Cleanup. Remove unused functions.

Clarify README.md documentation.

Author: mspiegel

README.md

@@ -1,11 +1,5 @@
 # go-multierror
 
-[![Build Status](http://img.shields.io/travis/hashicorp/go-multierror.svg?style=flat-square)][travis]
-[![Go Documentation](http://img.shields.io/badge/go-documentation-blue.svg?style=flat-square)][godocs]
-
-[travis]: https://travis-ci.org/hashicorp/go-multierror
-[godocs]: https://godoc.org/github.com/hashicorp/go-multierror
-
 `go-multierror` is a package for Go that provides a mechanism for
 representing a list of `error` values as a single `error`.
 
@@ -14,16 +8,12 @@ be a list of errors. If the caller knows this, they can unwrap the
 list and access the errors. If the caller doesn't know, the error
 formats to a nice human-readable format.
 
-`go-multierror` implements the
-[errwrap](https://github.com/hashicorp/errwrap) interface so that it can
-be used with that library, as well.
+This is a fork of the hashicorp `go-multierror` library. In this
+fork, nil error values are handled transparently.
 
 ## Installation and Docs
 
-Install using `go get github.com/hashicorp/go-multierror`.
-
-Full documentation is available at
-http://godoc.org/github.com/hashicorp/go-multierror
+Install using `go get github.com/mspiegel/go-multierror`.
 
 ## Usage
 
@@ -38,14 +28,12 @@ if the first argument is nil, a `multierror.Error`, or any other `error`,
 the function behaves as you would expect.
 
 ```go
-var result error
+var err, result error
 
-if err := step1(); err != nil {
-	result = multierror.Append(result, err)
-}
-if err := step2(); err != nil {
-	result = multierror.Append(result, err)
-}
+err = step1()
+result = multierror.Append(result, err)
+err = step2()
+result = multierror.Append(result, err)
 
 return result
 ```
@@ -79,19 +67,4 @@ if err := something(); err != nil {
 		// Use merr.Errors
 	}
 }
-```
-
-**Returning a multierror only if there are errors**
-
-If you build a `multierror.Error`, you can use the `ErrorOrNil` function
-to return an `error` implementation only if there are errors to return:
-
-```go
-var result *multierror.Error
-
-// ... accumulate errors here
-
-// Return the `error` only if errors were added to the multierror, otherwise
-// return nil since there are no errors.
-return result.ErrorOrNil()
-```
+```

multierror.go

@@ -20,21 +20,6 @@ func (e *Error) Error() string {
 	return fn(e.Errors)
 }
 
-// ErrorOrNil returns an error interface if this Error represents
-// a list of errors, or returns nil if the list of errors is empty. This
-// function is useful at the end of accumulation to make sure that the value
-// returned represents the existence of errors.
-func (e *Error) ErrorOrNil() error {
-	if e == nil {
-		return nil
-	}
-	if len(e.Errors) == 0 {
-		return nil
-	}
-
-	return e
-}
-
 func (e *Error) GoString() string {
 	return fmt.Sprintf("*%#v", *e)
 }

multierror_test.go

@@ -43,20 +43,6 @@ func TestErrorError_default(t *testing.T) {
 	}
 }
 
-func TestErrorErrorOrNil(t *testing.T) {
-	err := new(Error)
-	if err.ErrorOrNil() != nil {
-		t.Fatalf("bad: %#v", err.ErrorOrNil())
-	}
-
-	err.Errors = []error{errors.New("foo")}
-	if v := err.ErrorOrNil(); v == nil {
-		t.Fatal("should not be nil")
-	} else if !reflect.DeepEqual(v, err) {
-		t.Fatalf("bad: %#v", v)
-	}
-}
-
 func TestErrorWrappedErrors(t *testing.T) {
 	errors := []error{
 		errors.New("foo"),