7 files changed, 377 insertions, 340 deletions
diff --git a/.gitattributes b/.gitattributes
index bcea0290f4..cabbb1732c 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -1,16 +1,16 @@
 # Treat all files in the Go repo as binary, with no git magic updating
-# line endings. Windows users contributing to Go will need to use a
-# modern version of git and editors capable of LF line endings.
+# line endings. This produces predictable results in different environments.
+#
+# Windows users contributing to Go will need to use a modern version
+# of git and editors capable of LF line endings.
+#
+# Windows .bat files are known to have multiple bugs when run with LF
+# endings, and so they are checked in with CRLF endings, with a test
+# in test/winbatch.go to catch problems. (See golang.org/issue/37791.)
 #
 # We'll prevent accidental CRLF line endings from entering the repo
-# via the git-review gofmt checks.
+# via the git-codereview gofmt checks and tests.
 #
-# See golang.org/issue/9281
+# See golang.org/issue/9281.
 
 * -text
-
-# The only exception is Windows files that must absolutely be CRLF or
-# might not work. Batch files are known to have multiple bugs when run
-# with LF endings. See golang.org/issue/37791 for more information.
-
-*.bat text eol=crlf
diff --git a/src/all.bat b/src/all.bat
index 8bbd6b1b5d..ae835d992f 100644
--- a/src/all.bat
+++ b/src/all.bat
@@ -1,27 +1,27 @@
-:: Copyright 2012 The Go Authors. All rights reserved.
-:: Use of this source code is governed by a BSD-style
-:: license that can be found in the LICENSE file.
-
-@echo off
-
-setlocal
-
-if exist make.bat goto ok
-echo all.bat must be run from go\src
-:: cannot exit: would kill parent command interpreter
-goto end
-:ok
-
-set OLDPATH=%PATH%
-call make.bat --no-banner --no-local
-if %GOBUILDFAIL%==1 goto end
-call run.bat --no-rebuild --no-local
-if %GOBUILDFAIL%==1 goto end
-:: we must restore %PATH% before running "dist banner" so that the latter
-:: can get the original %PATH% and give suggestion to add %GOROOT%/bin
-:: to %PATH% if necessary.
-set PATH=%OLDPATH%
-"%GOTOOLDIR%/dist" banner
-
-:end
-if x%GOBUILDEXIT%==x1 exit %GOBUILDFAIL%
+:: Copyright 2012 The Go Authors. All rights reserved.
+:: Use of this source code is governed by a BSD-style
+:: license that can be found in the LICENSE file.
+
+@echo off
+
+setlocal
+
+if exist make.bat goto ok
+echo all.bat must be run from go\src
+:: cannot exit: would kill parent command interpreter
+goto end
+:ok
+
+set OLDPATH=%PATH%
+call make.bat --no-banner --no-local
+if %GOBUILDFAIL%==1 goto end
+call run.bat --no-rebuild --no-local
+if %GOBUILDFAIL%==1 goto end
+:: we must restore %PATH% before running "dist banner" so that the latter
+:: can get the original %PATH% and give suggestion to add %GOROOT%/bin
+:: to %PATH% if necessary.
+set PATH=%OLDPATH%
+"%GOTOOLDIR%/dist" banner
+
+:end
+if x%GOBUILDEXIT%==x1 exit %GOBUILDFAIL%
diff --git a/src/clean.bat b/src/clean.bat
index 0954dcd67f..c957353d0f 100644
--- a/src/clean.bat
+++ b/src/clean.bat
@@ -1,32 +1,32 @@
-:: Copyright 2012 The Go Authors. All rights reserved.
-:: Use of this source code is governed by a BSD-style
-:: license that can be found in the LICENSE file.
-
-@echo off
-
-setlocal
-
-set GOBUILDFAIL=0
-
-go tool dist env -w -p >env.bat
-if errorlevel 1 goto fail
-call env.bat
-del env.bat
-echo.
