From 8d18437db014e6ba931bcb6fcdbde75e4905beed Mon Sep 17 00:00:00 2001
From: blmage <bl.mage.fr@gmail.com>
Date: Fri, 14 May 2021 12:31:05 +0200
Subject: [PATCH 01/12] Fix PHP code in template minifier test

The template minifier should not fix PHP code and hide errors from the user
---
 .../Framework/View/Test/Unit/Template/Html/MinifierTest.php   | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/internal/Magento/Framework/View/Test/Unit/Template/Html/MinifierTest.php b/lib/internal/Magento/Framework/View/Test/Unit/Template/Html/MinifierTest.php
index 01b274eb529b5..87ac7b484c182 100644
--- a/lib/internal/Magento/Framework/View/Test/Unit/Template/Html/MinifierTest.php
+++ b/lib/internal/Magento/Framework/View/Test/Unit/Template/Html/MinifierTest.php
@@ -150,8 +150,8 @@ public function testMinify(): void
             var i = 1;// comment
             var j = 1;// <?php echo 'hi' ?>
 //<?php ?> ')){
-// if (<?php echo __('hi')) { ?>
-// if (<?php )) {
+// if (<?php echo __('hi') ?>) {
+// if (<?php {}; ?>)) {
 // comment
             //<![CDATA[
             var someVar = 123;

From 7102e875ec0218ba61564575d6e1b26b13daa884 Mon Sep 17 00:00:00 2001
From: blmage <bl.mage.fr@gmail.com>
Date: Fri, 14 May 2021 12:41:43 +0200
Subject: [PATCH 02/12] Improve detection of heredocs in minified templates

---
 lib/internal/Magento/Framework/View/Template/Html/Minifier.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/internal/Magento/Framework/View/Template/Html/Minifier.php b/lib/internal/Magento/Framework/View/Template/Html/Minifier.php
index 3eb8baec7f569..ac849804dbfe6 100644
--- a/lib/internal/Magento/Framework/View/Template/Html/Minifier.php
+++ b/lib/internal/Magento/Framework/View/Template/Html/Minifier.php
@@ -119,7 +119,7 @@ public function minify($file)
         //Storing Heredocs
         $heredocs = [];
         $content = preg_replace_callback(
-            '/<<<([A-z]+).*?\1;/ims',
+            '/<<<([A-z]+).*?\1\s*;/ims',
             function ($match) use (&$heredocs) {
                 $heredocs[] = $match[0];
 

From e3a6ef780744120251abeb89d94b04b8a7c9e743 Mon Sep 17 00:00:00 2001
From: blmage <bl.mage.fr@gmail.com>
Date: Fri, 14 May 2021 17:41:38 +0200
Subject: [PATCH 03/12] Clean up PHP code using nikic/php-parser before
 minifying template HTML

---
 composer.json                                 |   1 +
 .../Framework/View/Template/Html/Minifier.php |  37 +++--
 .../Html/Minifier/Php/NodeVisitor.php         |  89 ++++++++++++
 .../Html/Minifier/Php/PrettyPrinter.php       | 132 ++++++++++++++++++
 4 files changed, 251 insertions(+), 8 deletions(-)
 create mode 100644 lib/internal/Magento/Framework/View/Template/Html/Minifier/Php/NodeVisitor.php
 create mode 100644 lib/internal/Magento/Framework/View/Template/Html/Minifier/Php/PrettyPrinter.php

diff --git a/composer.json b/composer.json
index 07b4e1349b958..b32efd410e686 100644
--- a/composer.json
+++ b/composer.json
@@ -65,6 +65,7 @@
         "magento/magento-composer-installer": ">=0.1.11",
         "magento/zendframework1": "dev-master as 1.14.6",
         "monolog/monolog": "^2.3",
+        "nikic/php-parser": "~4.4.0",
         "pelago/emogrifier": "^5.0.0",
         "php-amqplib/php-amqplib": "~3.0.0",
         "phpseclib/mcrypt_compat": "2.0.0",
diff --git a/lib/internal/Magento/Framework/View/Template/Html/Minifier.php b/lib/internal/Magento/Framework/View/Template/Html/Minifier.php
index ac849804dbfe6..c9f7b5a8350dd 100644
--- a/lib/internal/Magento/Framework/View/Template/Html/Minifier.php
+++ b/lib/internal/Magento/Framework/View/Template/Html/Minifier.php
@@ -9,6 +9,7 @@
 
