Does EE3 support preload-replace with conditionals in grid fields?

Question

I keep running into issues using preload-replace with conditionals that are in a grid field.

I have the preload: {preload_replace:staticchannelslug="gp"}

And am trying to use it like so:

        {page_header_{staticchannelslug}}
            
            <h1>{if page_header_{staticchannelslug}:alt_title}...{if:else}...{/if}</h1>
            
        {/page_header_{staticchannelslug}}

This throws the error:

Something has gone wrong and this URL cannot be processed at this time.

EDIT:

Error with debug on:

You have an invalid conditional in your template. Please review your conditionals for an unclosed string, invalid operators, a missing }, or a missing {/if}.

Parser State: Unexpected ‘alt_title’ (VARIABLE); expected RD in Template “pages/general-page” on line 9.

//end edit

If I don't use the preload and change it to this, I get no errors:

        {page_header_gp}
            
            <h1>{if page_header_gp:alt_title}...{if:else}...{/if}</h1>
            
        {/page_header_gp}

I've used this same kind of method for years in EE2, but just running into issues with it in EE3 :/

This doesn't work either, same error message:

        {if '{page_header_{staticchannelslug}'}

            {page_header_{staticchannelslug}}
                            ...
            {/page_header_{staticchannelslug}}

        {/if}

Any ideas on what the issue is here or what I may be missing?

Thanks.

Answer 1

This is an instance were you will need to quote your conditional, since it's not a true variable. Starting in version 2.9.0, the conditionals parser learned how to behave, and parses conditionals as soon as they are ready. Since what you have in the first example doesn't look like a valid variable, it doesn't know to wait for a value before evaluating it. In other words, since your variable is actually a string that you are putting together with other variables, you need to use:

{if '{page_header_{staticchannelslug}'}

That should be working for you, though you indicate it is not, and is working in my tests.

{preload_replace:replaced_var="image"}

....

{exp:channel:entries channel="blog"}
    {if "{blog_{replaced_var}:image}"}
        There's an image!
    {if:else}
        No image!
    {/if}
{/exp:channel:entries}

If you are still getting the error after following this pattern, reduce your template further to ensure you don't have a similar conditional somewhere else, in an embed, etc.