Make PragmaScope a no-op for empty warning lists to prevent global warning suppression leakage

[Copilot]

PragmaScope previously emitted bare #pragma warning disable/restore when given an empty warning list, which in C# applies to all warnings. In nested scopes, this could both over-suppress diagnostics inside the inner scope and prematurely restore warnings in an enclosing scope.

• Behavioral change: empty warnings are now no-op

  • PragmaScope now skips emitting directives when warnings is null/empty/whitespace.
  • This preserves enclosing suppression state and avoids accidental global suppression.

• API contract documentation

  • Updated PragmaScope XML docs on the warnings parameter to explicitly define empty/whitespace input as no-op behavior.

• Regression coverage

  • Added tests for:
    • empty string input (new PragmaScope(cb, ""))
    • empty sequence input (new PragmaScope(cb, [])) nested inside an outer pragma scope
  • The nested case verifies the outer CS1591 suppression remains active until its own scope closes.

using (new PragmaScope(cb, "CS1591"))
{
    using (new PragmaScope(cb, [])) // now no-op
    {
        cb.WriteLine("public int X;");
    }

    cb.WriteLine("public int Y;"); // still under CS1591 suppression
}

• Fixes PragmaScope with an empty warning list emits a bare disable/restore, silently suppressing all warnings and clobbering an enclosing scope #97

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

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