more nuanced error typing

vilmibm · vilmibm · commit eb403a3b1e99 · 2020-03-27T11:35:39.000-05:00
diff --git a/git/git.go b/git/git.go
@@ -29,10 +29,12 @@ func CurrentBranch() (string, error) {
 		return firstLine(output), nil
 	}
 
-	ce := err.(*run.CmdError)
-	if ce.Stderr.Len() == 0 {
-		// Detached head
-		return "", errors.New("git: not on any branch")
+	var cmdErr *run.CmdError
+	if errors.As(err, &cmdErr) {
+		if cmdErr.Stderr.Len() == 0 {
+			// Detached head
+			return "", errors.New("git: not on any branch")
+		}
 	}
 
 	// Unknown error
diff --git a/test/helpers.go b/test/helpers.go
@@ -14,7 +14,7 @@ import (
 // OutputStub implements a simple utils.Runnable
 type OutputStub struct {
 	Out   []byte
-	Error *run.CmdError
+	Error error
 }
 
 func (s OutputStub) Output() ([]byte, error) {
@@ -49,6 +49,7 @@ func (cs *CmdStubber) Stub(desiredOutput string) {
 }
 
 func (cs *CmdStubber) StubError(errText string) {
+	// TODO support error types beyond CmdError
 	stderrBuff := bytes.NewBufferString(errText)
 	args := []string{"stub"} // TODO make more real?
 	err := errors.New(errText)

Original file line number	Diff line number	Diff line change
`@@ -14,7 +14,7 @@ import (`
`14`	`14`	`// OutputStub implements a simple utils.Runnable`
`15`	`15`	`type OutputStub struct {`
`16`	`16`	`Out []byte`
`17`		`- Error *run.CmdError`
	`17`	`+ Error error`
`18`	`18`	`}`
`19`	`19`
`20`	`20`	`func (s OutputStub) Output() ([]byte, error) {`
`@@ -49,6 +49,7 @@ func (cs *CmdStubber) Stub(desiredOutput string) {`
`49`	`49`	`}`
`50`	`50`
`51`	`51`	`func (cs *CmdStubber) StubError(errText string) {`
	`52`	`+ // TODO support error types beyond CmdError`
`52`	`53`	`stderrBuff := bytes.NewBufferString(errText)`
`53`	`54`	`args := []string{"stub"} // TODO make more real?`
`54`	`55`	`err := errors.New(errText)`