fix: report one error text when a response body is too large

docs/configuration.md

@@ -177,7 +177,7 @@ The value is a whole number of bytes, with or without a unit: `B`, `KB`, `MB`, `
 
 **Examples:** `1048576`, `10MiB`, `2MB`, `512KiB`
 
-A server can declare a `Content-Length` far larger than it sends, and the body is allocated from that declared length, so without a limit a single response can exhaust memory. A response above the limit fails with `body size exceeds the given limit` and is counted like any other error.
+A server can declare a `Content-Length` far larger than it sends, and the body is allocated from that declared length, so without a limit a single response can exhaust memory. A response above the limit fails with `response body exceeds the body limit` and is counted like any other error.
 
 The limit applies per response in flight, and a declared Content-Length is allocated up to it, so the worst case is a few times the limit times the concurrency. It covers the requests scripts make as well.
 

internal/sarin/scripthttp.go

@@ -159,7 +159,7 @@ func (c *scriptHTTPClient) Do(r *script.HTTPRequest) (*script.HTTPResponse, erro
 	}
 	if err != nil {
 		if errors.Is(err, fasthttp.ErrBodyTooLarge) {
-			err = types.ErrScriptHTTPBodyTooLarge
+			err = types.ErrResponseBodyTooLarge
 		}
 		return nil, types.NewScriptHTTPRequestError(r.Method, r.URL, err)
 	}

internal/sarin/worker.go

@@ -35,6 +35,10 @@ func statusCodeToString(code int) string {
 
 // responseErrorKey drops the local address, whose port would mint a stats entry per connection.
 func responseErrorKey(err error) string {
+	if errors.Is(err, fasthttp.ErrBodyTooLarge) {
+		return types.ErrResponseBodyTooLarge.Error()
+	}
+
 	message := err.Error()
 
 	var opErr *net.OpError

internal/types/errors.go

@@ -17,6 +17,8 @@ var (
 	)
 
 	ErrRemoteFileTooLarge = errors.New("remote file exceeds " + FormatByteSize(RemoteFetchLimit))
+
+	ErrResponseBodyTooLarge = errors.New("response body exceeds the body limit")
 )
 
 type FieldParseError struct {
@@ -415,7 +417,6 @@ var (
 	ErrScriptHTTPMethodEmpty       = errors.New("http method cannot be empty")
 	ErrScriptHTTPURLInvalid        = errors.New("URL must be an absolute http or https URL")
 	ErrScriptHTTPUnknownOption     = errors.New("unknown option")
-	ErrScriptHTTPBodyTooLarge      = errors.New("response body exceeds the body limit")
 	ErrScriptJSONCycle             = errors.New("cannot encode a table that contains itself")
 )