build, compiler/natives/src/os: Remove syscalling os.Executable implementation.

dmitshur · dmitshur · commit 65da89e86357 · 2017-02-16T14:11:05.000-05:00
Replace it with a not-implemented-erroring one. This fixes the issue #583 where on darwin a call to os.Getwd is made, which makes syscalls, and causes a warning to be printed to console: warning: system calls not available, see https://github.com/gopherjs/gopherjs/blob/master/doc/syscalls.md os.Executable is documented to be unsupported on nacl: // Executable is not supported on nacl or OpenBSD (unless procfs is // mounted.) GOARCH=js is similar to nacl in many ways, so it's pretty expected os.Executable wouldn't be supported here either. Use https://github.com/golang/go/blob/990124da2a6ca5a54b38733b51018e2f8758cfae/src/os/executable_procfs.go#L21 as template for error message. Fixes #583.
diff --git a/build/build.go b/build/build.go
@@ -79,6 +79,8 @@ func importWithSrcDir(path string, srcDir string, mode build.ImportMode, install
 	}
 
 	switch path {
+	case "os":
+		pkg.GoFiles = stripExecutable(pkg.GoFiles) // Need to strip executable implementation files, because some of them contain package scope variables that perform (indirectly) syscalls on init.
 	case "runtime":
 		pkg.GoFiles = []string{"error.go"}
 	case "runtime/internal/sys":
@@ -116,6 +118,19 @@ func importWithSrcDir(path string, srcDir string, mode build.ImportMode, install
 	return &PackageData{Package: pkg, JSFiles: jsFiles}, nil
 }
 
+// stripExecutable strips all executable implementation .go files.
+// They have "executable_" prefix.
+func stripExecutable(goFiles []string) []string {
+	var s []string
+	for _, f := range goFiles {
+		if strings.HasPrefix(f, "executable_") {
+			continue
+		}
+		s = append(s, f)
+	}
+	return s
+}
+
 // ImportDir is like Import but processes the Go package found in the named
 // directory.
 func ImportDir(dir string, mode build.ImportMode, installSuffix string, buildTags []string) (*PackageData, error) {
diff --git a/compiler/natives/src/os/os.go b/compiler/natives/src/os/os.go
@@ -3,6 +3,8 @@
 package os
 
 import (
+	"errors"
+
 	"github.com/gopherjs/gopherjs/js"
 )
 
@@ -24,3 +26,7 @@ func init() {
 }
 
 func runtime_beforeExit() {}
+
+func executable() (string, error) {
+	return "", errors.New("Executable not implemented for GOARCH=js")
+}

Original file line number	Diff line number	Diff line change
`@@ -3,6 +3,8 @@`
`3`	`3`	`package os`
`4`	`4`
`5`	`5`	`import (`
	`6`	`+ "errors"`
	`7`	`+`
`6`	`8`	`"github.com/gopherjs/gopherjs/js"`
`7`	`9`	`)`
`8`	`10`
`@@ -24,3 +26,7 @@ func init() {`
`24`	`26`	`}`
`25`	`27`
`26`	`28`	`func runtime_beforeExit() {}`
	`29`	`+`
	`30`	`+func executable() (string, error) {`
	`31`	`+ return "", errors.New("Executable not implemented for GOARCH=js")`
	`32`	`+}`