 use Magento\Framework\App\Filesystem\DirectoryList;
 use Magento\Framework\Filesystem;
+use Magento\Framework\View\Template\Html\Minifier\Php;
 
 class Minifier implements MinifierInterface
 {
@@ -116,17 +117,37 @@ public function minify($file)
         $dir = dirname($file);
         $fileName = basename($file);
         $content = $this->readFactory->create($dir)->readFile($fileName);
+
+        $parser = (new \PhpParser\ParserFactory())->create(\PhpParser\ParserFactory::PREFER_PHP7);
+        $heredocs = null;
+
+        try {
+            $ast = $parser->parse($content);
+
+            $traverser = new \PhpParser\NodeTraverser();
+            $traverser->addVisitor(new Php\NodeVisitor());
+            $ast = $traverser->traverse($ast);
+
+            $prettyPrinter = new Php\PrettyPrinter();
+            $content = $prettyPrinter->prettyPrintFile($ast);
+            $heredocs = $prettyPrinter->getDelayedHeredocs();
+        } catch (\PhpParser\Error $error) {
+            // Some PHP code is seemingly invalid.
+        }
+
         //Storing Heredocs
-        $heredocs = [];
-        $content = preg_replace_callback(
-            '/<<<([A-z]+).*?\1\s*;/ims',
-            function ($match) use (&$heredocs) {
-                $heredocs[] = $match[0];
+        if (null === $heredocs) {
+            $content = preg_replace_callback(
+                '/<<<([A-z]+).*?\1\s*;/ims',
+                function ($match) use (&$heredocs) {
+                    $heredocs[] = $match[0];
 
