added various error messages and warnings

compile_report.go

@@ -27,6 +27,8 @@ var (
 	ColorError      = color.New(color.FgRed, color.Bold)
 	ColorInProgress = color.New(color.FgBlue)
 	ColorDone       = color.New(color.FgGreen, color.Bold)
+
+	ColorWarn = color.New(color.FgYellow, color.Bold)
 )
 
 func (s CompileState) String() string {

main.go

@@ -1,8 +1,10 @@
 package main
 
 import (
+	"errors"
 	"flag"
 	"fmt"
+	"os"
 	"os/exec"
 	"path/filepath"
 	"runtime"
@@ -31,16 +33,34 @@ func main() {
 	var err error
 	flag.Parse()
 
-	if err := FillCompileConfigs(); err != nil {
-		panic(err)
-	}
-
 	ModulePath, err = filepath.Abs(flag.Arg(0))
 	if err != nil {
 		panic(err)
 	}
 	ProjectName = filepath.Base(ModulePath)
 
+	if _, err := exec.LookPath("go"); err != nil {
+		ColorError.Fprintln(os.Stderr, "go not found in PATH. compilation not possible")
+		return
+	}
+
+	if !*NoCompress {
+		if _, err := exec.LookPath("upx"); err != nil {
+			ColorWarn.Fprintln(os.Stderr, "upx not found in PATH. file compression not possible")
+			*NoCompress = true
+		}
+	}
+
+	if err := FillCompileConfigs(); err != nil {
+		ColorError.Fprintln(os.Stderr, fmt.Errorf("target architectures could not be determined: %w", err))
+		return
+	}
+
+	if _, err := os.Stat(filepath.Join(ModulePath, "go.mod")); errors.Is(err, os.ErrNotExist) {
+		ColorError.Fprintf(os.Stderr, "no Go module found at '%s'\n", ModulePath)
+		return
+	}
+
 	ch := make(chan *CompileReport, len(CompileConfigs))
 	wg := new(sync.WaitGroup)