-
-if exist %GOTOOLDIR%\dist.exe goto distok
-echo cannot find %GOTOOLDIR%\dist; nothing to clean
-goto fail
-:distok
-
-"%GOBIN%\go" clean -i std
-"%GOBIN%\go" tool dist clean
-"%GOBIN%\go" clean -i cmd
-
-goto end
-
-:fail
-set GOBUILDFAIL=1
-
-:end
-if x%GOBUILDEXIT%==x1 exit %GOBUILDFAIL%
+:: Copyright 2012 The Go Authors. All rights reserved.
+:: Use of this source code is governed by a BSD-style
+:: license that can be found in the LICENSE file.
+
+@echo off
+
+setlocal
+
+set GOBUILDFAIL=0
+
+go tool dist env -w -p >env.bat
+if errorlevel 1 goto fail
+call env.bat
+del env.bat
+echo.
+
+if exist %GOTOOLDIR%\dist.exe goto distok
+echo cannot find %GOTOOLDIR%\dist; nothing to clean
+goto fail
+:distok
+
+"%GOBIN%\go" clean -i std
+"%GOBIN%\go" tool dist clean
+"%GOBIN%\go" clean -i cmd
+
+goto end
+
+:fail
+set GOBUILDFAIL=1
+
+:end
+if x%GOBUILDEXIT%==x1 exit %GOBUILDFAIL%
diff --git a/src/make.bat b/src/make.bat
index f7955ec88a..277a34d5d7 100644
--- a/src/make.bat
+++ b/src/make.bat
@@ -1,153 +1,152 @@
-:: Copyright 2012 The Go Authors. All rights reserved.
-:: Use of this source code is governed by a BSD-style
-:: license that can be found in the LICENSE file.
-
-:: Environment variables that control make.bat:
-::
-:: GOROOT_FINAL: The expected final Go root, baked into binaries.
-:: The default is the location of the Go tree during the build.
-::
-:: GOHOSTARCH: The architecture for host tools (compilers and
-:: binaries).  Binaries of this type must be executable on the current
-:: system, so the only common reason to set this is to set
-:: GOHOSTARCH=386 on an amd64 machine.
-::
-:: GOARCH: The target architecture for installed packages and tools.
-::
-:: GOOS: The target operating system for installed packages and tools.
-::
-:: GO_GCFLAGS: Additional go tool compile arguments to use when
-:: building the packages and commands.
-::
-:: GO_LDFLAGS: Additional go tool link arguments to use when
-:: building the commands.
-::
-:: CGO_ENABLED: Controls cgo usage during the build. Set it to 1
-:: to include all cgo related files, .c and .go file with "cgo"
-:: build directive, in the build. Set it to 0 to ignore them.
-::
-:: CC: Command line to run to compile C code for GOHOSTARCH.
-:: Default is "gcc".
-::
-:: CC_FOR_TARGET: Command line to run compile C code for GOARCH.
-:: This is used by cgo. Default is CC.
-::
-:: FC: Command line to run to compile Fortran code.
-:: This is used by cgo. Default is "gfortran".
-
-@echo off
-
-:: Keep environment variables within this script
-:: unless invoked with --no-local.
-if x%1==x--no-local goto nolocal
-if x%2==x--no-local goto nolocal
-if x%3==x--no-local goto nolocal
-if x%4==x--no-local goto nolocal
-setlocal
-:nolocal
-
-set GOENV=off
-set GOBUILDFAIL=0
-set GOFLAGS=
-set GO111MODULE=
-
-if exist make.bat goto ok
-echo Must run make.bat from Go src directory.
-goto fail
-:ok
-
-:: Clean old generated file that will cause problems in the build.
-del /F ".\pkg\runtime\runtime_defs.go" 2>NUL
-
-:: Set GOROOT for build.
-cd ..
