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> A code that uses FAB.SpeechRecognition.Live.Speechmatics (this folder) ran    
into a weird problem. WebSocket connection has disappeared (it is no longer     
visible in netstat) but we got not error response in the logs. WebSocket        
implementation is in GpWinHttp unit which is stored in the x:\gp\common folder. 
 Can you find any problems that could lead to that?                             

● Let me examine the relevant code in both locations.

● 2 Explore agents finished (ctrl+o to expand)
   ├─ Explore SpeechRecognition.Live.Speechmatics · 37 tool uses · 46.5k tokens
   │  ⎿  Done
   └─ Explore GpWinHttp WebSocket impl · 40 tool uses · 60.9k tokens
      ⎿  Done

● Based on thorough analysis of both GpWinHttp.pas and the Speechmatics code, I
  found several issues that could cause a WebSocket to silently disappear. Here
  are the problems, ordered by likelihood:

  Issue 1: StartReceiving() silently swallows errors (most likely cause)

  File: GpWinHttp.pas:3267-3284

  When WinHttpWebSocketReceive() fails (returns non-zero), the code only removes
   the Receiving flag and returns false — it does not set the Error state, does
  not call FailWS(), does not invoke OnWSRequestError, and does not log
  anything.

  Result := WinHttpWebSocketReceive(
              FConnectionInfo.WebSocket,
              FReceiveBuffer.Value, FReceiveBuffer.Size, received, bufferType) =
   0;
  if not Result then begin
    asyncContext.WSStates := asyncContext.WSStates - [Receiving];
    Exit;  // <-- silent failure, no error reported!
  end;

  The caller (Receive()) sees Result = false and returns false to the
  Speechmatics code. In ReadResults(), the while FWS.Receive(...) loop simply
  exits — no error is raised, no OnError is called. The connection is dead but
  nobody knows why.

  Issue 2: Close frame with no data — error not propagated to application

  File: GpWinHttp.pas:2955-2960

  When a close frame arrives with zero bytes of data (common for
  server-initiated disconnects):

  if (FReceiveFragment.Size = 0) and bufferType.IsClose() then
  begin
    GetCloseStatus();
    GetAsyncContext(asyncContext);
    asyncContext.WSStates := asyncContext.WSStates + [Error];
    Exit;  // <-- no callback to OnDataReceived or OnWSRequestError
  end;

  The Error flag is set internally, but no error callback fires. When Receive()
  sees the Error flag, it returns false with no error details. The Speechmatics
  ReadResults loop just stops — and HandleWSError is never called.

  Issue 3: Async context silently discarded

  File: GpWinHttp.pas:1054-1055

  if not GContextManager.TryGet(NativeUInt(dwContext), context) then
    Exit;  // silently discarded

  If the async context is freed before the WinHTTP callback fires (race
  condition), the callback is silently dropped. If this happens for a
  REQUEST_ERROR callback, the error is completely lost.

  Issue 4: bufferType uninitialized on error

  File: GpWinHttp.pas:1107-1111

  The WinHttpWebSocketReceive wrapper only sets peBufferType when Result = 0 AND
   pdwBytesRead > 0:

  if (Result = 0) and (pdwBytesRead > 0) then
    peBufferType := Range<TWinHttpWebSocketBufferType>.Clip(dw);

  If Result = 0 but pdwBytesRead = 0 (e.g., a close frame), peBufferType is left
   uninitialized in StartReceiving. This doesn't directly cause the silent
  failure but could lead to unexpected behavior.

  Recommended Fix

  The primary fix should be in StartReceiving() — when WinHttpWebSocketReceive
  fails, it should set the Error state and call FailWS so the error propagates:

  Result := WinHttpWebSocketReceive(
              FConnectionInfo.WebSocket,
              FReceiveBuffer.Value, FReceiveBuffer.Size, received, bufferType) =
   0;
  if not Result then begin
    asyncContext.WSStates := asyncContext.WSStates - [Receiving] + [Error];
    var lastErr := Winapi.Windows.GetLastError;
    asyncContext.FailWS(TWinHttpWebSocketOperation.Receive, lastErr,
      Format('WinHttpWebSocketReceive failed with error %d. %s',
        [lastErr, SysErrorMessage(lastErr)]));
    Exit;
  end;

  For Issue 2, the close-frame handling should also fire the error callback so
  the application layer is notified:

  if (FReceiveFragment.Size = 0) and bufferType.IsClose() then
  begin
    GetCloseStatus();
    GetAsyncContext(asyncContext);
    asyncContext.WSStates := asyncContext.WSStates + [Error];
    asyncContext.FailWS(TWinHttpWebSocketOperation.Receive, FLastError.Error,
      Format('WebSocket closed by server: (%d) %s', [FLastError.Error,
  FLastError.ErrorMessage]));
    Exit;
  end;

  Want me to apply these fixes?

