stride3d/stride · warning · LexerException

Warning at

Error message

Warning at {line}:{column}: {msg}

What it means

Source.warning() emits preprocessor warnings: escalated to error() when werror is set, routed to listener.handleWarning() if a listener exists, and otherwise thrown as LexerException("Warning at line:column: msg"). This is the Source-level counterpart of Preprocessor.warning().

Solutions

1. Attach a PreprocessorListener so warnings go to handleWarning
2. Turn off werror if warnings should stay non-fatal
3. Fix the construct in the shader source flagged at line:column
4. Catch LexerException at the preprocessing call site

Example fix

// before
var lexer = new FileLexer(file); // no listener
// after
var lexer = new FileLexer(file);
lexer.setListener(new MyListener());

if (werror && !suppressWarnings) error(line, column, msg); else warn(line, column, msg);

try { Process(lexer); } catch (LexerException e) when (e.Message.StartsWith("Warning at ")) { log.Warn($"Preprocessor warning (fatal, no listener): {e.Message}"); }

When it happens

Trigger: A Lexer/Source subclass (e.g. skipline paths) diagnoses a warning condition with no listener installed, or with werror enabled turning it fatal.

Common situations: Direct use of individual lexer Source objects rather than the top-level Preprocessor; scripts parsing GLSL/HLSL without wiring a listener.

Understand the failure class

Background: "Must be a positive integer", "Invalid value", "Unsupported": the invalid-argument-value error family, when a library rejects the value you pass — this error's family across 35 libraries.

Related errors

• Warning at
• {msg}
• Cannot read from
• Cannot redefine name 'defined'
• Bad token

AI-assisted analysis of stride3d/stride@96fad776d2 (2026-09-14). Data as JSON: /api/errors/39f2389053b12ee2. Report an issue: GitHub.

Appendix: source

Thrown at sources/shaders/Stride.Shaders.Parsers/CppNet/Source.cs:293

            }
        }

        protected void error(int line, int column, String msg)
        {
            if(listener != null)
                listener.handleError(this, line, column, msg);
            else
                throw new LexerException("Error at " + line + ":" + column + ": " + msg);
        }

        protected void warning(int line, int column, String msg)
        {
            if(werror)
                error(line, column, msg);
            else if(listener != null)
                listener.handleWarning(this, line, column, msg);
            else
                throw new LexerException("Warning at " + line + ":" + column + ": " + msg);
        }

        public virtual void close()
        {
        }
    }

}

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