[dev.unified] all: merge master (85d87b9) into dev.unifieddev.unified

Merge List:

+ 2022-08-04 85d87b9c75 all: update vendored golang.org/x dependencies for Go 1.20 development
+ 2022-08-04 fb1bfd4d37 all: remove pre-Go 1.17 workarounds
+ 2022-08-04 44ff9bff0c runtime: clean up panic and deadlock lock ranks
+ 2022-08-04 f42dc0de74 runtime: make the lock rank DAG make more sense
+ 2022-08-04 d29a0282e9 runtime: add mayAcquire annotation for finlock
+ 2022-08-04 c5be4ed7df runtime: add missing trace lock edges
+ 2022-08-04 2b8a9a484f runtime: generate the lock ranking from a DAG description
+ 2022-08-04 ddfd639408 runtime: delete unused lock ranks
+ 2022-08-04 426ea5702b internal/dag: add a Graph type and make node order deterministic
+ 2022-08-04 d37cc9a8cd go/build, internal/dag: lift DAG parser into an internal package
+ 2022-08-04 ab0a94c6d3 cmd/dist: require Go 1.17 for building Go
+ 2022-08-04 1e3c19f3fe runtime: support riscv64 SV57 mode
+ 2022-08-03 f28fa952b5 make.bat, make.rc: show bootstrap toolchain version
+ 2022-08-03 87384801dc cmd/asm: update package doc to describe "-p" option
+ 2022-08-03 c6a2dada0d net: disable TestIPv6WriteMsgUDPAddrPortTargetAddrIPVersion [sic] on DragonflyBSD
+ 2022-08-02 29b9a328d2 runtime: trivial replacements of g in remaining files
+ 2022-08-02 c647264619 runtime: trivial replacements of g in signal_unix.go
+ 2022-08-02 399f50c9d7 runtime: tricky replacements of g in traceback.go
+ 2022-08-02 4509e951ec runtime: tricky replacements of g in proc.go
+ 2022-08-02 4400238ec8 runtime: trivial replacements of _g_ in remaining files
+ 2022-08-02 5999a28de8 runtime: trivial replacements of _g_ in os files
+ 2022-08-02 0e18cf6d09 runtime: trivial replacements of _g_ in GC files
+ 2022-08-02 4358a53a97 runtime: trivial replacements of _g_ in proc.go
+ 2022-08-02 b486518964 runtime: tricky replacements of _g_ in os3_solaris.go
+ 2022-08-02 54a0ab3f7b runtime: tricky replacements of _g_ in os3_plan9.go
+ 2022-08-02 4240ff764b runtime: tricky replacements of _g_ in signal_windows.go
+ 2022-08-02 8666d89ca8 runtime: tricky replacements of _g_ in signal_unix.go
+ 2022-08-02 74cee276fe runtime: tricky replacements of _g_ in trace.go
+ 2022-08-02 222799fde6 runtime: tricky replacements of _g_ in mgc.go
+ 2022-08-02 e9d7f54a1a runtime: tricky replacements of _g_ in proc.go
+ 2022-08-02 5e8d261918 runtime: rename _p_ to pp
+ 2022-08-02 0ad2ec6596 runtime: clean up dopanic_m
+ 2022-08-02 7e952962df runtime: clean up canpanic
+ 2022-08-02 9dbc0f3556 runtime: fix outdated g.m comment in traceback.go
+ 2022-08-02 d723df76da internal/goversion: update Version to 1.20
+ 2022-08-02 1b7e71e8ae all: disable tests that fail on Alpine
+ 2022-08-01 f2a9f3e2e0 test: improve generic type assertion test
+ 2022-08-01 27038b70f8 cmd/compile: fix wrong dict pass condition for type assertions
+ 2022-08-01 e99f53fed9 doc: move Go 1.19 release notes to x/website
+ 2022-08-01 8b13a073a1 doc: mention removal of cmd/compile's -importmap and -installsuffix flags
+ 2022-08-01 e95fd4c238 doc/go1.19: fix typo: EM_LONGARCH -> EM_LOONGARCH
+ 2022-08-01 dee3efd9f8 doc/go1.19: fix a few links that were missing trailing slashes
+ 2022-07-30 f32519e5fb runtime: fix typos
+ 2022-07-29 9a2001a8cc cmd/dist: always pass -short=true with -quick
+ 2022-07-28 5c8ec89cb5 doc/go1.19: minor adjustments and links
+ 2022-07-28 417be37048 doc/go1.19: improve the loong64 release notes
+ 2022-07-28 027855e8d8 os/exec: add GODEBUG setting to opt out of ErrDot changes

