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Merged
akeit0 merged 1 commit into from
Oct 10, 2026
Merged

Restore hooks after frame setup failures #354

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64 changes: 37 additions & 27 deletions src/Lua/Runtime/LuaVirtualMachine.Debug.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -87,16 +87,16 @@ static async ValueTask<int> Impl(VirtualMachineExecutionContext context)
stack.Push("line");
stack.Push(line);
context.State.IsInHook = true;
var frame = context.State.CreateCallStackFrame(hook, 2, top, pc);
context.State.PushCallStackFrame(frame);
LuaFunctionExecutionContext funcContext = new()
{
State = context.State,
ArgumentCount = stack.Count - frame.Base,
ReturnFrameBase = frame.ReturnBase,
};
try
{
var frame = context.State.CreateCallStackFrame(hook, 2, top, pc);
context.State.PushCallStackFrame(frame);
LuaFunctionExecutionContext funcContext = new()
{
State = context.State,
ArgumentCount = stack.Count - frame.Base,
ReturnFrameBase = frame.ReturnBase,
};
await hook.Func(funcContext, context.CancellationToken);
}
finally
Expand Down Expand Up @@ -157,22 +157,28 @@ internal static async ValueTask<int> ExecuteCallHook(

stack.Push(LuaValue.Nil);
context.State.IsInHook = true;
var frame = context.State.CreateCallStackFrame(hook, 2, top, 0);
context.State.PushCallStackFrame(frame);
LuaFunctionExecutionContext funcContext = new()
{
State = context.State,
ArgumentCount = stack.Count - frame.Base,
ReturnFrameBase = frame.ReturnBase,
};
var framePushed = false;
try
{
var frame = context.State.CreateCallStackFrame(hook, 2, top, 0);
context.State.PushCallStackFrame(frame);
framePushed = true;
LuaFunctionExecutionContext funcContext = new()
{
State = context.State,
ArgumentCount = stack.Count - frame.Base,
ReturnFrameBase = frame.ReturnBase,
};
await hook.Func(funcContext, cancellationToken);
}
finally
{
context.State.IsInHook = false;
context.State.PopCallStackFrameWithStackPop();
// A failed push leaves the caller's frame on top; do not pop it.
if (framePushed)
{
context.State.PopCallStackFrameWithStackPop();
}
}
}

Expand Down Expand Up @@ -200,23 +206,27 @@ internal static async ValueTask<int> ExecuteCallHook(
stack.Push("return");
stack.Push(LuaValue.Nil);
context.State.IsInHook = true;
frame = context.State.CreateCallStackFrame(hook, 2, top, 0);
context.State.PushCallStackFrame(frame);
LuaFunctionExecutionContext funcContext = new()
{
State = context.State,
ArgumentCount = stack.Count - frame.Base,
ReturnFrameBase = frame.ReturnBase,
};
var framePushed = false;
try
{
context.State.IsInHook = true;
frame = context.State.CreateCallStackFrame(hook, 2, top, 0);
context.State.PushCallStackFrame(frame);
framePushed = true;
LuaFunctionExecutionContext funcContext = new()
{
State = context.State,
ArgumentCount = stack.Count - frame.Base,
ReturnFrameBase = frame.ReturnBase,
};
await hook.Func(funcContext, cancellationToken);
}
finally
{
context.State.IsInHook = false;
context.State.PopCallStackFrameWithStackPop();
if (framePushed)
{
context.State.PopCallStackFrameWithStackPop();
}
}

return r;
Expand Down
26 changes: 16 additions & 10 deletions src/Lua/Standard/DebugLibrary.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -480,29 +480,35 @@ CancellationToken cancellationToken
return 0;
}

