src: do not emit warning when GOROOT_BOOTSTRAP is unset

Fixes #48155

Change-Id: I610a20d3af55035bb0b1047509361b204253801e
Reviewed-on: https://go-review.googlesource.com/c/go/+/347273
Trust: Cuong Manh Le <[email protected]>
Run-TryBot: Cuong Manh Le <[email protected]>
TryBot-Result: Go Bot <[email protected]>
Reviewed-by: Matthew Dempsky <[email protected]>

Author: cuonglm

src/make.bash

@@ -152,14 +152,17 @@ if [ "$1" = "-v" ]; then
 	shift
 fi
 
+goroot_bootstrap_set=${GOROOT_BOOTSTRAP+"true"}
 export GOROOT_BOOTSTRAP=${GOROOT_BOOTSTRAP:-$HOME/go1.4}
 export GOROOT="$(cd .. && pwd)"
 IFS=$'\n'; for go_exe in $(type -ap go); do
 	if [ ! -x "$GOROOT_BOOTSTRAP/bin/go" ]; then
 		goroot=$(GOROOT='' GOOS='' GOARCH='' "$go_exe" env GOROOT)
 		if [ "$goroot" != "$GOROOT" ]; then
-			printf 'WARNING: %s does not exist, found %s from env\n' "$GOROOT_BOOTSTRAP/bin/go" "$go_exe" >&2
-			printf 'WARNING: set %s as GOROOT_BOOTSTRAP\n' "$goroot" >&2
+			if [ "$goroot_bootstrap_set" = "true" ]; then
+				printf 'WARNING: %s does not exist, found %s from env\n' "$GOROOT_BOOTSTRAP/bin/go" "$go_exe" >&2
+				printf 'WARNING: set %s as GOROOT_BOOTSTRAP\n' "$goroot" >&2
+			fi
 			GOROOT_BOOTSTRAP=$goroot
 		fi
 	fi

src/make.rc

@@ -51,15 +51,20 @@ GOENV=off
 GOFLAGS=()
 GO111MODULE=()
 GOROOT = `{cd .. && pwd}
-if(! ~ $#GOROOT_BOOTSTRAP 1)
+goroot_bootstrap_set = 'true'
+if(! ~ $#GOROOT_BOOTSTRAP 1){
+	goroot_bootstrap_set = 'false'
 	GOROOT_BOOTSTRAP = $home/go1.4
+}
 for(p in $path){
 	if(! test -x $GOROOT_BOOTSTRAP/bin/go){
 		if(go_exe = `{path=$p whatis go}){
 			goroot = `{GOROOT='' $go_exe env GOROOT}
 			if(! ~ $goroot $GOROOT){
-				echo 'WARNING: '$GOROOT_BOOTSTRAP'/bin/go does not exist, found '$go_exe' from env' >[1=2]
-				echo 'WARNING: set '$goroot' as GOROOT_BOOTSTRAP' >[1=2]
+				if(~ $goroot_bootstrap_set 'true'){
+					echo 'WARNING: '$GOROOT_BOOTSTRAP'/bin/go does not exist, found '$go_exe' from env' >[1=2]
+					echo 'WARNING: set '$goroot' as GOROOT_BOOTSTRAP' >[1=2]
+				}
 				GOROOT_BOOTSTRAP = $goroot
 			}
 		}