feat: add extra goos support (#1646)

syscall.Errno is not available is some GOOS causing compile errors
Move syscall specific code to separate file behind build tags making it
future proof and adding support for all goos supported by the go runtime

error.go

@@ -23,7 +23,6 @@ import (
 	"net"
 	"os"
 	"reflect"
-	"syscall"
 	"time"
 
 	"go.elastic.co/apm/v2/model"
@@ -596,13 +595,6 @@ func init() {
 		details.SetAttr("syscall", syscallErr.Syscall)
 		details.Cause = append(details.Cause, syscallErr.Err)
 	}))
-	RegisterTypeErrorDetailer(reflect.TypeOf(syscall.Errno(0)), ErrorDetailerFunc(func(err error, details *ErrorDetails) {
-		errno := err.(syscall.Errno)
-		details.Code.String = errnoName(errno)
-		if details.Code.String == "" {
-			details.Code.Number = float64(errno)
-		}
-	}))
 }
 
 func errTemporary(err error) bool {

error_go120_test.go → error_syscall.go

@@ -15,30 +15,21 @@
 // specific language governing permissions and limitations
 // under the License.
 
-//go:build go1.20
-// +build go1.20
+//go:build unix || windows
 
-package apm_test
+package apm // import "go.elastic.co/apm/v2"
 
 import (
-	"context"
-	"errors"
-	"testing"
-
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-
-	"go.elastic.co/apm/v2"
-	"go.elastic.co/apm/v2/apmtest"
+	"reflect"
+	"syscall"
 )
 
-func TestErrorCauseUnwrapJoined(t *testing.T) {
-	err := errors.Join(errors.New("cause1"), errors.New("cause2"))
-	_, _, errors := apmtest.WithTransaction(func(ctx context.Context) {
-		apm.CaptureError(ctx, err).Send()
-	})
-	require.Len(t, errors, 1)
-	require.Len(t, errors[0].Exception.Cause, 2)
-	assert.Equal(t, "cause1", errors[0].Exception.Cause[0].Message)
-	assert.Equal(t, "cause2", errors[0].Exception.Cause[1].Message)
+func init() {
+	RegisterTypeErrorDetailer(reflect.TypeOf(syscall.Errno(0)), ErrorDetailerFunc(func(err error, details *ErrorDetails) {
+		errno := err.(syscall.Errno)
+		details.Code.String = errnoName(errno)
+		if details.Code.String == "" {
+			details.Code.Number = float64(errno)
+		}
+	}))
 }

error_test.go

@@ -19,6 +19,7 @@ package apm_test
 
 import (
 	"context"
+	goerrors "errors"
 	"fmt"
 	"net"
 	"os"
@@ -52,6 +53,17 @@ func TestErrorID(t *testing.T) {
 	assert.Equal(t, model.TraceID(errorID), errors[0].ID)
 }
 
+func TestErrorCauseUnwrapJoined(t *testing.T) {
+	err := goerrors.Join(errors.New("cause1"), errors.New("cause2"))
+	_, _, errors := apmtest.WithTransaction(func(ctx context.Context) {
+		apm.CaptureError(ctx, err).Send()
+	})
+	require.Len(t, errors, 1)
+	require.Len(t, errors[0].Exception.Cause, 2)
+	assert.Equal(t, "cause1", errors[0].Exception.Cause[0].Message)
+	assert.Equal(t, "cause2", errors[0].Exception.Cause[1].Message)
+}
+
 func TestErrorsStackTrace(t *testing.T) {
 	modelError := sendError(t, &errorsStackTracer{
 		"zing", newErrorsStackTrace(0, 2),

error_unix.go

@@ -15,8 +15,7 @@
 // specific language governing permissions and limitations
 // under the License.
 
-//go:build !windows
-// +build !windows
+//go:build unix
 
 package apm // import "go.elastic.co/apm/v2"
 

error_windows.go

@@ -15,6 +15,8 @@
 // specific language governing permissions and limitations
 // under the License.
 
+//go:build windows
+
 package apm // import "go.elastic.co/apm/v2"
 
 import (