Change-Id: Idc0fbe93978c0dff7600b90a2c3ecc067fd9f5f2

5 files changed, 66 insertions, 37 deletions

diff --git a/src/os/exec/dot_test.go b/src/os/exec/dot_test.go
index e2d2dba7a5..306f98cbaa 100644
--- a/src/os/exec/dot_test.go
+++ b/src/os/exec/dot_test.go
@@ -56,40 +56,58 @@ func TestLookPath(t *testing.T) {
 
 	// Add "." to PATH so that exec.LookPath looks in the current directory on all systems.
 	// And try to trick it with "../testdir" too.
-	for _, dir := range []string{".", "../testdir"} {
-		t.Run(pathVar+"="+dir, func(t *testing.T) {
-			t.Setenv(pathVar, dir+string(filepath.ListSeparator)+origPath)
-			good := dir + "/execabs-test"
-			if found, err := LookPath(good); err != nil || !strings.HasPrefix(found, good) {
-				t.Fatalf(`LookPath(%#q) = %#q, %v, want "%s...", nil`, good, found, err, good)
-			}
-			if runtime.GOOS == "windows" {
-				good = dir + `\execabs-test`
-				if found, err := LookPath(good); err != nil || !strings.HasPrefix(found, good) {
-					t.Fatalf(`LookPath(%#q) = %#q, %v, want "%s...", nil`, good, found, err, good)
-				}
-			}
-
-			if _, err := LookPath("execabs-test"); err == nil {
-				t.Fatalf("LookPath didn't fail when finding a non-relative path")
-			} else if !errors.Is(err, ErrDot) {
-				t.Fatalf("LookPath returned unexpected error: want Is ErrDot, got %q", err)
-			}
-
-			cmd := Command("execabs-test")
-			if cmd.Err == nil {
-				t.Fatalf("Command didn't fail when finding a non-relative path")
-			} else if !errors.Is(cmd.Err, ErrDot) {
-				t.Fatalf("Command returned unexpected error: want Is ErrDot, got %q", cmd.Err)
-			}
-			cmd.Err = nil
-
-			// Clearing cmd.Err should let the execution proceed,
-			// and it should fail because it's not a valid binary.
-			if err := cmd.Run(); err == nil {
-				t.Fatalf("Run did not fail: expected exec error")
-			} else if errors.Is(err, ErrDot) {
-				t.Fatalf("Run returned unexpected error ErrDot: want error like ENOEXEC: %q", err)
+	for _, errdot := range []string{"1", "0"} {
+		t.Run("GODEBUG=execerrdot="+errdot, func(t *testing.T) {
+			t.Setenv("GODEBUG", "execerrdot="+errdot)
+			for _, dir := range []string{".", "../testdir"} {
+				t.Run(pathVar+"="+dir, func(t *testing.T) {
+					t.Setenv(pathVar, dir+string(filepath.ListSeparator)+origPath)
+					good := dir + "/execabs-test"
+					if found, err := LookPath(good); err != nil || !strings.HasPrefix(found, good) {
+						t.Fatalf(`LookPath(%#q) = %#q, %v, want "%s...", nil`, good, found, err, good)
+					}
+					if runtime.GOOS == "windows" {
+						good = dir + `\execabs-test`
+						if found, err := LookPath(good); err != nil || !strings.HasPrefix(found, good) {
+							t.Fatalf(`LookPath(%#q) = %#q, %v, want "%s...", nil`, good, found, err, good)
+						}
+					}
+
+					_, err := LookPath("execabs-test")
+					if errdot == "1" {
+						if err == nil {
+							t.Fatalf("LookPath didn't fail when finding a non-relative path")
+						} else if !errors.Is(err, ErrDot) {
+							t.Fatalf("LookPath returned unexpected error: want Is ErrDot, got %q", err)
+						}
+					} else {
+						if err != nil {
+							t.Fatalf("LookPath failed unexpectedly: %v", err)
+						}
+					}
+
+					cmd := Command("execabs-test")
+					if errdot == "1" {
+						if cmd.Err == nil {
+							t.Fatalf("Command didn't fail when finding a non-relative path")
+						} else if !errors.Is(cmd.Err, ErrDot) {
+							t.Fatalf("Command returned unexpected error: want Is ErrDot, got %q", cmd.Err)
+						}
+						cmd.Err = nil
+					} else {
+						if cmd.Err != nil {
+							t.Fatalf("Command failed unexpectedly: %v", err)
+						}
+					}
+
+					// Clearing cmd.Err should let the execution proceed,
+					// and it should fail because it's not a valid binary.
+					if err := cmd.Run(); err == nil {
+						t.Fatalf("Run did not fail: expected exec error")
+					} else if errors.Is(err, ErrDot) {
+						t.Fatalf("Run returned unexpected error ErrDot: want error like ENOEXEC: %q", err)
+					}
+				})
 			}
 		})
 	}
diff --git a/src/os/exec/exec.go b/src/os/exec/exec.go
index 57d18420bb..737aaab6a7 100644
--- a/src/os/exec/exec.go
+++ b/src/os/exec/exec.go
@@ -80,6 +80,11 @@
 //		log.Fatal(err)
 //	}
 //
+// Setting the environment variable GODEBUG=execerrdot=0
+// disables generation of ErrDot entirely, temporarily restoring the pre-Go 1.19
+// behavior for programs that are unable to apply more targeted fixes.
+// A future version of Go may remove support for this variable.
+//
 // Before adding such overrides, make sure you understand the
 // security implications of doing so.
 // See https://go.dev/blog/path-security for more information.
diff --git a/src/os/exec/lp_plan9.go b/src/os/exec/lp_plan9.go
index 68224814d1..092684f03a 100644
--- a/src/os/exec/lp_plan9.go
+++ b/src/os/exec/lp_plan9.go
@@ -6,6 +6,7 @@ package exec
 