-                return '__MINIFIED_HEREDOC__' .(count($heredocs) - 1);
-            },
+                    return '__MINIFIED_HEREDOC__' .(count($heredocs) - 1);
+                },
             ($content ?? '')
-        );
+            );
+        }
+
         $content = preg_replace(
             '#(?<!]]>)\s+</#',
             '</',
diff --git a/lib/internal/Magento/Framework/View/Template/Html/Minifier/Php/NodeVisitor.php b/lib/internal/Magento/Framework/View/Template/Html/Minifier/Php/NodeVisitor.php
new file mode 100644
index 0000000000000..ebb2db00f37c0
--- /dev/null
+++ b/lib/internal/Magento/Framework/View/Template/Html/Minifier/Php/NodeVisitor.php
@@ -0,0 +1,89 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+namespace Magento\Framework\View\Template\Html\Minifier\Php;
+
+use PhpParser\Comment;
+use PhpParser\Node;
+use PhpParser\NodeTraverser;
+use PhpParser\NodeVisitorAbstract;
+
+class NodeVisitor extends NodeVisitorAbstract
+{
+    /**
+     * @var Node[]
+     */
+    private $stack = [];
+
+    /**
+     * @var ?Node
+     */
+    private $previous;
+
+    /**
+     * @var int
+     */
+    private $heredocCount = 0;
+
+    public function beforeTraverse(array $nodes)
+    {
+        $this->stack = [];
+        $this->previous = null;
+    }
+
+    public function enterNode(Node $node)
+    {
+        if ($node instanceof Node\Stmt) {
+            // Mark isolated echo statements, to replace them later with short echo tags.
+            $parent = empty($this->stack) ?: $this->stack[count($this->stack) - 1];
+
+            if ($node instanceof Node\Stmt\InlineHTML) {
+                $node->setAttribute('parent', $parent);
+
+                if (
+                    ($this->previous instanceof Node\Stmt\Echo_)
+                    && ($previousHtmlStatement = $this->previous->getAttribute('previousHtmlStatement'))
+                    && ($previousHtmlStatement->getAttribute('parent') === $parent)
+                ) {
+                    $this->previous->setAttribute('isSingleEchoStatement', true);
+                    $previousHtmlStatement->setAttribute('hasSingleEchoStatementNext', true);
+                }
+            } elseif (
+                ($this->previous instanceof Node\Stmt\InlineHTML)
+                && ($this->previous->getAttribute('parent') === $parent)
+            ) {
+                $node->setAttribute('previousHtmlStatement', $this->previous);
+            }
+        }
+
+        $this->stack[] = $node;
+    }
+
+    public function leaveNode(Node $node)
+    {
+        $this->previous = $node;
+
+        array_pop($this->stack);
+
+        // Remove nodes that only contain non-doc comments.
+        if ($node instanceof Node\Stmt\Nop) {
+            $comments = $node->getComments();
+            $isSuperfluousNode = true;
+
+            foreach ($comments as $key => $comment) {
+                if ($comment instanceof Comment\Doc) {
+                    $isSuperfluousNode = false;
+                    break;
+                }
+            }
+
+            if ($isSuperfluousNode) {
+                return NodeTraverser::REMOVE_NODE;
+            }
+        }
+    }
+}
diff --git a/lib/internal/Magento/Framework/View/Template/Html/Minifier/Php/PrettyPrinter.php b/lib/internal/Magento/Framework/View/Template/Html/Minifier/Php/PrettyPrinter.php
new file mode 100644
index 0000000000000..fd15d78cea7c8
--- /dev/null
+++ b/lib/internal/Magento/Framework/View/Template/Html/Minifier/Php/PrettyPrinter.php
@@ -0,0 +1,132 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+namespace Magento\Framework\View\Template\Html\Minifier\Php;
+
+use PhpParser\Comment;
+use PhpParser\Node;
+use PhpParser\PrettyPrinter\Standard;
+
+class PrettyPrinter extends Standard
+{
+    /**
+     * @var string[]
+     */
+    private $delayedHeredocs = [];
+
+    protected function resetState()
+    {
+        $this->delayedHeredocs = [];
+        $this->indentLevel = 0;
+        $this->nl = '';
+        $this->origTokens = null;
+    }
+
+    protected function setIndentLevel(int $level)
+    {
+        // Ignore indentation.
+    }
+
+    protected function indent()
+    {
+        // Ignore indentation.
+    }
+
+    protected function outdent()
+    {
+        // Ignore indentation.
+    }
+
+    /**
+     * @param string $heredoc
+     * @return string
+     */
+    private function getHeredocPlaceholder(string $heredoc): string
+    {
+        $index = count($this->delayedHeredocs) + 1;
+
+        $this->delayedHeredocs[$index] = $this->handleMagicTokens($heredoc);
+
+        return '__MINIFIED_HEREDOC__' . $index;
+    }
+
+    protected function pScalar_String(Node\Scalar\String_ $node): string
+    {
+        $result = parent::pScalar_String($node);
+
+        return $node->getAttribute('kind') !== Node\Scalar\String_::KIND_HEREDOC
+            ? $result
+            : $this->getHeredocPlaceholder($result);
+    }
+
+    protected function pScalar_Encapsed(Node\Scalar\Encapsed $node): string
+    {
+        $result = parent::pScalar_Encapsed($node);
+
+        return $node->getAttribute('kind') !== Node\Scalar\String_::KIND_HEREDOC
+            ? $result
+            : $this->getHeredocPlaceholder($result);
+    }
+
+    protected function pCommaSeparated(array $nodes): string
+    {
+        return $this->pImplode($nodes, ',');
+    }
+
+    protected function pComments(array $comments): string
+    {
+        // Only preserve doc comments.
+        foreach ($comments as $key => $comment) {
+            if (!$comment instanceof Comment\Doc) {
+                unset($comments[$key]);
+            }
+        }
+
+        $formattedComments = [];
+
+        foreach ($comments as $comment) {
+            $formattedComments[] = str_replace("\n", '', $comment->getReformattedText());
+        }
+
+        // Add a space between doc comments to avoid occurrences of "//" that could later be misinterpreted.
+        return implode(' ', $formattedComments) . ' ';
+    }
+
+    protected function pExpr_Array(Node\Expr\Array_ $node): string
+    {
+        $node->setAttribute('kind', Node\Expr\Array_::KIND_SHORT);
+
+        return parent::pExpr_Array($node);
+    }
+
+    protected function pStmt_Echo(Node\Stmt\Echo_ $node): string
+    {
+        $output = $this->pCommaSeparated($node->exprs);
+
+        return $node->getAttribute('isSingleEchoStatement')
+            ? $output . ' '
+            : 'echo ' . $output . ';';
+    }
+
+    protected function pStmt_InlineHTML(Node\Stmt\InlineHTML $node): string
+    {
+        $newline = $node->getAttribute('hasLeadingNewline', true) ? "\n" : '';
+
+        return '?>'
+            . $newline
+            . $node->value
+            . ($node->getAttribute('hasSingleEchoStatementNext') ? '<?= ' : '<?php ');
+    }
+
+    /**
+     * @return string[]
+     */
+    public function getDelayedHeredocs(): array
+    {
+        return $this->delayedHeredocs;
+    }
+}

