fix(cli): handle nil unwrap errors when formatting (#18099)

ethanndickson · web-flow · commit e5c254888a00 · 2025-05-30T11:31:51.000+10:00
Discovered an unhelpful error when running a CLI command without internet (I didn't know I didn't have internet!): ``` $ coder ls Encountered an error running "coder list", see "coder list --help" for more information error: <nil> ``` The source of this was that calling `Unwrap()` on `net.DNSError` can return nil, causing the whole error trace to get replaced by it. Instead, we'll just treat a nil `Unwrap()` return value as if there was nothing to unwrap. The result is: ``` $ coder ls Encountered an error running "coder list", see "coder list --help" for more information error: query workspaces: Get "https://dev.coder.com/api/v2/workspaces?q=owner%3Ame": dial tcp: lookup dev.coder.com: no such host ```
diff --git a/cli/root.go b/cli/root.go
@@ -1060,11 +1060,12 @@ func cliHumanFormatError(from string, err error, opts *formatOpts) (string, bool
 		return formatRunCommandError(cmdErr, opts), true
 	}
 
-	uw, ok := err.(interface{ Unwrap() error })
-	if ok {
-		msg, special := cliHumanFormatError(from+traceError(err), uw.Unwrap(), opts)
-		if special {
-			return msg, special
+	if uw, ok := err.(interface{ Unwrap() error }); ok {
+		if unwrapped := uw.Unwrap(); unwrapped != nil {
+			msg, special := cliHumanFormatError(from+traceError(err), unwrapped, opts)
+			if special {
+				return msg, special
+			}
 		}
 	}
 	// If we got here, that means that the wrapped error chain does not have

Original file line number	Diff line number	Diff line change
`@@ -1060,11 +1060,12 @@ func cliHumanFormatError(from string, err error, opts *formatOpts) (string, bool`
`1060`	`1060`	`return formatRunCommandError(cmdErr, opts), true`
`1061`	`1061`	`}`
`1062`	`1062`
`1063`		`- uw, ok := err.(interface{ Unwrap() error })`
`1064`		`- if ok {`
`1065`		`- msg, special := cliHumanFormatError(from+traceError(err), uw.Unwrap(), opts)`
`1066`		`- if special {`
`1067`		`- return msg, special`
	`1063`	`+ if uw, ok := err.(interface{ Unwrap() error }); ok {`
	`1064`	`+ if unwrapped := uw.Unwrap(); unwrapped != nil {`
	`1065`	`+ msg, special := cliHumanFormatError(from+traceError(err), unwrapped, opts)`
	`1066`	`+ if special {`
	`1067`	`+ return msg, special`
	`1068`	`+ }`
`1068`	`1069`	`}`
`1069`	`1070`	`}`
`1070`	`1071`	`// If we got here, that means that the wrapped error chain does not have`