 import (
 	"errors"
+	"internal/godebug"
 	"io/fs"
 	"os"
 	"path/filepath"
@@ -53,7 +54,7 @@ func LookPath(file string) (string, error) {
 	for _, dir := range filepath.SplitList(path) {
 		path := filepath.Join(dir, file)
 		if err := findExecutable(path); err == nil {
-			if !filepath.IsAbs(path) {
+			if !filepath.IsAbs(path) && godebug.Get("execerrdot") != "0" {
 				return path, &Error{file, ErrDot}
 			}
 			return path, nil
diff --git a/src/os/exec/lp_unix.go b/src/os/exec/lp_unix.go
index 9833205663..b2b412c96b 100644
--- a/src/os/exec/lp_unix.go
+++ b/src/os/exec/lp_unix.go
@@ -8,6 +8,7 @@ package exec
 
 import (
 	"errors"
+	"internal/godebug"
 	"io/fs"
 	"os"
 	"path/filepath"
@@ -56,7 +57,7 @@ func LookPath(file string) (string, error) {
 		}
 		path := filepath.Join(dir, file)
 		if err := findExecutable(path); err == nil {
-			if !filepath.IsAbs(path) {
+			if !filepath.IsAbs(path) && godebug.Get("execerrdot") != "0" {
 				return path, &Error{file, ErrDot}
 			}
 			return path, nil
diff --git a/src/os/exec/lp_windows.go b/src/os/exec/lp_windows.go
index da047585eb..ec45db7459 100644
--- a/src/os/exec/lp_windows.go
+++ b/src/os/exec/lp_windows.go
@@ -6,6 +6,7 @@ package exec
 
 import (
 	"errors"
+	"internal/godebug"
 	"io/fs"
 	"os"
 	"path/filepath"
@@ -102,6 +103,9 @@ func LookPath(file string) (string, error) {
 	)
 	if _, found := syscall.Getenv("NoDefaultCurrentDirectoryInExePath"); !found {
 		if f, err := findExecutable(filepath.Join(".", file), exts); err == nil {
+			if godebug.Get("execerrdot") == "0" {
+				return f, nil
+			}
 			dotf, dotErr = f, &Error{file, ErrDot}
 		}
 	}
@@ -124,7 +128,7 @@ func LookPath(file string) (string, error) {
 				}
 			}
 
-			if !filepath.IsAbs(f) {
+			if !filepath.IsAbs(f) && godebug.Get("execerrdot") != "0" {
 				return f, &Error{file, ErrDot}
 			}
 			return f, nil