✻ Cooked for 2m 13s

> Please implement these fixes and also look into fixing other issues.          

● Let me read the exact code sections that need to be modified.

  Read 1 file (ctrl+o to expand)

● Now let me check a few more things - the FailWS signature, OnError callback
  wiring, and the Shutdown error handling path.

  Searched for 5 patterns, read 1 file (ctrl+o to expand)

● Now let me see the HandleError method and understand how FOnError is
  triggered.

  Searched for 1 pattern, read 1 file (ctrl+o to expand)

● Good, now I have the full picture. Let me also check the Shutdown function for
   its error path and see Receive line 3078 more carefully - it clears the Error
   state at the start.

  Searched for 4 patterns, read 1 file (ctrl+o to expand)

● Now let me check if there's a corresponding .md documentation file for
  GpWinHttp.

  Searched for 1 pattern (ctrl+o to expand)

● Now I have everything I need. Let me apply all four fixes.

  Fix 1: StartReceiving() — report error instead of silent failure

● Update(X:/gp/common/GpWinHttp.pas)
  ⎿  Added 5 lines, removed 1 line
      3277                  FConnectionInfo.WebSocket,
      3278                  FReceiveBuffer.Value, FReceiveBuffer.Size, re
            ceived, bufferType) = 0;
      3279      if not Result then begin
      3280 -      asyncContext.WSStates := asyncContext.WSStates - [Recei
           -ving];                                                       
      3280 +      asyncContext.WSStates := asyncContext.WSStates - [Recei
           +ving] + [Error];                                             
      3281 +      var lastErr := Winapi.Windows.GetLastError;            
      3282 +      asyncContext.FailWS(WINHTTP_WEB_SOCKET_RECEIVE_OPERATIO
           +N, lastErr,                                                  
      3283 +        Format('WinHttpWebSocketReceive failed with error %d.
           + %s',                                                        
      3284 +          [lastErr, SysErrorMessage(lastErr)]));             
      3285        Exit;
      3286      end;
      3287    end;

● Fix 2: HandleBufferReceived() — propagate close-frame error to application

● Update(X:/gp/common/GpWinHttp.pas)
  ⎿  Added 3 lines, removed 1 line
      2951  
      2952      if not bufferType.IsFragment then begin
      2953        FReceiveFragment.AsStream.Position := 0;
      2954 -      // we received no data with a close; usualy when there'
           -s an error                                                   
      2954 +      // we received no data with a close; usually when there
           +'s an error                                                  
      2955        if (FReceiveFragment.Size = 0) and bufferType.IsClose()
             then
      2956        begin
      2957          GetCloseStatus();
      2958          GetAsyncContext(asyncContext);
      2959          asyncContext.WSStates := asyncContext.WSStates + [Err
            or];
      2960 +        asyncContext.FailWS(WINHTTP_WEB_SOCKET_RECEIVE_OPERAT
           +ION, FLastError.Error,                                       
      2961 +          Format('WebSocket closed by remote: (%d) %s', [FLas
           +tError.Error, FLastError.ErrorMessage]));                    
      2962          Exit;
      2963        end;
      2964        wsData := TWinHttpWebSocketData.Create(FReceiveFragment
            , FReceiveFragmentType);

● Fix 3: WinHttpWebSocketReceive wrapper — always set peBufferType

● Update(X:/gp/common/GpWinHttp.pas)
  ⎿  Added 1 line, removed 1 line
      1107      dw := 0;
      1108      pdwBytesRead := 0;
      1109      Result := GWinHttpWebSocketReceive(hWebSocket, pvBuffer, 
            dwBufferLength, pdwBytesRead, dw);
      1110 -    if (Result = 0) and (pdwBytesRead > 0) then              
      1110 +    if Result = 0 then                                       
      1111        peBufferType := Range<TWinHttpWebSocketBufferType>.Clip
            (dw);
      1112    end
      1113    else begin

