feature #2872 Add spaceless filter (fabpot)

This PR was squashed before being merged into the 1.x branch (closes #2872).

Discussion
----------

Add spaceless filter

Commits
-------

a22a5c4b fixed CS
743767bc re-implemented the spaceless tag to reuse the filter tag logic
b823898e added a spaceless filter
1ba79416 removed unneeded usage of spaceless in tests

CHANGELOG

@@ -1,5 +1,6 @@
 * 1.38.0 (2019-XX-XX)
 
+ * added a spaceless filter
  * added max value to the "random" function
  * made namespace classes the default classes (PSR-0 ones are aliases now)
  * removed duplicated directory separator in FilesystemLoader

doc/filters/spaceless.rst

@@ -0,0 +1,54 @@
+``spaceless``
+=============
+
+.. versionadded:: 1.38
+
+    The ``spaceless`` filter was added in Twig 1.38.
+
+Use the ``spaceless`` filter to remove whitespace *between HTML tags*, not
+whitespace within HTML tags or whitespace in plain text:
+
+.. code-block:: jinja
+
+    {{
+        "<div>
+            <strong>foo</strong>
+        </div>
+        "|spaceless }}
+
+    {# output will be <div><strong>foo</strong></div> #}
+
+You can combine ``spaceless`` with the ``filter`` tag to apply the
+transformation on large amounts of HTML:
+
+.. code-block:: jinja
+
+    {% filter spaceless %}
+        <div>
+            <strong>foo</strong>
+        </div>
+    {% endfilter %}
+
+    {# output will be <div><strong>foo</strong></div> #}
+
+This tag is not meant to "optimize" the size of the generated HTML content but
+merely to avoid extra whitespace between HTML tags to avoid browser rendering
+quirks under some circumstances.
+
+.. tip::
+
+    If you want to optimize the size of the generated HTML content, gzip
+    compress the output instead.
+
+.. tip::
+
+    If you want to create a tag that actually removes all extra whitespace in
+    an HTML string, be warned that this is not as easy as it seems to be
+    (think of ``textarea`` or ``pre`` tags for instance). Using a third-party
+    library like Tidy is probably a better idea.
+
+.. tip::
+
+    For more information on whitespace control, read the
+    :ref:`dedicated section <templates-whitespace-control>` of the documentation and learn how
+    you can also use the whitespace control modifier on your tags.

doc/tags/spaceless.rst

@@ -1,6 +1,10 @@
 ``spaceless``
 =============
 
+.. tip::
+
+    As of Twig 1.38, use the :doc:`spaceless <../filters/spaceless>` filter instead.
+
 Use the ``spaceless`` tag to remove whitespace *between HTML tags*, not
 whitespace within HTML tags or whitespace in plain text:
 

src/Extension/CoreExtension.php

@@ -184,6 +184,7 @@ class CoreExtension extends AbstractExtension
             new TwigFilter('striptags', 'strip_tags'),
             new TwigFilter('trim', 'twig_trim_filter'),
             new TwigFilter('nl2br', 'nl2br', ['pre_escape' => 'html', 'is_safe' => ['html']]),
+            new TwigFilter('spaceless', 'twig_spaceless', ['is_safe' => ['html']]),
 
             // array helpers
             new TwigFilter('join', 'twig_join_filter'),
@@ -357,6 +358,7 @@ function twig_random(Environment $env, $values = null, $max = null)
             $min = $values;
             $max = $max;
         }
+
         return mt_rand($min, $max);
     }
 
@@ -988,6 +990,16 @@ function twig_trim_filter($string, $characterMask = null, $side = 'both')
     }
 }
 
+/**
+ * Removes whitespaces between HTML tags.
+ *
+ * @return string
+ */
+function twig_spaceless($content)
+{
+    return preg_replace('/>\s+</', '><', $content);
+}
+
 /**
  * Escapes a string.
  *

src/Node/SpacelessNode.php

@@ -18,6 +18,8 @@ use Twig\Compiler;
  *
  * It removes spaces between HTML tags.
  *
+ * @internal Not used anymore, to be removed in 3.0
+ *
  * @author Fabien Potencier <fabien@symfony.com>
  */
 class SpacelessNode extends Node

src/TokenParser/SpacelessTokenParser.php

@@ -11,7 +11,10 @@
 
 namespace Twig\TokenParser;
 
-use Twig\Node\SpacelessNode;
+use Twig\Node\BlockNode;
+use Twig\Node\Expression\BlockReferenceExpression;
+use Twig\Node\Expression\ConstantExpression;
+use Twig\Node\PrintNode;
 use Twig\Token;
 
 /**
@@ -30,13 +33,23 @@ class SpacelessTokenParser extends AbstractTokenParser
 {
     public function parse(Token $token)
     {
-        $lineno = $token->getLine();
+        $this->parser->getStream()->injectTokens([
+            new Token(Token::NAME_TYPE, 'spaceless', $token->getLine()),
+        ]);
 
+        $name = $this->parser->getVarName();
+        $ref = new BlockReferenceExpression(new ConstantExpression($name, $token->getLine()), null, $token->getLine(), $this->getTag());
+
+        $filter = $this->parser->getExpressionParser()->parseFilterExpressionRaw($ref, $this->getTag());
         $this->parser->getStream()->expect(Token::BLOCK_END_TYPE);
+
         $body = $this->parser->subparse([$this, 'decideSpacelessEnd'], true);
         $this->parser->getStream()->expect(Token::BLOCK_END_TYPE);
 
-        return new SpacelessNode($body, $lineno, $this->getTag());
+        $block = new BlockNode($name, $body, $token->getLine());
+        $this->parser->setBlock($name, $block);
+
+        return new PrintNode($filter, $token->getLine(), $this->getTag());
     }
 
     public function decideSpacelessEnd(Token $token)

test/Twig/Tests/Fixtures/filters/spaceless.test

@@ -0,0 +1,8 @@
+--TEST--
+"spaceless" filter
+--TEMPLATE--
+{{ "    <div>   <div>   foo   </div>   </div>"|spaceless }}
+--DATA--
+return []
+--EXPECT--
+<div><div>   foo   </div></div>

test/Twig/Tests/Fixtures/tags/inheritance/block_expr.test

@@ -8,7 +8,6 @@ block_expr
     {{- parent() -}}
 {% endblock %}
 --TEMPLATE(base.twig)--
-{% spaceless %}
 {% block element -%}
     <div>
         {%- if item.children is defined %}
@@ -18,7 +17,6 @@ block_expr
         {%- endif -%}
     </div>
 {%- endblock %}
-{% endspaceless %}
 --DATA--
 return [
     'item' => [

test/Twig/Tests/Fixtures/tags/inheritance/block_expr2.test

@@ -10,7 +10,6 @@ block_expr2
 --TEMPLATE(base2.twig)--
 {% extends "base.twig" %}
 --TEMPLATE(base.twig)--
-{% spaceless %}
 {% block element -%}
     <div>
         {%- if item.children is defined %}
@@ -20,7 +19,6 @@ block_expr2
         {%- endif -%}
     </div>
 {%- endblock %}
-{% endspaceless %}
 --DATA--
 return [
     'item' => [