cmd/go/internal/script: remove special-case escaping logic for $WORK

Previously, the script engine implicitly escaped the path in the
$WORK environment variable to be the literal string '$WORK', which
produces somewhat better error messages in case of failure.

However, for a general-purpose script engine that implicit behavior is
surprising, and it isn't really necessary.

For #27494.

Change-Id: Ic1d5b8801bbd068157315685539e7cc2795b3aa5
Reviewed-on: https://go-review.googlesource.com/c/go/+/426854
Reviewed-by: Russ Cox <rsc@golang.org>
Auto-Submit: Bryan Mills <bcmills@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Bryan Mills <bcmills@google.com>

src/cmd/go/internal/script/cmds.go

@@ -707,9 +707,6 @@ func match(s *State, args []string, text, name string) error {
 		text = string(data)
 	}
 
-	// Matching against workdir would be misleading.
-	text = strings.ReplaceAll(text, s.workdir, "$WORK")
-
 	if n > 0 {
 		count := len(re.FindAllString(text, -1))
 		if count != n {

src/cmd/go/internal/script/state.go

@@ -132,13 +132,6 @@ func (s *State) ExpandEnv(str string, inRegexp bool) string {
 	return os.Expand(str, func(key string) string {
 		e := s.envMap[key]
 		if inRegexp {
-			// Replace workdir with $WORK, since we have done the same substitution in
-			// the text we're about to compare against.
-			//
-			// TODO(bcmills): This seems out-of-place in the script engine.
-			// See if we can remove it.
-			e = strings.ReplaceAll(e, s.workdir, "$WORK")
-
 			// Quote to literal strings: we want paths like C:\work\go1.4 to remain
 			// paths rather than regular expressions.
 			e = regexp.QuoteMeta(e)

src/cmd/go/script_test.go

@@ -115,11 +115,9 @@ func TestScript(t *testing.T) {
 				t.Fatal(err)
 			}
 
-			if *testWork {
-				work, _ := s.LookupEnv("WORK")
-				t.Logf("$WORK=%s", work)
-			}
 			t.Log(time.Now().UTC().Format(time.RFC3339))
+			work, _ := s.LookupEnv("WORK")
+			t.Logf("$WORK=%s", work)
 
 			// With -testsum, if a go.mod file is present in the test's initial
 			// working directory, run 'go mod tidy'.

src/cmd/go/testdata/script/build_n_cgo.txt

@@ -4,6 +4,7 @@
 # See issue golang.org/issue/37012.
 go build -n
 ! stderr '[/\\]\$WORK'
+stderr '[ =]\$WORK'
 
 -- go.mod --
 module m

src/cmd/go/testdata/script/build_relative_tmpdir.txt

@@ -5,14 +5,14 @@ cd $WORK
 mkdir tmp
 env GOTMPDIR=tmp
 go build -work a
-stderr 'WORK=\$WORK' # the test script itself converts the absolute directory back to $WORK
+stderr 'WORK='$WORK
 
 # Similarly if TMP/TMPDIR is relative.
 env GOTMPDIR=
 env TMP=tmp    # Windows
 env TMPDIR=tmp # Unix
 go build -work a
-stderr 'WORK=\$WORK'
+stderr 'WORK='$WORK
 
 -- a/a.go --
 package a

src/cmd/go/testdata/script/cache_unix.txt

@@ -17,17 +17,17 @@ env HOME=$WORK/home
 
 # With all three set, we should prefer GOCACHE.
 go env GOCACHE
-stdout '\$WORK/gocache$'
+stdout $WORK'/gocache$'
 
 # Without GOCACHE, we should prefer XDG_CACHE_HOME over HOME.
 env GOCACHE=
 go env GOCACHE
-stdout '\$WORK/xdg/go-build$$'
+stdout $WORK'/xdg/go-build$$'
 
 # With only HOME set, we should use $HOME/.cache.
 env XDG_CACHE_HOME=
 go env GOCACHE
-stdout '\$WORK/home/.cache/go-build$'
+stdout $WORK'/home/.cache/go-build$'
 
 # With no guidance from the environment, we must disable the cache, but that
 # should not cause commands that do not write to the cache to fail.

src/cmd/go/testdata/script/mod_empty_err.txt

@@ -4,20 +4,20 @@ env GO111MODULE=on
 cd $WORK
 
 go list -e -f {{.Error}} .
-stdout 'no Go files in \$WORK'
+stdout 'no Go files in '$WORK
 
 go list -e -f {{.Error}} ./empty
-stdout 'no Go files in \$WORK[/\\]empty'
+stdout 'no Go files in '$WORK${/}'empty'
 
 go list -e -f {{.Error}} ./exclude
-stdout 'build constraints exclude all Go files in \$WORK[/\\]exclude'
+stdout 'build constraints exclude all Go files in '$WORK${/}'exclude'
 
 go list -e -f {{.Error}} ./missing
 stdout 'stat '$WORK'[/\\]missing: directory not found'
 
 # use 'go build -n' because 'go list' reports no error.
 ! go build -n ./testonly
-stderr 'example.com/m/testonly: no non-test Go files in \$WORK[/\\]testonly'
+stderr 'example.com/m/testonly: no non-test Go files in '$WORK${/}'testonly'
 
 -- $WORK/go.mod --
 module example.com/m

src/cmd/go/testdata/script/mod_gobuild_import.txt

@@ -55,13 +55,13 @@ stdout w1.go
 env GO111MODULE=on
 exec $WORK/testfindonly$GOEXE gobuild.example.com/x/y/z/i $WORK
 ! stdout 'build constraints'
-stdout '^dir=\$WORK.+i err=<nil>$'
+stdout '^dir='$WORK'.+i err=<nil>$'
 
 # Issue 37153: Import with empty srcDir should work.
 env GO111MODULE=on
 exec $WORK/testfindonly$GOEXE gobuild.example.com/x/y/z/i ''
 ! stdout 'build constraints'
-stdout '^dir=\$WORK.+i err=<nil>$'
+stdout '^dir='$WORK'.+i err=<nil>$'
 
 -- go.mod --
 module gobuild.example.com/x/y/z

src/cmd/go/testdata/script/modfile_flag.txt

@@ -14,7 +14,7 @@ grep example.com/m go.alt.mod
 # 'go env GOMOD' should print the path to the real file.
 # 'go env' does not recognize the '-modfile' flag.
 go env GOMOD
-stdout '^\$WORK[/\\]gopath[/\\]src[/\\]go.mod$'
+stdout '^'$WORK${/}gopath${/}src${/}'go\.mod$'
 
 # 'go list -m' should print the effective go.mod file as GoMod though.
 go list -m -f '{{.GoMod}}'