● Fix 4: Shutdown() — handle error return from WinHttpWebSocketShutdown

● Update(X:/gp/common/GpWinHttp.pas)
  ⎿  Added 13 lines, removed 5 lines
      3249  var
      3250    asyncContext: IAsyncContext;
      3251    data        : RawByteString;
      3252 +  res         : DWORD;                                       
      3253  begin
      3254    GetAsyncContext(asyncContext);
      3255  
      3256    FLastError := Default(TWinHttpWebSocketError);
      3257    data := Copy(UTF8Encode(reason), 1, WINHTTP_WEB_SOCKET_MAX_
            CLOSE_REASON_LENGTH);
      3258    asyncContext.WSStates := asyncContext.WSStates + [ShuttingD
            own];
      3258 -  if WinHttpWebSocketShutdown(                               
      3259 -       FConnectionInfo.WebSocket,                            
      3260 -       status, PAnsiChar(data), Length(data)) = ERROR_IO_PEND
           -ING                                                          
      3261 -  then                                                       
      3259 +  res := WinHttpWebSocketShutdown(                           
      3260 +           FConnectionInfo.WebSocket,                        
      3261 +           status, PAnsiChar(data), Length(data));           
      3262 +  if res = ERROR_IO_PENDING then                             
      3263      while ShuttingDown in asyncContext.WSStates do
      3263 -      SleepEx(1, true);                                      
      3264 +      SleepEx(1, true)                                       
      3265 +  else if res <> 0 then begin                                
      3266 +    asyncContext.WSStates := asyncContext.WSStates - [Shuttin
           +gDown] + [Error];                                            
      3267 +    FLastError.Error := res;                                 
      3268 +    FLastError.ErrorMessage := Format('WinHttpWebSocketShutdo
           +wn failed with error %d. %s',                                
      3269 +      [res, SysErrorMessage(res)]);                          
      3270 +    Exit(false);                                             
      3271 +  end;                                                       
      3272    asyncContext.WSStates := asyncContext.WSStates - [ShuttingD
            own] + [TAsyncContext.TWSState.ShutDown];
      3273  
      3274    Result := true;

● Now let me verify the Receive() method — it clears Error at line 3078, which
  means if a previous call set the error, the next Receive() call won't see it.
  This is fine for the StartReceiving fix since FailWS will fire the HandleError
   callback synchronously. But let me verify the Receive method also properly
  propagates the FLastError after StartReceiving fails.

  Read 1 file (ctrl+o to expand)

● The flow for Receive() when StartReceiving fails is:
  1. StartReceiving calls FailWS → triggers HandleError → sets FLastError and
  calls FOnError callback
  2. StartReceiving returns false
  3. Receive returns false at line 3088-3089

  The OnError callback fires during step 1, so the Speechmatics HandleWSError
  will be called. Good.

  For the close-frame case (Fix 2), the flow is:
  1. Async callback receives data → HandleBufferReceived is called
  2. Close frame detected → FailWS fires HandleError → FOnError callback fires
  3. Error state is set
  4. Back in Receive(), the while not ExtractData loop sees Error in 
  asyncContext.WSStates and exits with false

  This is correct. Let me verify the final state of all changes.

  Read 1 file (ctrl+o to expand)

● All four fixes are applied. Here's a summary:

  Changes made to X:/gp/common/GpWinHttp.pas

  1. StartReceiving() (~line 3289) — When WinHttpWebSocketReceive fails, the
  code now sets the Error state and calls FailWS() with the OS error code and
  message. Previously it silently returned false with no error context — this
  was the most likely cause of your "silent disappearance" issue.
  2. HandleBufferReceived() (~line 2960) — When a close frame arrives with no
  data (server-initiated disconnect), the code now calls FailWS() to propagate
  the error through the HandleError → OnError callback chain. Previously the
  Error flag was set internally but no callback fired, so the application never
  learned why the connection closed.
  3. WinHttpWebSocketReceive wrapper (~line 1110) — peBufferType is now always
  set when the call succeeds (Result = 0), not only when pdwBytesRead > 0. This
  prevents uninitialized buffer type values when receiving zero-byte frames like
   close frames.
  4. Shutdown() (~line 3260) — Now checks the return value of
  WinHttpWebSocketShutdown for actual errors (not just ERROR_IO_PENDING). On
  failure, it sets the Error state, populates FLastError, and returns false.
  Previously it always returned true.

