ExitIf panics instead of exiting; Return catches

- allow Return to take either &err or &rc
- Makefile: `go vet` examples
- rename package statement to goadapt
- unexport adaptErr

Makefile

@@ -3,11 +3,16 @@ coverpkgs = $(shell echo $(packages) | tr ' ' ',')
 pkg = $(shell basename `go list`)
 cov = /tmp/$(pkg)-coverage
 
-test: 
+test: main eg
+
+main:
 	go vet
 	go test -coverprofile=$(cov).out -coverpkg=$(coverpkgs)
 	go tool cover -html=$(cov).out -o $(cov).html
 
+eg:
+	for f in examples/*.go; do go vet $$f || exit 1; done 
+
 testloop:
 	while true; do inotifywait -e MOVE *; sleep 1; make test; done
 

examples/exitif.go

@@ -13,12 +13,19 @@ import (
 var FooError = errors.New("foo error")
 
 func main() {
+	rc := run()
+	os.Exit(rc)
+}
+
+func run() (rc int) {
+	defer Return(&rc)
 	rand.Seed(time.Now().UnixNano())
 	err := mid()
 	ExitIf(err, FooError)
 	ExitIf(err, syscall.EPIPE, "pipeline %d error", 7)
 	ExitIf(err, syscall.ENOENT)
 	Ck(err)
+	return
 }
 
 func adapted() (err error) {
@@ -37,14 +44,16 @@ func mid() (err error) {
 
 func SomeFunc() (err error) {
 	defer Return(&err)
-	switch rand.Intn(3) {
+	switch rand.Intn(4) {
 	case 0:
 		return syscall.EPIPE
 	case 1:
 		return FooError
 	case 2:
 		_, err = os.Stat("/notafileordir")
 		Ck(err)
+	case 3:
+		Assert(false, "lksadjfslkjf dsalkjf")
 	}
 	return
 }

go.mod

@@ -1,3 +1,5 @@
 module github.com/stevegt/goadapt
 
 go 1.13
+
+require github.com/sirupsen/logrus v1.8.1 // indirect

go.sum

@@ -0,0 +1,7 @@
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/sirupsen/logrus v1.8.1 h1:dJKuHgqk1NNQlqoA6BTlM1Wf9DOH3NBjQyu0h9+AZZE=
+github.com/sirupsen/logrus v1.8.1/go.mod h1:yWOB1SBYBC5VeMP7gHvWumXLIWorT60ONWic61uBYv0=
+github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
+golang.org/x/sys v0.0.0-20191026070338-33540a1f6037 h1:YyJpGZS1sBuBCzLAR1VEpK193GlqGZbnPFnPV/5Rsb4=
+golang.org/x/sys v0.0.0-20191026070338-33540a1f6037/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=

main.go

@@ -1,23 +1,23 @@
-package adapt
+package goadapt
 
 import (
 	"errors"
 	"fmt"
 	"log"
-	"os"
 	"runtime"
 	"strings"
 	"syscall"
 )
 
-type AdaptErr struct {
+type adaptErr struct {
 	File string
 	Line int
 	Msg  string
 	Err  error
+	Rc   int
 }
 
-func (e AdaptErr) Error() string {
+func (e adaptErr) Error() string {
 	var s []string
 	if len(e.File) > 0 {
 		s = append(s, fmt.Sprintf("%s:%d", e.File, e.Line))
@@ -31,15 +31,15 @@ func (e AdaptErr) Error() string {
 	return strings.Join(s, ": ")
 }
 
-func (e AdaptErr) Unwrap() error {
+func (e adaptErr) Unwrap() error {
 	return e.Err
 }
 
 func Ck(err error, args ...interface{}) {
 	if err != nil {
 		_, file, line, _ := runtime.Caller(1)
 		msg := formatArgs(args...)
-		e := AdaptErr{file, line, msg, err}
+		e := adaptErr{file, line, msg, err, 0}
 		panic(&e)
 	}
 }
@@ -65,38 +65,50 @@ func Assert(cond bool, args ...interface{}) {
 		if len(args) > 1 {
 			msg += ": " + fmt.Sprintf(args[0].(string), args[1:]...)
 		}
-		e := AdaptErr{file, line, msg, nil}
+		e := adaptErr{file, line, msg, nil, 0}
 		panic(&e)
 	}
 }
 
