Relax runtime requirement do not fail, print warning (#6017)

main.go

@@ -1,5 +1,5 @@
 /*
- * Minio Cloud Storage, (C) 2016,2017 Minio, Inc.
+ * Minio Cloud Storage, (C) 2016, 2017, 2018 Minio, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -54,8 +54,7 @@ func checkGoVersion(goVersionStr string) error {
 	}
 
 	if !constraint.Check(goVersion) {
-		return fmt.Errorf("Minio is not compiled by Go %s.  Please recompile accordingly",
-			goVersionConstraint)
+		return fmt.Errorf("Minio is not compiled by go %s. Minimum required version is %s, go %s release is known to have security issues. Please recompile accordingly", goVersionConstraint, minGoVersion, runtime.Version()[2:])
 	}
 
 	return nil
@@ -65,7 +64,7 @@ func main() {
 	// When `go get` is used minimum Go version check is not triggered but it would have compiled it successfully.
 	// However such binary will fail at runtime, hence we also check Go version at runtime.
 	if err := checkGoVersion(runtime.Version()[2:]); err != nil {
-		console.Fatalln("Go runtime version check failed.", err)
+		console.Errorln(err)
 	}
 
 	minio.Main(os.Args)

main_test.go

@@ -1,5 +1,5 @@
 /*
- * Minio Cloud Storage, (C) 2017 Minio, Inc.
+ * Minio Cloud Storage, (C) 2017, 2018 Minio, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,34 +17,30 @@
 package main
 
 import (
-	"fmt"
 	"testing"
 )
 
 func TestCheckGoVersion(t *testing.T) {
 	// Test success cases.
 	testCases := []struct {
-		version     string
-		expectedErr error
+		version string
+		success bool
 	}{
-		{minGoVersion, nil},
-		{"1.6.8", fmt.Errorf("Minio is not compiled by Go >= 1.9.4.  Please recompile accordingly")},
-		{"1.5", fmt.Errorf("Minio is not compiled by Go >= 1.9.4.  Please recompile accordingly")},
-		{"0.1", fmt.Errorf("Minio is not compiled by Go >= 1.9.4.  Please recompile accordingly")},
-		{".1", fmt.Errorf("Malformed version: .1")},
-		{"somejunk", fmt.Errorf("Malformed version: somejunk")},
+		{minGoVersion, true},
+		{"1.6.8", false},
+		{"1.5", false},
+		{"0.1", false},
+		{".1", false},
+		{"somejunk", false},
 	}
 
 	for _, testCase := range testCases {
 		err := checkGoVersion(testCase.version)
-		if testCase.expectedErr == nil {
-			if err != nil {
-				t.Fatalf("expected: %v, got: %v", testCase.expectedErr, err)
-			}
-		} else if err == nil {
-			t.Fatalf("expected: %v, got: %v", testCase.expectedErr, err)
-		} else if testCase.expectedErr.Error() != err.Error() {
-			t.Fatalf("expected: %v, got: %v", testCase.expectedErr, err)
+		if err != nil && testCase.success {
+			t.Fatalf("Test %v, expected: success, got: %v", testCase, err)
+		}
+		if err == nil && !testCase.success {
+			t.Fatalf("Test %v, expected: failure, got: success", testCase)
 		}
 	}
 }