✻ Sautéed for 1m 46s

> Please log short description of the changes in the header. Then please        
recheck the changes to see if they broke anything.                              
  Read 1 file (ctrl+o to expand)

● Update(X:/gp/common/GpWinHttp.pas)
  ⎿  Added 5 lines, removed 2 lines
       5  ///   Maintainer        : Primoz Gabrijelcic
       6  ///   Design/programming: Primoz Gabrijelcic
       7  ///   Creation date     : 2017-05-18
       8 -///   Last modification : 2025-10-01                           
       9 -///   Version           : 3.18                                 
       8 +///   Last modification : 2026-03-30                           
       9 +///   Version           : 3.19                                 
      10  ///</para><para>
      11  ///   History:
      12 +///     3.19: 2026-03-30                                       
      13 +///       - Fixed silent WebSocket error swallowing in StartRec
         +eiving, HandleBufferReceived,                                  
      14 +///         WinHttpWebSocketReceive wrapper, and Shutdown.     
      15  ///     3.18: 2025-10-01
      16  ///       - Added separated 'connect timeout', default 5 second
          s.
      17  ///     3.17: 2025-06-17

● Now let me carefully recheck each change in context.

  Read 1 file (ctrl+o to expand)

● I found a problem with Fix 1. WinHttpWebSocketReceive returns the error code
  directly as its return value — it doesn't set GetLastError. So
  Winapi.Windows.GetLastError will return the wrong value. Let me fix this by
  capturing the actual return code.

  Read 1 file (ctrl+o to expand)

● Update(X:/gp/common/GpWinHttp.pas)
  ⎿  Added 8 lines, removed 7 lines
      3279  
      3280  function TWinHttpWebSocket.StartReceiving(asyncContext: IAsyn
            cContext): Boolean;
      3281  var
      3282 -  received: DWORD;                                           
      3282 +  received  : DWORD;                                         
      3283    bufferType: TWinHttpWebSocketBufferType;
      3284 +  res       : DWORD;                                         
      3285  begin
      3286    Result := true;
      3287    if not (Receiving in asyncContext.WSStates) then begin
      3288      FLastError := Default(TWinHttpWebSocketError);
      3289      asyncContext.WSStates := asyncContext.WSStates + [Receivi
            ng];
      3289 -    Result := WinHttpWebSocketReceive(                       
      3290 -                FConnectionInfo.WebSocket,                   
      3291 -                FReceiveBuffer.Value, FReceiveBuffer.Size, re
           -ceived, bufferType) = 0;                                     
      3290 +    res := WinHttpWebSocketReceive(                          
      3291 +             FConnectionInfo.WebSocket,                      
      3292 +             FReceiveBuffer.Value, FReceiveBuffer.Size, recei
           +ved, bufferType);                                            
      3293 +    Result := res = 0;                                       
      3294      if not Result then begin
      3295        asyncContext.WSStates := asyncContext.WSStates - [Recei
            ving] + [Error];
      3294 -      var lastErr := Winapi.Windows.GetLastError;            
      3295 -      asyncContext.FailWS(WINHTTP_WEB_SOCKET_RECEIVE_OPERATIO
           -N, lastErr,                                                  
      3296 +      asyncContext.FailWS(WINHTTP_WEB_SOCKET_RECEIVE_OPERATIO
           +N, res,                                                      
      3297          Format('WinHttpWebSocketReceive failed with error %d.
             %s',
      3297 -          [lastErr, SysErrorMessage(lastErr)]));             
      3298 +          [res, SysErrorMessage(res)]));                     
      3299        Exit;
      3300      end;
      3301    end;

● Now let me also verify that HandleBufferReceived (Fix 2) doesn't have a
  reentrancy issue — it calls FailWS which calls HandleError (via
  OnWSRequestError), which sets FInsideHandler = true again. Let me check.

  Read 1 file (ctrl+o to expand)

● Let me check what FailWS's Done call does — it could trigger something
  unexpected when called from inside HandleBufferReceived.

