ATTN all: New customfield checkbox behaviour, review your code! EQ 'yes' and NE 'yes'

[AHerb]

In 9.07 custom fields checkboxes were changed from 'yes' to '1' since it should be considered a boolean field.

At the moment all existing (pre 9.07) customfield checkboxes are returning 'yes' until you cahnge their state. After they are re-activated they will return 1. You may have a mixture of 'yes' and 1 for the same product.
details

    <mvt:if expr="g.my_customfield_checkbox_var EQ 'yes'">    <---- WRONG
    <mvt:if expr="g.my_customfield_checkbox_var NE 'yes'">    <---- WRONG
    <mvt:if expr="NOT ISNULL g.my_customfield_checkbox_var">    <---- CORRECT matches yes and 1
    <mvt:if expr="ISNULL g.my_customfield_checkbox_var">    <---- CORRECT matches an empty field or not assigned variable

Review your code guys or it may stop working as expected one day.

[Kent Multer]

I don't think (ISNULL g.xxx) will return 1 if g.xxx contains the empty string. ISNULL only returns 1 if the variable has never been assigned any value. Empty-string is not the same as null. If you set g.xxx to 'something' and then set it to empty-string, it still has a value, and (ISNULL g.xxx) will return false.

[dcarver]

ISNULL will return 1 if the variable is a string and the string length is 0.

[Kent Multer]

Are you positive? I had a problem with a module a while ago, and that turned out to be the cause IIRC.

[dcarver]

Are you positive? I had a problem with a module a while ago, and that turned out to be the cause IIRC.

I just ran tests to verify it.

<mvt:eval expr="ISNULL g.Test" /><br />

<mvt:assign name="g.Test" value="'123'" />
<mvt:eval expr="ISNULL g.Test" /><br />

<mvt:assign name="g.Test" value="''" />
<mvt:eval expr="ISNULL g.Test" /><br />

gave me this output

1
0
1

[Kent Multer]

That seems pretty definitive. I'm pretty sure I saw the opposite behavior in my own work. I was writing Miva Script at the time, not template code.

Thanks --

[Bruce - PhosphorMedia]

I was under the impression that, depending on the data type of the field, and empty field could still give a positive on 'ISNULL' if the field was not specifically set to be 'null' with no value. For example, a text type field could contain a 'space', which ISNULL would eval to 'true'.

[AHerb]

But space is not an empty field. Space has a char id.
My only concern is '0', as Miva guys want to treat checkbox as a boolean field they may decide to return 0 when checkbox is not checked. ISNULL will fail in this case

        <mvt:eval expr="ISNULL g.tst" />
        <mvt:assign name="g.tst" value="0" />
        <mvt:eval expr="ISNULL g.tst" />
        <mvt:assign name="g.tst" value="1" />
        <mvt:eval expr="ISNULL g.tst" />
        <mvt:assign name="g.tst" value="'yes'" />
        <mvt:eval expr="ISNULL g.tst" />
        <mvt:assign name="g.tst" value="''" />
        <mvt:eval expr="ISNULL g.tst" />


1 0 0 0 1

[Bruce - PhosphorMedia]

oh, sorry herb, i was replying to kent's comment.