Empty Catch Block

ID

csharp.empty_catch_block

Severity

high

Remediation Complexity

trivial

Remediation Risk

low

Remediation Effort

low

Resource

Reliability

Language

CSharp

Tags

CWE:1069, exception-handling, reliability

Description

Reports catch clauses whose body has no executable statements. An empty catch silently swallows the exception, hiding bugs and leaving the program running in an unexpected state with no log, no rethrow, and no handling.

Rationale

Exceptions exist to signal that something went wrong. A catch block that does nothing discards that signal: the failure leaves no trace, the original stack is lost, and any subsequent code runs as if the operation had succeeded. Bugs that should be loud and reproducible become silent and intermittent.

Comments do not count as handling. A block with only a comment is still empty.

public class Worker
{
    public void Broken()
    {
        try
        {
            Run();
        }
        catch (Exception)        // FLAW — exception is silently swallowed
        {
        }
    }

    public void BrokenCommentOnly()
    {
        try
        {
            Run();
        }
        catch (Exception)        // FLAW — comment is not a handler
        {
            // ignore on purpose
        }
    }

    public void Ok()
    {
        try
        {
            Run();
        }
        catch (Exception ex)     // OK — failure is logged
        {
            Log(ex);
        }
    }
}

Remediation

Decide how the failure should be handled: log it, wrap it in a domain exception, rethrow it, or use a more specific exception type. If the exception genuinely must be ignored, add a statement that documents and enforces that decision (for example a logger call recording the expected scenario), not just a comment.

References