Remove go1.12 support (#2679)

* Revert "Adding ppc64le architecture support on travis-ci (#2538)"

This reverts commit fca3f95d7c.

* not support go1.12

* fix

* Update errors_test.go

* Update debug.go

errors_test.go

@@ -6,6 +6,7 @@ package gin
 
 import (
 	"errors"
+	"fmt"
 	"testing"
 
 	"github.com/gin-gonic/gin/internal/json"
@@ -104,3 +105,24 @@ Error #03: third
 	assert.Nil(t, errs.JSON())
 	assert.Empty(t, errs.String())
 }
+
+type TestErr string
+
+func (e TestErr) Error() string { return string(e) }
+
+// TestErrorUnwrap tests the behavior of gin.Error with "errors.Is()" and "errors.As()".
+// "errors.Is()" and "errors.As()" have been added to the standard library in go 1.13.
+func TestErrorUnwrap(t *testing.T) {
+	innerErr := TestErr("somme error")
+
+	// 2 layers of wrapping : use 'fmt.Errorf("%w")' to wrap a gin.Error{}, which itself wraps innerErr
+	err := fmt.Errorf("wrapped: %w", &Error{
+		Err:  innerErr,
+		Type: ErrorTypeAny,
+	})
+
+	// check that 'errors.Is()' and 'errors.As()' behave as expected :
+	assert.True(t, errors.Is(err, innerErr))
+	var testErr TestErr
+	assert.True(t, errors.As(err, &testErr))
+}