composer.json

{
    "name": "knksmith57/lnc-identity-call-stack-error",
    "description": "example setup for reproducing LnC #235",
    "authors": [
        {
            "name": "Kyle Smith",
            "email": "[email protected]"
        }
    ],
    "require": {
        "zordius/lightncandy": "v0.89"
    }
}

composer.lock

{
    "_readme": [
        "This file locks the dependencies of your project to a known state",
        "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#composer-lock-the-lock-file",
        "This file is @generated automatically"
    ],
    "hash": "920b6a4b9ea52bba83e42ff4d2a07739",
    "content-hash": "3d8a57e817766d5aa06e8486b084d658",
    "packages": [
        {
            "name": "zordius/lightncandy",
            "version": "v0.89",
            "source": {
                "type": "git",
                "url": "https://github.com/zordius/lightncandy.git",
                "reference": "af1f9adec7bc684409cd2b01cbca02967edc14b4"
            },
            "dist": {
                "type": "zip",
                "url": "https://api.github.com/repos/zordius/lightncandy/zipball/af1f9adec7bc684409cd2b01cbca02967edc14b4",
                "reference": "af1f9adec7bc684409cd2b01cbca02967edc14b4",
                "shasum": ""
            },
            "require": {
                "php": ">=5.3.0"
            },
            "require-dev": {
                "phpunit/phpunit": "4.0.17"
            },
            "type": "library",
            "autoload": {
                "psr-4": {
                    "LightnCandy\\": "src"
                }
            },
            "notification-url": "https://packagist.org/downloads/",
            "license": [
                "MIT"
            ],
            "authors": [
                {
                    "name": "Zordius Chen",
                    "email": "[email protected]"
                }
            ],
            "description": "An extremely fast PHP implementation of handlebars ( http://handlebarsjs.com/ ) and mustache ( http://mustache.github.io/ ).",
            "homepage": "https://github.com/zordius/lightncandy",
            "keywords": [
                "handlebars",
                "logicless",
                "mustache",
                "php",
                "template"
            ],
            "time": "2015-12-05 13:08:25"
        }
    ],
    "packages-dev": [],
    "aliases": [],
    "minimum-stability": "stable",
    "stability-flags": [],
    "prefer-stable": false,
    "prefer-lowest": false,
    "platform": [],
    "platform-dev": []
}

main.php

#!/usr/bin/env php
<?php
error_reporting(E_ALL);
require_once('vendor/autoload.php');

use LightnCandy\LightnCandy;

$template = '{{#> "myPartial"}}{{>(identity @root.foo)}}{{/"myPartial"}}';
$myPartial = "<div>{{> @partial-block}}</div>";

$phpStr = LightnCandy::compile($template, [
  'flags' => 0
    | LightnCandy::FLAG_BESTPERFORMANCE
    | LightnCandy::FLAG_ERROR_EXCEPTION
    | LightnCandy::FLAG_RUNTIMEPARTIAL
    | LightnCandy::FLAG_SPACECTL
    | LightnCandy::FLAG_SPVARS
    | LightnCandy::FLAG_HANDLEBARS,
  'helpers' => [
    'identity' => '\HandlebarsHelpers::identity'
  ],
  'partials' => [
    'myPartial' => $myPartial
  ]
]);

$output = eval('?>' . $phpStr);

echo $output([
  'foo' => 'myPartial'
]);

class HandlebarsHelpers
{
  public static function identity ($args) {
    $argc = count($args);
    if ($argc !== 1) {
      throw new \RuntimeException('identity helper requires exactly one positional argument');
    }

    return $args[0];
  }
}

Hello, I just found you use @partial-block inside a partial block, that's a recursive and handlebars.js can not work, neither. I created a handlebars.js example here: https://jsfiddle.net/0ncmugm7/ , you will see Uncaught RangeError: Maximum call stack size exceeded if you check the javascript console output.