q is too short", tmpDir)
+		}
+		if tmpDir[1] != ':' {
+			t.Fatalf("tmpDir path %q must have drive letter in it", tmpDir)
+		}
+		newtest := EvalSymlinksTest{"test/linkabswin", tmpDir[:3]}
+		tests = append(tests, newtest)
+		testdirs = append(testdirs, newtest)
+	}
+
 	// Create the symlink farm using relative paths.
-	for _, d := range EvalSymlinksTestDirs {
+	for _, d := range testdirs {
 		var err error
 		path := simpleJoin(tmpDir, d.path)
 		if d.dest == "" {
@@ -794,8 +820,13 @@ func TestEvalSymlinks(t *testing.T) {
 		}
 	}
 
+	wd, err := os.Getwd()
+	if err != nil {
+		t.Fatal(err)
+	}
+
 	// Evaluate the symlink farm.
-	for _, d := range EvalSymlinksTests {
+	for _, d := range tests {
 		path := simpleJoin(tmpDir, d.path)
 		dest := simpleJoin(tmpDir, d.dest)
 		if filepath.IsAbs(d.dest) || os.IsPathSeparator(d.dest[0]) {
@@ -806,6 +837,56 @@ func TestEvalSymlinks(t *testing.T) {
 		} else if filepath.Clean(p) != filepath.Clean(dest) {
 			t.Errorf("Clean(%q)=%q, want %q", path, p, dest)
 		}
+
+		// test EvalSymlinks(".")
+		func() {
+			defer func() {
+				err := os.Chdir(wd)
+				if err != nil {
+					t.Fatal(err)
+				}
+			}()
+
+			err := os.Chdir(path)
+			if err != nil {
+				t.Error(err)
+				return
+			}
+			p, err := filepath.EvalSymlinks(".")
+			if err != nil {
+				t.Errorf(`EvalSymlinks(".") in %q directory error: %v`, d.path, err)
+				return
+			}
+			if p == "." {
+				return
+			}
+			want := filepath.Clean(findEvalSymlinksTestDirsDest(t, testdirs, d.path))
+			if p == want {
+				return
+			}
+			t.Errorf(`EvalSymlinks(".") in %q directory returns %q, want "." or %q`, d.path, p, want)
+		}()
+
+		// test EvalSymlinks where parameter is relative path
+		func() {
+			defer func() {
+				err := os.Chdir(wd)
+				if err != nil {
+					t.Fatal(err)
+				}
+			}()
+
+			err := os.Chdir(tmpDir)
+			if err != nil {
+				t.Error(err)
+				return
+			}
+			if p, err := filepath.EvalSymlinks(d.path); err != nil {
+				t.Errorf("EvalSymlinks(%q) error: %v", d.path, err)
+			} else if filepath.Clean(p) != filepath.Clean(d.dest) {
+				t.Errorf("Clean(%q)=%q, want %q", d.path, p, d.dest)
+			}
+		}()
 	}
 }