-set GOROOT_TEMP=%CD%
-set GOROOT=
-cd src
-set vflag=
-if x%1==x-v set vflag=-v
-if x%2==x-v set vflag=-v
-if x%3==x-v set vflag=-v
-if x%4==x-v set vflag=-v
-
-if not exist ..\bin\tool mkdir ..\bin\tool
-
-:: Calculating GOROOT_BOOTSTRAP
-if not "x%GOROOT_BOOTSTRAP%"=="x" goto bootstrapset
-for /f "tokens=*" %%g in ('where go 2^>nul') do (
-	if "x%GOROOT_BOOTSTRAP%"=="x" (
-		for /f "tokens=*" %%i in ('%%g env GOROOT 2^>nul') do (
-			if /I not %%i==%GOROOT_TEMP% (
-				set GOROOT_BOOTSTRAP=%%i
-			)
-		)
-	)
-)
-if "x%GOROOT_BOOTSTRAP%"=="x" set GOROOT_BOOTSTRAP=%HOMEDRIVE%%HOMEPATH%\Go1.4
-
-:bootstrapset
-if not exist "%GOROOT_BOOTSTRAP%\bin\go.exe" goto bootstrapfail
-set GOROOT=%GOROOT_TEMP%
-set GOROOT_TEMP=
-
-echo Building Go cmd/dist using %GOROOT_BOOTSTRAP%
-if x%vflag==x-v echo cmd/dist
-setlocal
-set GOROOT=%GOROOT_BOOTSTRAP%
-set GOOS=
-set GOARCH=
-set GOBIN=
-set GO111MODULE=off
-"%GOROOT_BOOTSTRAP%\bin\go.exe" build -o cmd\dist\dist.exe .\cmd\dist
-endlocal
-if errorlevel 1 goto fail
-.\cmd\dist\dist.exe env -w -p >env.bat
-if errorlevel 1 goto fail
-call env.bat
-del env.bat
-if x%vflag==x-v echo.
-
-if x%1==x--dist-tool goto copydist
-if x%2==x--dist-tool goto copydist
-if x%3==x--dist-tool goto copydist
-if x%4==x--dist-tool goto copydist
-
-set buildall=-a
-if x%1==x--no-clean set buildall=
-if x%2==x--no-clean set buildall=
-if x%3==x--no-clean set buildall=
-if x%4==x--no-clean set buildall=
-if x%1==x--no-banner set buildall=%buildall% --no-banner
-if x%2==x--no-banner set buildall=%buildall% --no-banner
-if x%3==x--no-banner set buildall=%buildall% --no-banner
-if x%4==x--no-banner set buildall=%buildall% --no-banner
-
-:: Run dist bootstrap to complete make.bash.
-:: Bootstrap installs a proper cmd/dist, built with the new toolchain.
-:: Throw ours, built with Go 1.4, away after bootstrap.
-.\cmd\dist\dist.exe bootstrap %vflag% %buildall%
-if errorlevel 1 goto fail
-del .\cmd\dist\dist.exe
-goto end
-
-:: DO NOT ADD ANY NEW CODE HERE.
-:: The bootstrap+del above are the final step of make.bat.
-:: If something must be added, add it to cmd/dist's cmdbootstrap,
-:: to avoid needing three copies in three different shell languages
-:: (make.bash, make.bat, make.rc).
-
-:copydist
-mkdir "%GOTOOLDIR%" 2>NUL
-copy cmd\dist\dist.exe "%GOTOOLDIR%\"
-goto end
-
-:bootstrapfail
-echo ERROR: Cannot find %GOROOT_BOOTSTRAP%\bin\go.exe
-echo Set GOROOT_BOOTSTRAP to a working Go tree ^>= Go 1.4.
-
-:fail
-set GOBUILDFAIL=1
-if x%GOBUILDEXIT%==x1 exit %GOBUILDFAIL%
-
-:end
-
+:: Copyright 2012 The Go Authors. All rights reserved.
+:: Use of this source code is governed by a BSD-style
+:: license that can be found in the LICENSE file.
