Log before unregistering Fixes #9455

src/Build/BackEnd/Components/Logging/EventSourceSink.cs

@@ -537,15 +537,11 @@ private void RaiseProjectStartedEvent(object sender, ProjectStartedEventArgs bui
                     // if a logger has failed politely, abort immediately
                     // first unregister all loggers, since other loggers may receive remaining events in unexpected orderings
                     // if a fellow logger is throwing in an event handler.
-                    this.UnregisterAllEventHandlers();
+                    UnregisterAllEventHandlers();
                     throw;
                 }
                 catch (Exception exception)
                 {
-                    // first unregister all loggers, since other loggers may receive remaining events in unexpected orderings
-                    // if a fellow logger is throwing in an event handler.
-                    this.UnregisterAllEventHandlers();
-
                     if (ExceptionHandling.IsCriticalException(exception))
                     {
                         throw;
@@ -873,9 +869,9 @@ private void RaiseAnyEvent(object sender, BuildEventArgs buildEvent)
                     // if a logger has failed politely, abort immediately
                     // first unregister all loggers, since other loggers may receive remaining events in unexpected orderings
                     // if a fellow logger is throwing in an event handler.
-                    this.UnregisterAllEventHandlers();
+                    UnregisterAllEventHandlers();
 
-                    // We ought to dump this farther up the stack, but if for example a task is logging an event within a
+                    // We ought to dump this further up the stack, but if for example a task is logging an event within a
                     // catch(Exception) block and not rethrowing it, there's the possibility that this exception could
                     // just get silently eaten.  So better to have duplicates than to not log the problem at all. :)
                     ExceptionHandling.DumpExceptionToFile(exception);
@@ -884,11 +880,7 @@ private void RaiseAnyEvent(object sender, BuildEventArgs buildEvent)
                 }
                 catch (Exception exception)
                 {
-                    // first unregister all loggers, since other loggers may receive remaining events in unexpected orderings
-                    // if a fellow logger is throwing in an event handler.
-                    this.UnregisterAllEventHandlers();
-
-                    // We ought to dump this farther up the stack, but if for example a task is logging an event within a
+                    // We ought to dump this further up the stack, but if for example a task is logging an event within a
                     // catch(Exception) block and not rethrowing it, there's the possibility that this exception could
                     // just get silently eaten.  So better to have duplicates than to not log the problem at all. :)
                     ExceptionHandling.DumpExceptionToFile(exception);

src/Build/BackEnd/Components/RequestBuilder/RequestBuilder.cs

@@ -842,13 +842,25 @@ private async Task BuildAndReport()
                 {
                     // The build was likely cancelled. We do not need to log an error in this case.
                 }
-                else if (_projectLoggingContext is null)
+                else if (ex is InternalLoggerException)
                 {
-                    _nodeLoggingContext.LogError(BuildEventFileInfo.Empty, "UnhandledMSBuildError", ex.ToString());
+                    string realMessage = ex.Message;
+                    Exception realEx = ex;
+                    while (realEx.InnerException is not null)
+                    {
+                        realEx = realEx.InnerException;
+                        realMessage = realEx.Message;
+                    }
+
+                    (((LoggingContext)_projectLoggingContext) ?? _nodeLoggingContext).LogError(
+                        BuildEventFileInfo.Empty,
+                        "FatalErrorWhileLoggingWithInnerExceptionAndStack",
+                        realMessage,
+                        realEx.StackTrace);
                 }
                 else
                 {
-                    _projectLoggingContext.LogError(BuildEventFileInfo.Empty, "UnhandledMSBuildError", ex.ToString());
+                    (((LoggingContext)_projectLoggingContext) ?? _nodeLoggingContext).LogError(BuildEventFileInfo.Empty, "UnhandledMSBuildError", ex.ToString());
                 }
 
                 if (ExceptionHandling.IsCriticalException(ex))

src/Build/Resources/Strings.resx

@@ -469,6 +469,14 @@
     likely because of a programming error in the logger). When a logger dies, we cannot proceed with the build, and we throw a
     special exception to abort the build.</comment>
   </data>
+  <data name="FatalErrorWhileLoggingWithInnerExceptionAndStack" xml:space="preserve">
+    <value>MSB4017: The build stopped unexpectedly because of an unexpected logger failure.
+    {0}
+    {1}</value>
+    <comment>{StrBegin="MSB4017: "}UE: This message is used for a special exception that is thrown when a logger fails while logging an event (most
+    likely because of a programming error in the logger). When a logger dies, we cannot proceed with the build, and we throw a
+    special exception to abort the build.</comment>
+  </data>
   <data name="General.TwoVectorsMustHaveSameLength">
     <value>MSB3094: "{2}" refers to {0} item(s), and "{3}" refers to {1} item(s). They must have the same number of items.</value>
     <comment>{StrBegin="MSB3094: "}</comment>