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fix: forward template cancellation tokens #468

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Merged
JerrettDavis merged 1 commit into from
May 31, 2026
Merged

fix: forward template cancellation tokens #468

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24 changes: 18 additions & 6 deletions src/PatternKit.Generators/TemplateGenerator.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -566,7 +566,9 @@ private string GenerateTemplateMethod(
}
else
{
sb.AppendLine($" {hook.Method.Name}(ctx);");
var hasCt = hook.Method.Parameters.Any(IsCancellationToken);
var args = hasCt ? "ctx, ct" : "ctx";
sb.AppendLine($" {hook.Method.Name}({args});");
Comment on lines +569 to +571
}
}

Expand All @@ -588,7 +590,9 @@ private string GenerateTemplateMethod(
}
else
{
sb.AppendLine($" {step.Method.Name}(ctx);");
var hasCt = step.Method.Parameters.Any(IsCancellationToken);
var args = hasCt ? "ctx, ct" : "ctx";
sb.AppendLine($" {step.Method.Name}({args});");
}
}

Expand All @@ -604,7 +608,9 @@ private string GenerateTemplateMethod(
}
else
{
sb.AppendLine($" {hook.Method.Name}(ctx);");
var hasCt = hook.Method.Parameters.Any(IsCancellationToken);
var args = hasCt ? "ctx, ct" : "ctx";
sb.AppendLine($" {hook.Method.Name}({args});");
}
}

Expand All @@ -624,7 +630,9 @@ private string GenerateTemplateMethod(
}
else
{
sb.AppendLine($" {hook.Method.Name}(ctx, ex);");
var hasCt = hook.Method.Parameters.Any(IsCancellationToken);
var args = hasCt ? "ctx, ex, ct" : "ctx, ex";
sb.AppendLine($" {hook.Method.Name}({args});");
}
}

Expand All @@ -649,7 +657,9 @@ private string GenerateTemplateMethod(
}
else
{
sb.AppendLine($" {step.Method.Name}(ctx);");
var hasCt = step.Method.Parameters.Any(IsCancellationToken);
var args = hasCt ? "ctx, ct" : "ctx";
sb.AppendLine($" {step.Method.Name}({args});");
}
}

Expand All @@ -665,7 +675,9 @@ private string GenerateTemplateMethod(
}
else
{
sb.AppendLine($" {hook.Method.Name}(ctx);");
var hasCt = hook.Method.Parameters.Any(IsCancellationToken);
var args = hasCt ? "ctx, ct" : "ctx";
sb.AppendLine($" {hook.Method.Name}({args});");
}
}
}
Expand Down
140 changes: 140 additions & 0 deletions test/PatternKit.Generators.Tests/TemplateGeneratorTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -1068,5 +1068,145 @@ public partial class ImportWorkflow
ScenarioExpect.True(emit.Success, string.Join("\n", emit.Diagnostics));
}

[Scenario("CancellationToken Sync Template Members AreForwardedInAsyncWrapper")]
[Fact]
public void CancellationToken_Sync_Template_Members_AreForwardedInAsyncWrapper()
{
var source = """
using PatternKit.Generators.Template;
using System;
using System.Threading;

namespace PatternKit.Examples;

public sealed class ImportContext
{
public int Count { get; set; }
}

[Template(ErrorPolicy = TemplateErrorPolicy.Rethrow)]
public partial class ImportWorkflow
{
[TemplateHook(HookPoint.BeforeAll)]
private void Open(ImportContext ctx, CancellationToken ct) => ctx.Count++;

[TemplateStep(0)]
private void Validate(ImportContext ctx, CancellationToken ct) => ctx.Count++;

[TemplateHook(HookPoint.AfterAll)]
private void Close(ImportContext ctx, CancellationToken ct) => ctx.Count++;