+
+:: Environment variables that control make.bat:
+::
+:: GOROOT_FINAL: The expected final Go root, baked into binaries.
+:: The default is the location of the Go tree during the build.
+::
+:: GOHOSTARCH: The architecture for host tools (compilers and
+:: binaries).  Binaries of this type must be executable on the current
+:: system, so the only common reason to set this is to set
+:: GOHOSTARCH=386 on an amd64 machine.
+::
+:: GOARCH: The target architecture for installed packages and tools.
+::
+:: GOOS: The target operating system for installed packages and tools.
+::
+:: GO_GCFLAGS: Additional go tool compile arguments to use when
+:: building the packages and commands.
+::
+:: GO_LDFLAGS: Additional go tool link arguments to use when
+:: building the commands.
+::
+:: CGO_ENABLED: Controls cgo usage during the build. Set it to 1
+:: to include all cgo related files, .c and .go file with "cgo"
+:: build directive, in the build. Set it to 0 to ignore them.
+::
+:: CC: Command line to run to compile C code for GOHOSTARCH.
+:: Default is "gcc".
+::
+:: CC_FOR_TARGET: Command line to run compile C code for GOARCH.
+:: This is used by cgo. Default is CC.
+::
+:: FC: Command line to run to compile Fortran code.
+:: This is used by cgo. Default is "gfortran".
+
+@echo off
+
+:: Keep environment variables within this script
+:: unless invoked with --no-local.
+if x%1==x--no-local goto nolocal
+if x%2==x--no-local goto nolocal
+if x%3==x--no-local goto nolocal
+if x%4==x--no-local goto nolocal
+setlocal
+:nolocal
+
+set GOENV=off
+set GOBUILDFAIL=0
+set GOFLAGS=
+set GO111MODULE=
+
+if exist make.bat goto ok
+echo Must run make.bat from Go src directory.
+goto fail
+:ok
+
+:: Clean old generated file that will cause problems in the build.
+del /F ".\pkg\runtime\runtime_defs.go" 2>NUL
+
+:: Set GOROOT for build.
+cd ..
+set GOROOT_TEMP=%CD%
+set GOROOT=
+cd src
+set vflag=
+if x%1==x-v set vflag=-v
+if x%2==x-v set vflag=-v
+if x%3==x-v set vflag=-v
+if x%4==x-v set vflag=-v
+
+if not exist ..\bin\tool mkdir ..\bin\tool
+
+:: Calculating GOROOT_BOOTSTRAP
+if not "x%GOROOT_BOOTSTRAP%"=="x" goto bootstrapset
+for /f "tokens=*" %%g in ('where go 2^>nul') do (
+	if "x%GOROOT_BOOTSTRAP%"=="x" (
+		for /f "tokens=*" %%i in ('%%g env GOROOT 2^>nul') do (
+			if /I not %%i==%GOROOT_TEMP% (
+				set GOROOT_BOOTSTRAP=%%i
+			)
+		)
+	)
+)
+if "x%GOROOT_BOOTSTRAP%"=="x" set GOROOT_BOOTSTRAP=%HOMEDRIVE%%HOMEPATH%\Go1.4
+
+:bootstrapset
+if not exist "%GOROOT_BOOTSTRAP%\bin\go.exe" goto bootstrapfail
+set GOROOT=%GOROOT_TEMP%
+set GOROOT_TEMP=
+
+echo Building Go cmd/dist using %GOROOT_BOOTSTRAP%
+if x%vflag==x-v echo cmd/dist
+setlocal
+set GOROOT=%GOROOT_BOOTSTRAP%
+set GOOS=
+set GOARCH=
+set GOBIN=
+set GO111MODULE=off
+"%GOROOT_BOOTSTRAP%\bin\go.exe" build -o cmd\dist\dist.exe .\cmd\dist
+endlocal
+if errorlevel 1 goto fail
+.\cmd\dist\dist.exe env -w -p >env.bat
+if errorlevel 1 goto fail
+call env.bat
+del env.bat
+if x%vflag==x-v echo.
