Testing if variable is empty changed?!

[AIstarter]

Hello,

I recently upgraded from 3.3.8.1 to 3.3.14.2 and noticed something that doesn't make sense to me:

I'm using a script to fetch records from an MSSQL Database. Some fields are empty (which is correct) and using 3.3.8.1 this works fine and sets $var2 to "something"

If ($var = "") Then
    $var2 = "something"
EndIf

After upgrading to 3.3.14.2 this doesn't work anymore. The String has a length of zero (which is the way I use now as a workaround)

If (StringLen($var) = 0) Then
    $var2 = "something"
EndIf

But I don't understand why this won't work anymore. Any Idea?

Thanks!

[TheDcoder]

Both work for me:

Local $var = ""

If (StringLen($var) = 0) Then
    MsgBox(0, 1, "Works")
EndIf

If ($var = "") Then
    MsgBox(0, 2, "Works")
EndIf

I think something is wrong in your code... did you check for script breaking changes?

[AIstarter]

Yes I did. I didn't notice anyhting regarding my problem.

But declaring the var with "" as in your example should work in any case - since then it is indeed '""'. Even with a new script and just declaring Dim $var (without = "") works.

In my case it's part of an array that comes back from am MSSQL query. This returns NULL - and it seems that this was handled in a different way? I tested my code on an old 3.3.8.1 installation and the same code (without StringLen) works perfectly. Strange?!

[TheDcoder]

Try using:

String($var)

Before the if statement

[AIstarter]

Indeed

$var = String($var)

works fine with = ""

Did I miss something in the changelog? Or was is just a guess? Anyway, thanks a lot - I'll do a bit of code-rework now back to = "" with the String statement

[TheDcoder]

My pleasure!

[mLipok]

Null.....

You get null from SQL. 

Edited January 25, 2016 by mLipok

[AIstarter]

35 minutes ago, mLipok said:

Null.....

You get null from SQL. 

Yes, I get null from SQL - that didn't change between AutoIT Versions and is still the same. But testing for null did change as it seems. In 3.3.8.1. a test for null works fine with just = "" - apparently this changed in new versions where you have to take a look at StringLen or String($var). That was my problem...

[mLipok]

16 minutes ago, AIstarter said:

But testing for null did change as it seems. In 3.3.8.1. a test for null works fine with just = "" - apparently this changed in new versions where you have to take a look at StringLen or String($var). That was my problem...

 

https://www.autoitscript.com/autoit3/docs/autoit_changelog.txt
3.3.10.0 (23rd December, 2013) (Release)
Added: Keyword Null.
 

You should check like this:
 

If $var = Null or $var = "" then
...
EndIf

 

[AIstarter]

Thanks @mLipok - i did read the changelog but didn't quite register what keyword meant. Checking for Null works of course.