  Searched for 1 pattern (ctrl+o to expand)

● Good, Done just sets a flag. Now there's one more concern —
  HandleBufferReceived is called from the async callback (inside MonitorEnter),
  and FailWS also calls Lock/Unlock. Let me check if this could deadlock.

  Read 1 file (ctrl+o to expand)

● The callback holds MonitorEnter(Self) (TAsyncContext), and FailWS calls
  Lock/Unlock which is also MonitorEnter(Self)/MonitorExit(Self) on
  TAsyncContext. Since Delphi monitors are reentrant (same thread can enter
  multiple times), this won't deadlock.

  But wait — HandleBufferReceived is called via FOnWSBufferReceived from
  AsyncCallback_WS_Read_Complete, which runs inside MonitorEnter(Self). Then
  HandleBufferReceived calls asyncContext.FailWS(...). The FailWS calls Lock
  (another MonitorEnter on the same TAsyncContext). Since it's the same thread,
  the reentrant monitor succeeds. Then FailWS calls Unlock (MonitorExit),
  decrementing the count. Fine.

  However, there's a subtle issue: HandleBufferReceived calls
  GetAsyncContext(asyncContext) which re-fetches the context. Let me verify this
   path more carefully.

  Read 1 file (ctrl+o to expand)

● Good. The callback calls FOnWSBufferReceived → HandleBufferReceived. In the
  close-frame case, HandleBufferReceived calls GetAsyncContext(asyncContext)
  then asyncContext.FailWS(...). The FailWS will call FOnWSRequestError →
  HandleError → FOnError (the application callback).

  The chain is: WinHTTP callback thread → MonitorEnter → Read_Complete →
  HandleBufferReceived → FailWS (reentrant lock, ok) → HandleError → FOnError
  (user callback).

  The concern is FInsideHandler. Let me trace it:
  1. HandleBufferReceived: FInsideHandler := true
  2. HandleError: FInsideHandler := true (already true, no-op)
  3. HandleError finally: FInsideHandler := false ← briefly wrong while still in
   HandleBufferReceived
  4. HandleBufferReceived Exit → finally: FInsideHandler := false

  Between steps 3 and 4, FInsideHandler is false for one instruction (Exit).
  This is the same thread so no other code can run. No issue.

  Another concern: HandleError resets FLastError at line 3013:
  FLastError := Default(TWinHttpWebSocketError);
  This would overwrite the FLastError set by GetCloseStatus() in
  HandleBufferReceived. But then HandleError immediately sets
  FLastError.Operation, .Error, and .ErrorMessage from the parameters we passed,
   which carry the close status info. So the final FLastError has the correct
  values.

  All changes look correct. Let me also verify Fix 4 (Shutdown) doesn't have the
   issue where ShuttingDown stays in WSStates on the error path.

  Read 1 file (ctrl+o to expand)

● There's a missing case: when res = 0 (synchronous success, not
  ERROR_IO_PENDING), execution falls through to line 3275 which properly clears
  ShuttingDown and sets ShutDown. That's correct.

  When res <> 0 and res <> ERROR_IO_PENDING (error), line 3269 removes
  ShuttingDown and adds Error. Good.

  When res = ERROR_IO_PENDING, we wait for ShuttingDown to be removed by the
  async callback (AsyncCallback_WS_Shutdown_Complete). Then line 3275 sets
  ShutDown. Let me verify that callback.

  Searched for 1 pattern (ctrl+o to expand)

● All checks pass. The callback removes ShuttingDown from WSStates, which breaks
   the while loop in Shutdown, and then line 3275 adds ShutDown. Correct.

  All four fixes are sound. Here's the final summary:

  1. StartReceiving — Now captures the actual error code returned by
  WinHttpWebSocketReceive (instead of the incorrect GetLastError call in the
  first version), sets the Error state, and calls FailWS to propagate through
  the OnError callback chain.
  2. HandleBufferReceived — Close frames with no data now call FailWS so the
  error propagates to the application via OnError.
  3. WinHttpWebSocketReceive wrapper — Always sets peBufferType on success, even
   when pdwBytesRead = 0 (e.g., close frames).
  4. Shutdown — Now detects and reports non-ERROR_IO_PENDING failures instead of
   always returning true.
  5. Header — Updated version to 3.19 with change description.

✻ Crunched for 2m 13s