Fix breakpoint setting deadlock (#1112)

* Fix breakpoint setting deadlock

* codacy issues

Author: TylerLeonhardt

src/PowerShellEditorServices/Services/DebugAdapter/DebugEventHandlerService.cs

@@ -128,7 +128,7 @@ private void DebugService_BreakpointUpdated(object sender, BreakpointUpdatedEven
         {
             string reason = "changed";
 
-            if (_debugStateService.SetBreakpointInProgress)
+            if (_debugStateService.IsSetBreakpointInProgress)
             {
                 // Don't send breakpoint update notifications when setting
                 // breakpoints on behalf of the client.

src/PowerShellEditorServices/Services/DebugAdapter/DebugStateService.cs

@@ -3,10 +3,16 @@
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 //
 
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.PowerShell.EditorServices.Utility;
+
 namespace Microsoft.PowerShell.EditorServices.Services
 {
     internal class DebugStateService
     {
+        private readonly SemaphoreSlim _setBreakpointInProgressHandle = AsyncUtils.CreateSimpleLockingSemaphore();
+
         internal bool NoDebug { get; set; }
 
         internal string Arguments { get; set; }
@@ -25,8 +31,20 @@ internal class DebugStateService
 
         internal bool IsInteractiveDebugSession { get; set; }
 
-        internal bool SetBreakpointInProgress { get; set; }
+        // If the CurrentCount is equal to zero, then we have some thread using the handle.
+        internal bool IsSetBreakpointInProgress => _setBreakpointInProgressHandle.CurrentCount == 0;
 
         internal bool IsUsingTempIntegratedConsole { get; set; }
+
+        internal void ReleaseSetBreakpointHandle()
+        {
+            _setBreakpointInProgressHandle.Release();
+        }
+
+        internal async Task WaitForSetBreakpointHandleAsync()
+        {
+            await _setBreakpointInProgressHandle.WaitAsync()
+                .ConfigureAwait(continueOnCapturedContext: false);
+        }
     }
 }

src/PowerShellEditorServices/Services/DebugAdapter/Handlers/BreakpointHandlers.cs

@@ -48,7 +48,7 @@ public async Task<SetFunctionBreakpointsResponse> Handle(SetFunctionBreakpointsA
             CommandBreakpointDetails[] updatedBreakpointDetails = breakpointDetails;
             if (!_debugStateService.NoDebug)
             {
-                _debugStateService.SetBreakpointInProgress = true;
+                await _debugStateService.WaitForSetBreakpointHandleAsync();
 
                 try
                 {
@@ -63,7 +63,7 @@ await _debugService.SetCommandBreakpointsAsync(
                 }
                 finally
                 {
-                    _debugStateService.SetBreakpointInProgress = false;
+                    _debugStateService.ReleaseSetBreakpointHandle();
                 }
             }
 
@@ -196,7 +196,7 @@ public async Task<SetBreakpointsResponse> Handle(SetBreakpointsArguments request
             BreakpointDetails[] updatedBreakpointDetails = breakpointDetails;
             if (!_debugStateService.NoDebug)
             {
-                _debugStateService.SetBreakpointInProgress = true;
+                await _debugStateService.WaitForSetBreakpointHandleAsync();
 
                 try
                 {
@@ -212,7 +212,7 @@ await _debugService.SetLineBreakpointsAsync(
                 }
                 finally
                 {
-                    _debugStateService.SetBreakpointInProgress = false;
+                    _debugStateService.ReleaseSetBreakpointHandle();
                 }
             }