if (state.IsReturnHookEnabled && context.State == state)
// Re-arming a hook must not dispatch another hook while its callback is running.
if (state.IsReturnHookEnabled && context.State == state && !state.IsInHook)
{
var stack = state.Stack;
var top = stack.Count;
stack.Push("return");
stack.Push(LuaValue.Nil);
context.State.IsInHook = true;
var frame = context.State.CreateCallStackFrame(hook, 2, top, 0);
context.State.PushCallStackFrame(frame);
LuaFunctionExecutionContext funcContext = new()
{
State = context.State,
ArgumentCount = stack.Count - frame.Base,
ReturnFrameBase = frame.ReturnBase,
};
var framePushed = false;
try
{
var frame = context.State.CreateCallStackFrame(hook, 2, top, 0);
context.State.PushCallStackFrame(frame);
framePushed = true;
LuaFunctionExecutionContext funcContext = new()
{
State = context.State,
ArgumentCount = stack.Count - frame.Base,
ReturnFrameBase = frame.ReturnBase,
};
await hook.Func(funcContext, cancellationToken);
}
finally
{
context.State.IsInHook = false;
context.State.PopCallStackFrameWithStackPop();
if (framePushed)
{
context.State.PopCallStackFrameWithStackPop();
}
}
}

Expand Down
165 changes: 145 additions & 20 deletions tests/Lua.Tests/HookTests.cs
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Original file line number Diff line number Diff line change
@@ -1,30 +1,39 @@
using Lua.Standard;

namespace Lua.Tests;

public class HookTests
{
const string Loop = "local x=0 for i=1,100 do x=x+i end return x";

[TestCase(false, "runtime")]
[TestCase(true, "runtime")]
[TestCase(false, "host")]
[TestCase(true, "host")]
[TestCase(false, "cancel")]
[TestCase(true, "cancel")]
public async Task CountHook_AfterException_StateCanRunHooksAgain(
bool asynchronous,
string failure
[Test]
[Combinatorial]
public async Task Hook_AfterException_StateCanRunHooksAgain(
[Values(false, true)] bool asynchronous,
[Values("runtime", "host", "cancel")] string failure,
[Values("count", "line", "call", "return", "sethook-return")] string hookEvent
)
{
using var state = LuaState.Create();
using var cancellation = new CancellationTokenSource();
var gate = new TaskCompletionSource(TaskCreationOptions.RunContinuationsAsynchronously);
state.SetHook(
new("abort", (c, ct) => asynchronous ? ThrowAsync(c, ct) : Throw(c, ct)),
"",
4
var hook = new LuaFunction(
"abort",
(c, ct) => asynchronous ? ThrowAsync(c, ct) : Throw(c, ct)
);
var source = Loop;
if (hookEvent == "sethook-return")
{
state.OpenDebugLibrary();
state.Environment["abort"] = hook;
source = "debug.sethook(abort, 'r') " + Loop;
}
else
{
state.SetHook(hook, GetMask(hookEvent), hookEvent == "count" ? 4 : 0);
}

var execution = state.DoStringAsync(Loop, "hook.lua", cancellation.Token).AsTask();
var execution = state.DoStringAsync(source, "hook.lua", cancellation.Token).AsTask();
if (asynchronous)
{
Assert.That(execution.IsCompleted, Is.False);
Expand All @@ -33,7 +42,18 @@ string failure

if (failure == "cancel")
{
Assert.ThrowsAsync<LuaCanceledException>(async () => await execution);
if (hookEvent is "call" or "return")
{
Assert.ThrowsAsync<OperationCanceledException>(async () => await execution);
}
else
{
Assert.ThrowsAsync<LuaCanceledException>(async () => await execution);
}
}
else if (failure == "host" && hookEvent is "call" or "return")
{
Assert.ThrowsAsync<InvalidOperationException>(async () => await execution);
}
else
{
Expand Down Expand Up @@ -96,13 +116,51 @@ async ValueTask<int> ThrowAsync(LuaFunctionExecutionContext context, Cancellatio
}
}

