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Fix/user message selection and stdin deadlock #47

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a1dake wants to merge 2 commits into from
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Fix/user message selection and stdin deadlock #47

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b543516
feat: allow selecting user messages in Plain Text mode
a1dake Jul 21, 2026
897d6f4
fix: fix hang on second+ message caused by stdin/stdout pipe deadlock
a1dake Jul 21, 2026
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34 changes: 21 additions & 13 deletions UnrealClaude/Source/UnrealClaude/Private/ClaudeCodeRunner.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1437,21 +1437,29 @@ void FClaudeCodeRunner::ExecuteProcess()
// Cache the stdin payload for the silence watchdog diagnostic.
LastStdinPayload = StdinPayload;

if (!StdinPayload.IsEmpty())
// Write on a background thread
void* WriteHandle = StdInWritePipe;
void* ReadHandleForChild = StdInReadPipe;
StdInWritePipe = nullptr;
StdInReadPipe = nullptr;

Async(EAsyncExecution::Thread, [WriteHandle, ReadHandleForChild, StdinPayload, ImageCount = CurrentConfig.AttachedImagePaths.Num()]()
{
FTCHARToUTF8 Utf8Payload(*StdinPayload);
int32 BytesWritten = 0;
bool bWritten = FPlatformProcess::WritePipe(StdInWritePipe, (const uint8*)Utf8Payload.Get(), Utf8Payload.Length(), &BytesWritten);
UE_LOG(LogUnrealClaude, Log, TEXT("Wrote to Claude stdin (stream-json, success=%d, %d/%d bytes, images: %d, system: %d chars, user: %d chars)"),
bWritten, BytesWritten, Utf8Payload.Length(), CurrentConfig.AttachedImagePaths.Num(),
CurrentConfig.SystemPrompt.Len(), CurrentConfig.Prompt.Len());
}
if (!StdinPayload.IsEmpty())
{
FTCHARToUTF8 Utf8Payload(*StdinPayload);
int32 BytesWritten = 0;
bool bWritten = FPlatformProcess::WritePipe(WriteHandle, (const uint8*)Utf8Payload.Get(), Utf8Payload.Length(), &BytesWritten);
UE_LOG(LogUnrealClaude, Log, TEXT("Wrote to Claude stdin (stream-json, success=%d, %d/%d bytes, images: %d)"),
bWritten, BytesWritten, Utf8Payload.Length(), ImageCount);
}

// Close stdin write pipe to signal EOF to Claude
// We close the entire stdin pipe pair since child has the read end
FPlatformProcess::ClosePipe(StdInReadPipe, StdInWritePipe);
StdInReadPipe = nullptr;
StdInWritePipe = nullptr;
// Close stdin write pipe to signal EOF to Claude
// We close the entire stdin pipe pair since child has the read end
void* ReadCopy = ReadHandleForChild;
void* WriteCopy = WriteHandle;
FPlatformProcess::ClosePipe(ReadCopy, WriteCopy);
});
}

SystemPromptFilePath.Empty();
Expand Down
29 changes: 23 additions & 6 deletions UnrealClaude/Source/UnrealClaude/Private/ClaudeEditorWidget.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -24,6 +24,7 @@
#include "Widgets/Input/SButton.h"
#include "Widgets/Input/SCheckBox.h"
#include "Widgets/SBoxPanel.h"
#include "Widgets/Layout/SWidgetSwitcher.h"
#include "Styling/AppStyle.h"
#include "Styling/CoreStyle.h"
#include "Framework/Application/SlateApplication.h"
Expand Down Expand Up @@ -152,11 +153,27 @@ void SChatMessage::Construct(const FArguments& InArgs)
}
else
{
ContentWidget = SNew(STextBlock)
.Text(FText::FromString(Message))
.TextStyle(FAppStyle::Get(), "NormalText")
.ColorAndOpacity(FSlateColor(TextColor))
.AutoWrapText(true);
// Allow selecting user messages in Plain Text mode
ContentWidget = SNew(SWidgetSwitcher)
.WidgetIndex_Lambda([this]() { return bSelectionModeAttr.Get() ? 1 : 0; })

+ SWidgetSwitcher::Slot()
[
SNew(STextBlock)
.Text(FText::FromString(Message))
.TextStyle(FAppStyle::Get(), "NormalText")
.ColorAndOpacity(FSlateColor(TextColor))
.AutoWrapText(true)
]

+ SWidgetSwitcher::Slot()
[
SNew(SMultiLineEditableText)
.Text(FText::FromString(Message))
.TextStyle(FAppStyle::Get(), "NormalText")
.AutoWrapText(true)
.IsReadOnly(true)
];
}

ChildSlot
Expand Down Expand Up @@ -481,7 +498,7 @@ void SClaudeEditorWidget::AddMessage(const FString& Message, bool bIsUser)
.Message(Message)
.IsUser(bIsUser)
.bRenderMarkdown(!bIsUser) // Enable Markdown rendering for Claude messages
.bSelectionMode_Lambda([this, bIsUser]() { return bSelectionMode && !bIsUser; }) // Dynamic: only for Claude messages
.bSelectionMode_Lambda([this]() { return bSelectionMode; }) // Dynamic: applies to both user and Claude messages
];

// Only scroll to bottom if we were already there
Expand Down