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C#: Guard against AssociatedSymbol not being an IEventSymbol

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Apply same logic as for property/indexer accessors to account for cases where
the associated event cannot be determined. I have not been able to reproduce
such cases locally, though we have seen reports of it happening.
This commit is contained in:
Tom Hvitved
2022-01-27 14:50:04 +01:00
parent d9a1046e0e
commit cdfe239016
3 changed files with 41 additions and 49 deletions
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41
csharp/extractor/Semmle.Extraction.CSharp/Entities/EventAccessor.cs
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@@ -3,45 +3,46 @@ using System.IO;
namespace Semmle.Extraction.CSharp.Entities
{
internal class EventAccessor : Accessor
internal class EventAccessor : Method
{
private EventAccessor(Context cx, IMethodSymbol init)
: base(cx, init) { }
private readonly IEventSymbol @event;
private EventAccessor(Context cx, IMethodSymbol init, IEventSymbol @event)
: base(cx, init)
{
this.@event = @event;
}
/// <summary>
/// Gets the event symbol associated with this accessor.
/// Gets the event symbol associated with accessor `symbol`, or `null`
/// if there is no associated symbol.
/// </summary>
private IEventSymbol? EventSymbol => Symbol.AssociatedSymbol as IEventSymbol;
public static IEventSymbol? GetEventSymbol(IMethodSymbol symbol) =>
symbol.AssociatedSymbol as IEventSymbol;
public override void Populate(TextWriter trapFile)
{
PopulateMethod(trapFile);
ContainingType!.PopulateGenerics();
var @event = EventSymbol;
if (@event is null)
{
var type = Symbol.AssociatedSymbol?.GetType().ToString() ?? "null";
Context.ModelError(Symbol, $"Unhandled event accessor associated symbol of type {type}");
return;
}
var parent = Event.Create(Context, @event);
int kind;
EventAccessor unboundAccessor;
if (SymbolEqualityComparer.Default.Equals(Symbol, @event.AddMethod))
{
kind = 1;
unboundAccessor = Create(Context, @event.OriginalDefinition.AddMethod!);
var orig = @event.OriginalDefinition;
unboundAccessor = Create(Context, orig.AddMethod!, orig);
}
else if (SymbolEqualityComparer.Default.Equals(Symbol, @event.RemoveMethod))
{
kind = 2;
unboundAccessor = Create(Context, @event.OriginalDefinition.RemoveMethod!);
var orig = @event.OriginalDefinition;
unboundAccessor = Create(Context, orig.RemoveMethod!, orig);
}
else
{
Context.ModelError(Symbol, "Undhandled event accessor kind");
Context.ModelError(Symbol, $"Undhandled event accessor kind {Symbol.ToDisplayString()}");
return;
}
@@ -53,14 +54,14 @@ namespace Semmle.Extraction.CSharp.Entities
Overrides(trapFile);
}
public static new EventAccessor Create(Context cx, IMethodSymbol symbol) =>
EventAccessorFactory.Instance.CreateEntityFromSymbol(cx, symbol);
public static EventAccessor Create(Context cx, IMethodSymbol symbol, IEventSymbol @event) =>
EventAccessorFactory.Instance.CreateEntity(cx, symbol, (symbol, @event));
private class EventAccessorFactory : CachedEntityFactory<IMethodSymbol, EventAccessor>
private class EventAccessorFactory : CachedEntityFactory<(IMethodSymbol, IEventSymbol), EventAccessor>
{
public static EventAccessorFactory Instance { get; } = new EventAccessorFactory();
public override EventAccessor Create(Context cx, IMethodSymbol init) => new EventAccessor(cx, init);
public override EventAccessor Create(Context cx, (IMethodSymbol, IEventSymbol) init) => new EventAccessor(cx, init.Item1, init.Item2);
}
}
}