From 1e5d6110c264af7c4a51927685e5d50637d9b9e9 Mon Sep 17 00:00:00 2001
From: Dmitry Vasilevsky <dmitryv@microsoft.com>
Date: Thu, 28 Jan 2021 13:25:19 -0800
Subject: [PATCH 1/3] Making stack trace printout optional

---
 src/Simulation/Common/SimulatorBase.cs             | 14 ++++++++------
 src/Simulation/Simulators.Tests/StackTraceTests.cs | 13 +++++++++++++
 2 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/src/Simulation/Common/SimulatorBase.cs b/src/Simulation/Common/SimulatorBase.cs
index 7d216c00edf..48b80a0e07c 100644
--- a/src/Simulation/Common/SimulatorBase.cs
+++ b/src/Simulation/Common/SimulatorBase.cs
@@ -43,6 +43,7 @@ public abstract class SimulatorBase : AbstractFactory<AbstractCallable>, IOperat
 
         public abstract string Name { get; }
 
+        public bool EnableStackTracePrinting { get; set; } = true;
 
         /// <summary>
         /// If the execution finishes in failure, this method returns the call-stack of the Q# operations 
@@ -125,12 +126,13 @@ public override AbstractCallable CreateInstance(Type t)
         protected void WriteStackTraceToLog(Exception exception, IEnumerable<StackFrame> callStack)
         {
             OnLog?.Invoke($"Unhandled exception. {exception.GetType().FullName}: {exception.Message}");
-            var first = true;
-            foreach (var sf in callStack)
-            {
-                var msg = (first ? " ---> " : "   at ") + sf.ToStringWithBestSourceLocation();
-                OnLog?.Invoke(msg);
-                first = false;
+            if (EnableStackTracePrinting) {
+                var first = true;
+                foreach (var sf in callStack) {
+                    var msg = (first ? " ---> " : "   at ") + sf.ToStringWithBestSourceLocation();
+                    OnLog?.Invoke(msg);
+                    first = false;
+                }
             }
             OnLog?.Invoke("");
         }
diff --git a/src/Simulation/Simulators.Tests/StackTraceTests.cs b/src/Simulation/Simulators.Tests/StackTraceTests.cs
index c3fead7b586..e429475cfb9 100644
--- a/src/Simulation/Simulators.Tests/StackTraceTests.cs
+++ b/src/Simulation/Simulators.Tests/StackTraceTests.cs
@@ -381,6 +381,19 @@ public void ErrorLogTest()
                 Assert.StartsWith("   at Microsoft.Quantum.Simulation.Simulators.Tests.Circuits.AlwaysFail4 on", logs[5]);
                 Assert.Equal("", logs[6]);
             }
+
+            logs.Clear();
+            sim.EnableStackTracePrinting = false;
+            try
+            {
+                QVoid res = sim.Execute<AlwaysFail4, QVoid, QVoid>(QVoid.Instance);
+            }
+            catch (ExecutionFailException)
+            {
+                Assert.Equal(2, logs.Count);
+                Assert.StartsWith("Unhandled exception. Microsoft.Quantum.Simulation.Core.ExecutionFailException: Always fail", logs[0]);
+                Assert.Equal("", logs[1]);
+            }
         }
     }
 }
\ No newline at end of file

From c1b60fe7dbce1528b2b389e8e53e8407f7e610a2 Mon Sep 17 00:00:00 2001
From: Dmitry Vasilevsky <dmitryv@microsoft.com>
Date: Thu, 28 Jan 2021 13:31:34 -0800
Subject: [PATCH 2/3] Adjusted brace indentation

---
 src/Simulation/Common/SimulatorBase.cs | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/Simulation/Common/SimulatorBase.cs b/src/Simulation/Common/SimulatorBase.cs
index 48b80a0e07c..21b4097e5c5 100644
--- a/src/Simulation/Common/SimulatorBase.cs
+++ b/src/Simulation/Common/SimulatorBase.cs
@@ -126,9 +126,11 @@ public override AbstractCallable CreateInstance(Type t)
         protected void WriteStackTraceToLog(Exception exception, IEnumerable<StackFrame> callStack)
         {
             OnLog?.Invoke($"Unhandled exception. {exception.GetType().FullName}: {exception.Message}");
-            if (EnableStackTracePrinting) {
+            if (EnableStackTracePrinting)
+            {
                 var first = true;
-                foreach (var sf in callStack) {
+                foreach (var sf in callStack)
+                {
                     var msg = (first ? " ---> " : "   at ") + sf.ToStringWithBestSourceLocation();
                     OnLog?.Invoke(msg);
                     first = false;

From 09c92c74a4d72e3ad7d5da97cd1c1e4069ee3d5e Mon Sep 17 00:00:00 2001
From: Dmitry Vasilevsky <dmitryv@microsoft.com>
Date: Thu, 28 Jan 2021 18:00:16 -0800
Subject: [PATCH 3/3] Added comment

---
 src/Simulation/Common/SimulatorBase.cs | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/Simulation/Common/SimulatorBase.cs b/src/Simulation/Common/SimulatorBase.cs
index 21b4097e5c5..f91ef88d78a 100644
--- a/src/Simulation/Common/SimulatorBase.cs
+++ b/src/Simulation/Common/SimulatorBase.cs
@@ -43,6 +43,11 @@ public abstract class SimulatorBase : AbstractFactory<AbstractCallable>, IOperat
 
         public abstract string Name { get; }
 
+        /// <summary>
+        /// When exception printing is enabled, the value of this property controls stack trace printout.
+        /// When set to <c>true</c> (default), the stack trace is printed in addition to the exception message."
+        /// When set to <c>false</c>, the exception message is printed without the stack trace."
+        /// </summary>
         public bool EnableStackTracePrinting { get; set; } = true;
 
         /// <summary>