[Test]
public async Task CountHook_WhenFrameLimitIsExceeded_StateCanRunHooksAgain()
[TestCase("count", 1)]
[TestCase("line", 1)]
[TestCase("call", 1)]
[TestCase("return", 1)]
[TestCase("sethook-return", 2)]
public async Task Hook_WhenFrameLimitIsExceeded_StateCanRunHooksAgain(
string hookEvent,
int depth
)
{
using var state = LuaState.Create();
state.MaxCallDepth = 1;
state.SetHook(new((c, ct) => new(c.Return())), "", 4);
Assert.ThrowsAsync<LuaRuntimeException>(async () => await state.DoStringAsync(Loop));
state.MaxCallDepth = depth;
var abortedFires = 0;
var hook = new LuaFunction(
(c, ct) =>
{
abortedFires++;
return new(c.Return());
}
);
var source = Loop;
if (hookEvent == "sethook-return")
{
state.OpenDebugLibrary();
state.Environment["abort"] = hook;
source = "debug.sethook(abort, 'r') " + Loop;
}
else
{
state.SetHook(hook, GetMask(hookEvent), hookEvent == "count" ? 4 : 0);
}

if (hookEvent is "call" or "return")
{
Assert.ThrowsAsync<LuaStackOverflowException>(async () =>
await state.DoStringAsync(source)
);
}
else
{
Assert.ThrowsAsync<LuaRuntimeException>(async () => await state.DoStringAsync(source));
}
Assert.That(abortedFires, Is.Zero);
Assert.That(state.CallStackFrameCount, Is.Zero);
var stackTop = state.Stack.Count;

state.MaxCallDepth = 10;
var fires = 0;
Expand All @@ -120,6 +178,73 @@ public async Task CountHook_WhenFrameLimitIsExceeded_StateCanRunHooksAgain()
var result = await state.DoStringAsync(Loop);
Assert.That(result[0], Is.EqualTo((LuaValue)5050));
Assert.That(fires, Is.GreaterThan(0));
Assert.That(state.CallStackFrameCount, Is.Zero);
Assert.That(state.Stack.Count, Is.EqualTo(stackTop));
}

static string GetMask(string hookEvent) =>
hookEvent switch
{
"line" => "l",
"call" => "c",
"return" => "r",
_ => "",
};

[TestCase(false)]
[TestCase(true)]
public async Task DebugSetHook_InsideHook_DoesNotRecursivelyFireReturnHook(bool asynchronous)
{
using var state = LuaState.Create();
state.OpenDebugLibrary();
var gate = new TaskCompletionSource(TaskCreationOptions.RunContinuationsAsynchronously);
var replacementFires = 0;
state.Environment["replacement"] = new LuaFunction(
(c, ct) =>
{
replacementFires++;
return new(c.Return());
}
);
state.Environment["echo"] = new LuaFunction((c, ct) => new(c.Return(c.GetArgument(0))));
var originalFires = 0;
state.SetHook(
new(
async (c, ct) =>
{
originalFires++;
if (asynchronous)
{
await gate.Task;
}
var result = await state.DoStringAsync(
"debug.sethook(replacement, 'r') return 7",
"rearm.lua",
ct
);
Assert.That(result[0], Is.EqualTo((LuaValue)7));
Assert.That(replacementFires, Is.Zero);
return c.Return();
}
),
"",
4
);

var execution = state
.DoStringAsync("local x=0 for i=1,100 do x=x+i end echo(x) return x")
.AsTask();
if (asynchronous)
{
Assert.That(execution.IsCompleted, Is.False);
gate.SetResult();
}
var result = await execution;
Assert.That(result[0], Is.EqualTo((LuaValue)5050));
Assert.That(originalFires, Is.EqualTo(1));
Assert.That(replacementFires, Is.GreaterThan(0));
Assert.That(state.CallStackFrameCount, Is.Zero);
Assert.That(state.Stack.Count, Is.Zero);
}

[TestCase(false)]
Expand Down
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