Unable to resolve partial when using sub expression and partial resolver

[eliashaeussler]

Hi!

I get an exception when using sub expressions (lookup) within a partial call in combination with a configured partialResolver. Let me sum up things a little bit.

Failing example: Dynamic lookup with configured partial resolver

Given the following template (template-1.hbs):

{{> (lookup . 'partialName')}}

And the following partial (partial.hbs):

Hello from the partial!

And this is my PHP code (test-1.php):

$template = \DevTheorem\Handlebars\Handlebars::compile(
    file_get_contents(__DIR__ . '/template-1.hbs'),
    new \DevTheorem\Handlebars\Options(
        partialResolver: static function (\DevTheorem\Handlebars\Context $context, string $name) {
            return file_get_contents(__DIR__ . '/' . $name . '.hbs');
        },
    ),
);

echo $template([
    'partialName' => 'partial',
]);

I receive the following exception:

$ php test-1.php
PHP Fatal error:  Uncaught Exception: Runtime: the partial partial could not be found in /xxx/vendor/devtheorem/php-handlebars/src/Runtime.php:293
Stack trace:
#0 /xxx/vendor/devtheorem/php-handlebars/src/Handlebars.php(41) : eval()'d code(16): DevTheorem\Handlebars\Runtime::p(Object(DevTheorem\Handlebars\RuntimeContext), 'partial', Array, 0, '')
#1 /xxx/test-1.php(14): DevTheorem\Handlebars\Handlebars::{closure}(Array)
#2 {main}
  thrown in /xxx/vendor/devtheorem/php-handlebars/src/Runtime.php on line 293

Fatal error: Uncaught Exception: Runtime: the partial partial could not be found in /xxx/vendor/devtheorem/php-handlebars/src/Runtime.php:293
Stack trace:
#0 /xxx/vendor/devtheorem/php-handlebars/src/Handlebars.php(41) : eval()'d code(16): DevTheorem\Handlebars\Runtime::p(Object(DevTheorem\Handlebars\RuntimeContext), 'partial', Array, 0, '')
#1 /xxx/test-1.php(14): DevTheorem\Handlebars\Handlebars::{closure}(Array)
#2 {main}
  thrown in /xxx/vendor/devtheorem/php-handlebars/src/Runtime.php on line 293

Working example 2: Dynamic lookup without (!) partial resolver

Same template like example 1, but a different PHP code:

$template = \DevTheorem\Handlebars\Handlebars::compile(
    file_get_contents(__DIR__ . '/template-2.hbs'),
    new \DevTheorem\Handlebars\Options(
        partials: [
            'partial' => file_get_contents(__DIR__ . '/partial.hbs'),
        ],
    ),
);

echo $template([
    'partialName' => 'partial',
]);

This works as expected:

$ php test-2.php
Hello from the partial!

Working example 3: Fixed partial name with configured partial resolver

Template:

{{> partial}}

PHP code:

$template = \DevTheorem\Handlebars\Handlebars::compile(
    file_get_contents(__DIR__ . '/template-3.hbs'),
    new \DevTheorem\Handlebars\Options(
        partialResolver: static function (\DevTheorem\Handlebars\Context $context, string $name) {
            return file_get_contents(__DIR__ . '/' . $name . '.hbs');
        },
    ),
);

echo $template();

This works as expected:

$ php test-3.php
Hello from the partial!

Working example 4: Fixed partial without (!) partial resolver

Same template like example 3, but a different PHP code:

$template = \DevTheorem\Handlebars\Handlebars::compile(
    file_get_contents(__DIR__ . '/template-4.hbs'),
    new \DevTheorem\Handlebars\Options(
        partials: [
            'partial' => file_get_contents(__DIR__ . '/partial.hbs'),
        ],
    ),
);

echo $template();

This works as expected:

$ php test-4.php
Hello from the partial!

[theodorejb]

Currently a partial resolver is only executed when resolving partials at compile time (the same as with a helper resolver). For the failing example to work, the specified partialResolver function would have to be compiled into the template code and executed at runtime. I'm not sure if that's actually desirable.

[eliashaeussler]

Thanks for your answer, which sounds very logic to me. Would it be possible to include the partial resolver in the compiled template if it's defined as first-class callable syntax instead of an anonymous function? Something like this:

$template = \DevTheorem\Handlebars\Handlebars::compile(
    file_get_contents(__DIR__ . '/template-1.hbs'),
    new \DevTheorem\Handlebars\Options(
        partialResolver: MyPartialResolver::resolve(...),
    ),
);

echo $template([
    'partialName' => 'partial',
]);