LastError and LastErrorDetail in FileMaker

[MonkeybreadSoftware]

We used to suggest scripts like the one below to install the MBS FileMaker Plugin and check for the error status. But the following script has a big problem, a little oversight on how FileMaker works. Try to guess what is wrong here:

Install Plug-In File [ Install Plugin Update if needed::Plugin File Mac ]
Set Variable [ $LastError ; Value: Get(LastError) ]
Set Variable [ $LastErrorDetail ; Value: Get(LastErrorDetail) ]

The script installs the plugin and in case of an error, we like to query the error code and message. But this script never gets the last error detail! You may guess that we query the last error number and detail for the first line with the installation. But what we do is to query the detail for LastErrorDetail, we get the result from the Set Variable script line in the second line. Yes, the Set Variable will clear the error state and thus we never get the detail for the first line.

We have a fixed script:

Install Plug-In File [ Install Plugin Update if needed::Plugin File Mac ]
Set Variable [ $r ; Value: Let([
   $lastError = Get(LastError);
   $lastErrorMessage = Get(LastErrorDetail)
]; 1) ]

This time we use a Let() statement to query both LastError and LastErrorDetail and assign it to variables. This way the Set Variable can overwrite the error state after we got the values.

If you have existing scripts using Get(LastErrorDetail), you may want to update them to use a Let statement.

[tonywhitelive]

Very good advice...

The explanation in...

Get(LastError)

Returns a number for the error that occurred in the execution of the most recently executed script step.

...also applies to Get(LastErrorDetail), and probably applies to Get(LastErrorLocation).

We use a Custom Function that contains Get(LastError), Get(LastErrorDetail), Get(LastErrorLocation), and more...into which we pass a script_comment.

The output of this Custom Function is referenced in the Script and also passed into our HelpRequest File.

We talked for a few minutes about this at the most recent DIGFM meeting

DIGFM: Roadmap Warrior — Don't get MAD to the MAX. Get even with the problem.

DIGFM: Roadmap Warrior — Don't get MAD to the MAX. Get even with the problem.

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The Custom Function that we use for the...

Set Error Logging

... is here...

@customDebugInfo ( script_comment )

FileMaker Custom Function: @customDebugInfo ( script_comment )

// the basic idea for these Custom Functions is to capture and log information that is useful in tracking down errors.

Side note: We often use @ as a prefix for Custom Functions in part because it makes Custom Functions more visible in a Script when using the MBS (MonkeybreadSoftware) Search feature.