+
+if x%1==x--dist-tool goto copydist
+if x%2==x--dist-tool goto copydist
+if x%3==x--dist-tool goto copydist
+if x%4==x--dist-tool goto copydist
+
+set buildall=-a
+if x%1==x--no-clean set buildall=
+if x%2==x--no-clean set buildall=
+if x%3==x--no-clean set buildall=
+if x%4==x--no-clean set buildall=
+if x%1==x--no-banner set buildall=%buildall% --no-banner
+if x%2==x--no-banner set buildall=%buildall% --no-banner
+if x%3==x--no-banner set buildall=%buildall% --no-banner
+if x%4==x--no-banner set buildall=%buildall% --no-banner
+
+:: Run dist bootstrap to complete make.bash.
+:: Bootstrap installs a proper cmd/dist, built with the new toolchain.
+:: Throw ours, built with Go 1.4, away after bootstrap.
+.\cmd\dist\dist.exe bootstrap %vflag% %buildall%
+if errorlevel 1 goto fail
+del .\cmd\dist\dist.exe
+goto end
+
+:: DO NOT ADD ANY NEW CODE HERE.
+:: The bootstrap+del above are the final step of make.bat.
+:: If something must be added, add it to cmd/dist's cmdbootstrap,
+:: to avoid needing three copies in three different shell languages
+:: (make.bash, make.bat, make.rc).
+
+:copydist
+mkdir "%GOTOOLDIR%" 2>NUL
+copy cmd\dist\dist.exe "%GOTOOLDIR%\"
+goto end
+
+:bootstrapfail
+echo ERROR: Cannot find %GOROOT_BOOTSTRAP%\bin\go.exe
+echo Set GOROOT_BOOTSTRAP to a working Go tree ^>= Go 1.4.
+
+:fail
+set GOBUILDFAIL=1
+if x%GOBUILDEXIT%==x1 exit %GOBUILDFAIL%
+
+:end
diff --git a/src/race.bat b/src/race.bat
index d26f3180a3..8f0355612c 100644
--- a/src/race.bat
+++ b/src/race.bat
@@ -1,51 +1,51 @@
-:: Copyright 2013 The Go Authors. All rights reserved.
-:: Use of this source code is governed by a BSD-style
-:: license that can be found in the LICENSE file.
-
-:: race.bash tests the standard library under the race detector.
-:: https://golang.org/doc/articles/race_detector.html
-
-@echo off
-
-setlocal
-
-if exist make.bat goto ok
-echo race.bat must be run from go\src
-:: cannot exit: would kill parent command interpreter
-goto end
-:ok
-
-set GOROOT=%CD%\..
-call make.bat --dist-tool >NUL
-if errorlevel 1 goto fail
-.\cmd\dist\dist.exe env -w -p >env.bat
-if errorlevel 1 goto fail
-call env.bat
-del env.bat
-
-if %GOHOSTARCH% == amd64 goto continue
-echo Race detector is only supported on windows/amd64.
-goto fail
-
-:continue
-call make.bat --no-banner --no-local
-if %GOBUILDFAIL%==1 goto end
-echo # go install -race std
-go install -race std
-if errorlevel 1 goto fail
-
-go tool dist test -race
-
-if errorlevel 1 goto fail
-goto succ
-
-:fail
-set GOBUILDFAIL=1
-echo Fail.
-goto end
-
-:succ
-echo All tests passed.
-
-:end
-if x%GOBUILDEXIT%==x1 exit %GOBUILDFAIL%
+:: Copyright 2013 The Go Authors. All rights reserved.
+:: Use of this source code is governed by a BSD-style
+:: license that can be found in the LICENSE file.
+
+:: race.bash tests the standard library under the race detector.
