os,internal/godebugs: add missing IncNonDefault calls

Fixes #66215

Change-Id: Id7de15feabe08f66c048dc114c09494813c9febc
Reviewed-on: https://go-review.googlesource.com/c/go/+/570695
Reviewed-by: Cherry Mui <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>
Reviewed-by: Ian Lance Taylor <[email protected]>

Author: qmuntal

src/internal/godebugs/table.go

@@ -49,8 +49,8 @@ var All = []Info{
 	{Name: "tlsmaxrsasize", Package: "crypto/tls"},
 	{Name: "tlsrsakex", Package: "crypto/tls", Changed: 22, Old: "1"},
 	{Name: "tlsunsafeekm", Package: "crypto/tls", Changed: 22, Old: "1"},
-	{Name: "winreadlinkvolume", Package: "os", Changed: 22, Old: "0", Opaque: true}, // bug #66215: remove Opaque
-	{Name: "winsymlink", Package: "os", Changed: 22, Old: "0", Opaque: true},        // bug #66215: remove Opaque
+	{Name: "winreadlinkvolume", Package: "os", Changed: 22, Old: "0"},
+	{Name: "winsymlink", Package: "os", Changed: 22, Old: "0"},
 	{Name: "x509sha1", Package: "crypto/x509"},
 	{Name: "x509usefallbackroots", Package: "crypto/x509"},
 	{Name: "x509usepolicies", Package: "crypto/x509"},

src/os/file_windows.go

@@ -378,6 +378,7 @@ func normaliseLinkPath(path string) (string, error) {
 	if winreadlinkvolume.Value() != "0" {
 		return `\\?\` + path[4:], nil
 	}
+	winreadlinkvolume.IncNonDefault()
 
 	h, err := openSymlink(path)
 	if err != nil {

src/os/types_windows.go

@@ -161,10 +161,19 @@ func (fs *fileStat) Size() int64 {
 
 var winsymlink = godebug.New("winsymlink")
 
-func (fs *fileStat) Mode() (m FileMode) {
+func (fs *fileStat) Mode() FileMode {
+	m := fs.mode()
 	if winsymlink.Value() == "0" {
-		return fs.modePreGo1_23()
+		old := fs.modePreGo1_23()
+		if old != m {
+			winsymlink.IncNonDefault()
+			m = old
+		}
 	}
+	return m
+}
+
+func (fs *fileStat) mode() (m FileMode) {
 	if fs.FileAttributes&syscall.FILE_ATTRIBUTE_READONLY != 0 {
 		m |= 0444
 	} else {

src/runtime/metrics/doc.go

@@ -310,6 +310,14 @@ Below is the full list of supported metrics, ordered lexicographically.
 		The number of non-default behaviors executed by the crypto/tls
 		package due to a non-default GODEBUG=tlsunsafeekm=... setting.
 
+	/godebug/non-default-behavior/winreadlinkvolume:events
+		The number of non-default behaviors executed by the os package
+		due to a non-default GODEBUG=winreadlinkvolume=... setting.
+
+	/godebug/non-default-behavior/winsymlink:events
+		The number of non-default behaviors executed by the os package
+		due to a non-default GODEBUG=winsymlink=... setting.
+
 	/godebug/non-default-behavior/x509sha1:events
 		The number of non-default behaviors executed by the crypto/x509
 		package due to a non-default GODEBUG=x509sha1=... setting.