From e0e579199479c018cd1eedc4110de7f55a491687 Mon Sep 17 00:00:00 2001
From: blmage <bl.mage.fr@gmail.com>
Date: Sat, 15 May 2021 09:28:42 +0200
Subject: [PATCH 04/12] Remove redundant cleaning of PHP comments

---
 .../Magento/Framework/View/Template/Html/Minifier.php | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/lib/internal/Magento/Framework/View/Template/Html/Minifier.php b/lib/internal/Magento/Framework/View/Template/Html/Minifier.php
index c9f7b5a8350dd..52725921dd353 100644
--- a/lib/internal/Magento/Framework/View/Template/Html/Minifier.php
+++ b/lib/internal/Magento/Framework/View/Template/Html/Minifier.php
@@ -165,13 +165,9 @@ function ($match) use (&$heredocs) {
                             '#(?<!:|\\\\|\'|"|/)//(?!/)(?!\s*\<\!\[)(?!\s*]]\>)[^\n\r]*#',
                             '',
                             preg_replace(
-                                '#(?<!:|\'|")//[^\n\r<]*(\?\>)#',
-                                ' $1',
-                                preg_replace(
-                                    '#(?<!:)//[^\n\r]*(\<\?php)[^\n\r]*(\s\?\>)[^\n\r]*#',
-                                    '',
-                                    ($content ?? '')
-                                )
+                                '#(?<!:)//[^\n\r]*(\<\?php)[^\n\r]*(\s\?\>)[^\n\r]*#',
+                                '',
+                                ($content ?? '')
                             )
                         )
                     )
@@ -205,3 +201,4 @@ private function getRelativeGeneratedPath($sourcePath)
         return $this->filesystem->getDirectoryRead(DirectoryList::ROOT)->getRelativePath($sourcePath);
     }
 }
+

From 59dfff2c7c003e378273a535f94a758562e864b9 Mon Sep 17 00:00:00 2001
From: blmage <bl.mage.fr@gmail.com>
Date: Sat, 15 May 2021 10:03:30 +0200
Subject: [PATCH 05/12] Remove remaining single-line comments in <script> tags
 only