+:: https://golang.org/doc/articles/race_detector.html
+
+@echo off
+
+setlocal
+
+if exist make.bat goto ok
+echo race.bat must be run from go\src
+:: cannot exit: would kill parent command interpreter
+goto end
+:ok
+
+set GOROOT=%CD%\..
+call make.bat --dist-tool >NUL
+if errorlevel 1 goto fail
+.\cmd\dist\dist.exe env -w -p >env.bat
+if errorlevel 1 goto fail
+call env.bat
+del env.bat
+
+if %GOHOSTARCH% == amd64 goto continue
+echo Race detector is only supported on windows/amd64.
+goto fail
+
+:continue
+call make.bat --no-banner --no-local
+if %GOBUILDFAIL%==1 goto end
+echo # go install -race std
+go install -race std
+if errorlevel 1 goto fail
+
+go tool dist test -race
+
+if errorlevel 1 goto fail
+goto succ
+
+:fail
+set GOBUILDFAIL=1
+echo Fail.
+goto end
+
+:succ
+echo All tests passed.
+
+:end
+if x%GOBUILDEXIT%==x1 exit %GOBUILDFAIL%
diff --git a/src/run.bat b/src/run.bat
index 69c181854b..90602b68cb 100644
--- a/src/run.bat
+++ b/src/run.bat
@@ -1,59 +1,59 @@
-:: Copyright 2012 The Go Authors. All rights reserved.
-:: Use of this source code is governed by a BSD-style
-:: license that can be found in the LICENSE file.
-
-@echo off
-
-if exist ..\bin\go.exe goto ok
-echo Must run run.bat from Go src directory after installing cmd/go.
-goto fail
-:ok
-
-:: Keep environment variables within this script
-:: unless invoked with --no-local.
-if x%1==x--no-local goto nolocal
-if x%2==x--no-local goto nolocal
-setlocal
-:nolocal
-
-set GOBUILDFAIL=0
-
-:: we disallow local import for non-local packages, if %GOROOT% happens
-:: to be under %GOPATH%, then some tests below will fail
-set GOPATH=
-:: Issue 14340: ignore GOBIN during all.bat.
-set GOBIN=
-set GOFLAGS=
-set GO111MODULE=
-
-rem TODO avoid rebuild if possible
-
-if x%1==x--no-rebuild goto norebuild
-echo ##### Building packages and commands.
-..\bin\go install -a -v std cmd
-if errorlevel 1 goto fail
-echo.
-:norebuild
-
-:: we must unset GOROOT_FINAL before tests, because runtime/debug requires
-:: correct access to source code, so if we have GOROOT_FINAL in effect,
-:: at least runtime/debug test will fail.
-set GOROOT_FINAL=
-
-:: get CGO_ENABLED
-..\bin\go env > env.bat
-if errorlevel 1 goto fail
-call env.bat
-del env.bat
-echo.
-
-..\bin\go tool dist test
-if errorlevel 1 goto fail
-echo.
-
-goto end
-
-:fail
-set GOBUILDFAIL=1
-
-:end
+:: Copyright 2012 The Go Authors. All rights reserved.
+:: Use of this source code is governed by a BSD-style
+:: license that can be found in the LICENSE file.
+
+@echo off
+
+if exist ..\bin\go.exe goto ok
+echo Must run run.bat from Go src directory after installing cmd/go.
+goto fail
+:ok
+
+:: Keep environment variables within this script
+:: unless invoked with --no-local.
+if x%1==x--no-local goto nolocal
+if x%2==x--no-local goto nolocal
+setlocal
+:nolocal
+
+set GOBUILDFAIL=0
+
+:: we disallow local import for non-local packages, if %GOROOT% happens
+:: to be under %GOPATH%, then some tests below will fail
+set GOPATH=
+:: Issue 14340: ignore GOBIN during all.bat.
