cmd/link: detect -X setting non-string variable

Fixes #9621.

Change-Id: Ib9c6001378364af899f57fd4b89fb23af2042923
Reviewed-on: https://go-review.googlesource.com/11694
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>

1 files changed, 18 insertions, 0 deletions

diff --git a/test/linkx_run.go b/test/linkx_run.go
index cc0f55cf92..a6c7c67014 100644
--- a/test/linkx_run.go
+++ b/test/linkx_run.go
@@ -14,6 +14,7 @@ import (
 	"fmt"
 	"os"
 	"os/exec"
+	"strings"
 )
 
 func main() {
@@ -49,4 +50,21 @@ func test(sep string) {
 		fmt.Println("-X linker flag should not accept keys without values")
 		os.Exit(1)
 	}
+
+	// Issue 9621
+	cmd = exec.Command("go", "run", "-ldflags=-X main.b=false -X main.x=42", "linkx.go")
+	outx, err := cmd.CombinedOutput()
+	if err == nil {
+		fmt.Println("-X linker flag should not overwrite non-strings")
+		os.Exit(1)
+	}
+	outstr := string(outx)
+	if !strings.Contains(outstr, "main.b") {
+		fmt.Printf("-X linker flag did not diagnose overwrite of main.b\n")
+		os.Exit(1)
+	}
+	if !strings.Contains(outstr, "main.x") {
+		fmt.Printf("-X linker flag did not diagnose overwrite of main.x\n")
+		os.Exit(1)
+	}
 }