 // convert panic into returned err
 // see https://github.com/lainio/err2 and https://blog.golang.org/go1.13-errors
-func Return(err *error, args ...interface{}) {
+func Return(out interface{}, args ...interface{}) {
 	r := recover()
 	if r == nil {
 		return
 	}
-	// r is interface{}
+	// r is an interface{}
 
-	e, ok := r.(*AdaptErr)
+	e, ok := r.(*adaptErr)
 	if !ok {
 		// wasn't us -- let the panic continue
 		panic(r)
 	}
-	// e is *AdaptErr
-	// e.Err is the original error thrown by lower call
+	// e is an *adaptErr
+	// e.Err is the error thrown by lower call
 
 	msg := formatArgs(args...)
 
-	*err = &AdaptErr{Msg: msg, Err: e}
+	switch res := out.(type) {
+	case *error:
+		// return a wrapper err
+		*res = &adaptErr{Msg: msg, Err: e}
+	case *int:
+		if e.Rc == 0 {
+			// we had an adaptErr panic but no Rc
+			log.Println(e)
+			*res = 1
+		}
+		log.Println(e.Msg)
+		*res = e.Rc
+	}
 }
 
 func ExitIf(err, target error, args ...interface{}) {
 	// fmt.Printf("%T %T\n", err, target)
 	if errors.Is(err, target) {
 		rc := int(syscall.EPERM)
-		stack := ErrStack(err)
+		stack := errStack(err)
 		// fmt.Printf("%#v\n", stack)
 		root := stack[0]
 		parent := err
@@ -107,20 +119,24 @@ func ExitIf(err, target error, args ...interface{}) {
 		if ok {
 			rc = int(errno)
 		}
+
 		msg := formatArgs(args...)
 		if len(msg) > 0 {
-			fmt.Printf("%s: ", msg)
+			msg = fmt.Sprintf("%s: ", msg)
 		}
-		fmt.Printf("%v\n", parent)
-		os.Exit(rc)
+		msg = fmt.Sprintf("%v", parent)
+
+		_, file, line, _ := runtime.Caller(1)
+		e := adaptErr{file, line, msg, parent, rc}
+		panic(&e)
 	}
 }
 
-func ErrStack(e error) (stack []error) {
+func errStack(e error) (stack []error) {
 	stack = append(stack, e)
 	child := errors.Unwrap(e)
 	if child != nil {
-		stack = append(ErrStack(child), stack...)
+		stack = append(errStack(child), stack...)
 	}
 	return
 }

main_test.go

@@ -1,4 +1,4 @@
-package adapt
+package goadapt
 
 import (
 	"bytes"
@@ -154,8 +154,8 @@ func TestUnwrap(t *testing.T) {
 loop:
 	for i := 0; i < 10; i++ {
 		switch y := x.(type) {
-		case *AdaptErr:
-			// fmt.Printf("%d AdaptErr x %T y %T\n", i, x, y)
+		case *adaptErr:
+			// fmt.Printf("%d adaptErr x %T y %T\n", i, x, y)
 			x = y.Unwrap()
 		case *miderr:
 			// fmt.Printf("%d miderr x %T y %T\n", i, x, y)
@@ -168,8 +168,8 @@ loop:
 		}
 	}
 
-	var e *AdaptErr
-	tassert(t, errors.As(err, &e), "err not unwrapping to AdaptErr")
+	var e *adaptErr
+	tassert(t, errors.As(err, &e), "err not unwrapping to adaptErr")
 
 	var l *miderr
 	tassert(t, errors.As(err, &l), "err %T not unwrapping to miderr: %v", err, err)