+set GOBIN=
+set GOFLAGS=
+set GO111MODULE=
+
+rem TODO avoid rebuild if possible
+
+if x%1==x--no-rebuild goto norebuild
+echo ##### Building packages and commands.
+..\bin\go install -a -v std cmd
+if errorlevel 1 goto fail
+echo.
+:norebuild
+
+:: we must unset GOROOT_FINAL before tests, because runtime/debug requires
+:: correct access to source code, so if we have GOROOT_FINAL in effect,
+:: at least runtime/debug test will fail.
+set GOROOT_FINAL=
+
+:: get CGO_ENABLED
+..\bin\go env > env.bat
+if errorlevel 1 goto fail
+call env.bat
+del env.bat
+echo.
+
+..\bin\go tool dist test
+if errorlevel 1 goto fail
+echo.
+
+goto end
+
+:fail
+set GOBUILDFAIL=1
+
+:end
diff --git a/test/winbatch.go b/test/winbatch.go
index 30e0e3c982..c3b48d385c 100644
--- a/test/winbatch.go
+++ b/test/winbatch.go
@@ -4,8 +4,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// Check that batch files are maintained as CRLF files (consistent behaviour
-// on all operating systems). See https://github.com/golang/go/issues/37791
+// Check that batch files are maintained as CRLF files (consistent
+// behavior on all operating systems). See golang.org/issue/37791.
 
 package main
 
@@ -13,18 +13,56 @@ import (
 	"bytes"
 	"fmt"
 	"io/ioutil"
+	"log"
 	"os"
 	"path/filepath"
 	"runtime"
+	"strings"
 )
 
 func main() {
-	batches, _ := filepath.Glob(runtime.GOROOT() + "/src/*.bat")
-	for _, bat := range batches {
-		body, _ := ioutil.ReadFile(bat)
-		if !bytes.Contains(body, []byte("\r\n")) {
-			fmt.Printf("Windows batch file %s does not contain CRLF line termination.\nTry running git checkout src/*.bat to fix this.\n", bat)
-			os.Exit(1)
+	// Ensure that the GOROOT/src/all.bat file exists and has strict CRLF line endings.
+	enforceBatchStrictCRLF(filepath.Join(runtime.GOROOT(), "src", "all.bat"))
+
+	// Walk the entire Go repository source tree (without GOROOT/pkg),
+	// skipping directories that start with "." and named "testdata",
+	// and ensure all .bat files found have exact CRLF line endings.
+	err := filepath.Walk(runtime.GOROOT(), func(path string, fi os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+		if fi.IsDir() && (strings.HasPrefix(fi.Name(), ".") || fi.Name() == "testdata") {
+			return filepath.SkipDir
+		}
+		if path == filepath.Join(runtime.GOROOT(), "pkg") {
+			// GOROOT/pkg is known to contain generated artifacts, not source code.
+			// Skip it to avoid false positives. (Also see golang.org/issue/37929.)
+			return filepath.SkipDir
+		}
+		if filepath.Ext(fi.Name()) == ".bat" {
+			enforceBatchStrictCRLF(path)
+		}
+		return nil
+	})
+	if err != nil {
+		log.Fatalln(err)
+	}
+}
+
+func enforceBatchStrictCRLF(path string) {
+	b, err := ioutil.ReadFile(path)
+	if err != nil {
+		log.Fatalln(err)
+	}
+	cr, lf := bytes.Count(b, []byte{13}), bytes.Count(b, []byte{10})
+	crlf := bytes.Count(b, []byte{13, 10})
+	if cr != crlf || lf != crlf {
+		if rel, err := filepath.Rel(runtime.GOROOT(), path); err == nil {
+			// Make the test failure more readable by showing a path relative to GOROOT.
+			path = rel
 		}
+		fmt.Printf("Windows batch file %s does not use strict CRLF line termination.\n", path)
+		fmt.Printf("Please convert it to CRLF before checking it in due to golang.org/issue/37791.\n")
+		os.Exit(1)
 	}
 }