[TemplateHook(HookPoint.OnError)]
private void CaptureError(ImportContext ctx, Exception ex, CancellationToken ct) => ctx.Count--;
}
""";

var comp = RoslynTestHelpers.CreateCompilation(
source,
assemblyName: nameof(CancellationToken_Sync_Template_Members_AreForwardedInAsyncWrapper));

var gen = new TemplateGenerator();
_ = RoslynTestHelpers.Run(comp, gen, out var run, out var updated);

ScenarioExpect.All(run.Results, r => ScenarioExpect.Empty(r.Diagnostics));

var generated = run.Results
.SelectMany(r => r.GeneratedSources)
.Single(gs => gs.HintName == "ImportWorkflow.Template.g.cs")
.SourceText.ToString();

ScenarioExpect.Contains("public async System.Threading.Tasks.ValueTask ExecuteAsync", generated);
ScenarioExpect.Contains("Open(ctx, ct);", generated);
ScenarioExpect.Contains("Validate(ctx, ct);", generated);
ScenarioExpect.Contains("Close(ctx, ct);", generated);
ScenarioExpect.Contains("CaptureError(ctx, ex, ct);", generated);

var emit = updated.Emit(Stream.Null);
ScenarioExpect.True(emit.Success, string.Join("\n", emit.Diagnostics));
}

[Scenario("CancellationToken Async Template WithoutErrorHooks ForwardsAfterAllTokens")]
[Fact]
public void CancellationToken_Async_Template_WithoutErrorHooks_ForwardsAfterAllTokens()
{
var source = """
using PatternKit.Generators.Template;
using System.Threading;
using System.Threading.Tasks;

namespace PatternKit.Examples;

public sealed class ImportContext
{
public int Count { get; set; }
}

[Template]
public partial class ImportWorkflow
{
[TemplateStep(0)]
private void Validate(ImportContext ctx, CancellationToken ct) => ctx.Count++;

[TemplateHook(HookPoint.AfterAll)]
private ValueTask FlushAsync(ImportContext ctx, CancellationToken ct) => ValueTask.CompletedTask;

[TemplateHook(HookPoint.AfterAll)]
private void Close(ImportContext ctx, CancellationToken ct) => ctx.Count++;
}
""";

var comp = RoslynTestHelpers.CreateCompilation(
source,
assemblyName: nameof(CancellationToken_Async_Template_WithoutErrorHooks_ForwardsAfterAllTokens));

var gen = new TemplateGenerator();
_ = RoslynTestHelpers.Run(comp, gen, out var run, out var updated);

ScenarioExpect.All(run.Results, r => ScenarioExpect.Empty(r.Diagnostics));

var generated = run.Results
.SelectMany(r => r.GeneratedSources)
.Single(gs => gs.HintName == "ImportWorkflow.Template.g.cs")
.SourceText.ToString();

ScenarioExpect.Contains("Validate(ctx, ct);", generated);
ScenarioExpect.Contains("await FlushAsync(ctx, ct).ConfigureAwait(false);", generated);
ScenarioExpect.Contains("Close(ctx, ct);", generated);
ScenarioExpect.DoesNotContain("catch (System.Exception ex)", generated);

var emit = updated.Emit(Stream.Null);
ScenarioExpect.True(emit.Success, string.Join("\n", emit.Diagnostics));
}

[Scenario("Reports Error When Template Step HasNoContextParameter")]
[Fact]
public void Reports_Error_When_Template_Step_HasNoContextParameter()
{
var source = """
using PatternKit.Generators.Template;

namespace PatternKit.Examples;

[Template]
public partial class ImportWorkflow
{
[TemplateStep(0)]
private void Validate()
{
}
}
""";

var comp = RoslynTestHelpers.CreateCompilation(
source,
assemblyName: nameof(Reports_Error_When_Template_Step_HasNoContextParameter));

var gen = new TemplateGenerator();
_ = RoslynTestHelpers.Run(comp, gen, out var run, out _);

var diagnostics = run.Results.SelectMany(r => r.Diagnostics).ToArray();
ScenarioExpect.Contains(diagnostics, d => d.Id == "PKTMP004" && d.GetMessage().Contains("Validate"));
}

#endregion
}
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