Preferred Error Handling

[hecon5]

I've noticed DebugMode and LogUnhandledErrors are now in their own module, which is good I think. I also noticed that newer functions seem to use LogUnhandledErrors instead of DebugMode, is LogUnhandledErrors the new preferred mechanism for handling Errors? From reading how DebugMode seems to work, it simply points to LogUnhandledErrors, but thought I'd check and see if I'm missing something.

[joyfullservice]

Great question! Yes, your observation is correct. My original approach was to use the DebugMode function as part of an inline error handling switch. It was concise and effective, but had one main problem. DebugMode reads and acts like a property, but it also contained an important side effect that was not readily apparent on the surface.

Because an On Error directive silently discards any existing error condition, otherwise untrapped errors would be lost in the process. By using this function as part of my conditional On Error directive, I was able to effectively log or break on these errors. I suppose I could have been more descriptive with the function name, but I wasn't excited about GetDebugModeAfterCheckingForUnhandledErrors.... 😉 It also doesn't do so great with the single responsibility principle. I later added a required parameter to give a bit of a clue about something else taking place, but I still wasn't thrilled with it.

While I knew what DebugMode meant, it was understandably confusing for new developers on the project. I am sure they were puzzling over the sanity of the following line:

If DebugMode(True) Then On Error Resume Next Else On Error Resume Next`

After a lot of thought and consideration, I finally settled on making this two lines with hopefully a greater level of clarity on what is actually taking place. Less clever and more clear.

' Old way to set On Error Resume Next
If DebugMode(True) Then On Error Resume Next Else On Error Resume Next

' New (preferred) way
LogUnhandledErrors
On Error Resume Next

' Enabling inline debugging remains the same
If DebugMode(True) Then On Error GoTo 0 Else On Error Resume Next

Inline debugging is mainly intended for debugging functionality in the add-in where it is useful to jump right to the line causing the error. As we understand more about the specific errors being thrown, we can use the Catch functions to appropriately deal with the specific errors.