---
 .../Framework/View/Template/Html/Minifier.php    |  6 ++++--
 .../Test/Unit/Template/Html/MinifierTest.php     | 16 ++++++++++++++++
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/lib/internal/Magento/Framework/View/Template/Html/Minifier.php b/lib/internal/Magento/Framework/View/Template/Html/Minifier.php
index 52725921dd353..1b2a0c74a4ca5 100644
--- a/lib/internal/Magento/Framework/View/Template/Html/Minifier.php
+++ b/lib/internal/Magento/Framework/View/Template/Html/Minifier.php
@@ -162,10 +162,12 @@ function ($match) use (&$heredocs) {
                         . '(?:<(?>textarea|pre|script)\b|\z))#',
                         ' ',
                         preg_replace(
-                            '#(?<!:|\\\\|\'|"|/)//(?!/)(?!\s*\<\!\[)(?!\s*]]\>)[^\n\r]*#',
+                            '#(?<!:|\\\\|\'|"|/)//(?!/)(?!\s*\<\!\[)(?!\s*]]\>)[^\n\r]*'
+                            . '(?!(?:(?:[^<]++|<(?!/?(?:script)\b))*+)(?:<(?>script)\b|\z))#',
                             '',
                             preg_replace(
-                                '#(?<!:)//[^\n\r]*(\<\?php)[^\n\r]*(\s\?\>)[^\n\r]*#',
+                                '#(?<!:)//[^\n\r]*(\<\?php)[^\n\r]*(\s\?\>)[^\n\r]*'
+                                . '(?!(?:(?:[^<]++|<(?!/?(?:script)\b))*+)(?:<(?>script)\b|\z))#',
                                 '',
                                 ($content ?? '')
                             )
diff --git a/lib/internal/Magento/Framework/View/Test/Unit/Template/Html/MinifierTest.php b/lib/internal/Magento/Framework/View/Test/Unit/Template/Html/MinifierTest.php
index 87ac7b484c182..6bd3b1d9c0ace 100644
--- a/lib/internal/Magento/Framework/View/Test/Unit/Template/Html/MinifierTest.php
+++ b/lib/internal/Magento/Framework/View/Test/Unit/Template/Html/MinifierTest.php
@@ -133,6 +133,9 @@ public function testMinify(): void
  */
 ?>
 <?php //one line comment ?>
+<?php //one line comment containing a <span> ?>
+<?php /** multi line comment containing a <span> */ ?>
+<?php echo 'test'; ?>
 <html>
     <head>
         <title>Test title</title>
@@ -180,8 +183,21 @@ public function testMinify(): void
     \$sometext = <<<SOMETEXT
     mytext
     mytextline2
+    <span>   </span>
 SOMETEXT;
     ?>
+    <div>
+        // This is not a comment and should be preserved.
+        // This is not a comment <?= 'either.' ?>
+    </div>
+    <?php
+    \$someothertext = <<<SOMEOTHERTEXT
+    mytext
+    {\$block->getChildHtml('someChildBlock')}
+    <span>   </span>
+SOMEOTHERTEXT
+;
+    ?>
 </html>
 TEXT;
 

From 06f667b5bbc2782002ba68bf58cfdc1e881680c4 Mon Sep 17 00:00:00 2001
From: blmage <bl.mage.fr@gmail.com>
Date: Sat, 15 May 2021 10:04:32 +0200
Subject: [PATCH 06/12] Improve detection of commented PHP tags

---
 lib/internal/Magento/Framework/View/Template/Html/Minifier.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/internal/Magento/Framework/View/Template/Html/Minifier.php b/lib/internal/Magento/Framework/View/Template/Html/Minifier.php
index 1b2a0c74a4ca5..5edf3f83780fc 100644
--- a/lib/internal/Magento/Framework/View/Template/Html/Minifier.php
+++ b/lib/internal/Magento/Framework/View/Template/Html/Minifier.php
@@ -166,7 +166,7 @@ function ($match) use (&$heredocs) {
                             . '(?!(?:(?:[^<]++|<(?!/?(?:script)\b))*+)(?:<(?>script)\b|\z))#',
                             '',
                             preg_replace(
-                                '#(?<!:)//[^\n\r]*(\<\?php)[^\n\r]*(\s\?\>)[^\n\r]*'
+                                '#(?<!:)//[^\n\r]*(\<\?(php|=))[^\n\r]*(\s\?\>)[^\n\r]*'
                                 . '(?!(?:(?:[^<]++|<(?!/?(?:script)\b))*+)(?:<(?>script)\b|\z))#',
                                 '',
                                 ($content ?? '')

From 5fbf10b1ae8b45a909b983958d1e98adcf767a45 Mon Sep 17 00:00:00 2001
From: blmage <bl.mage.fr@gmail.com>
Date: Sat, 15 May 2021 10:08:15 +0200
Subject: [PATCH 07/12] Do not break JS RegExps that look like comments

For example, prevent "/\/path\/to\//" from being replaced with "/\/path\/to\"
---
 .../Magento/Framework/View/Template/Html/Minifier.php         | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/internal/Magento/Framework/View/Template/Html/Minifier.php b/lib/internal/Magento/Framework/View/Template/Html/Minifier.php
index 5edf3f83780fc..91274d0815035 100644
--- a/lib/internal/Magento/Framework/View/Template/Html/Minifier.php
+++ b/lib/internal/Magento/Framework/View/Template/Html/Minifier.php
@@ -162,11 +162,11 @@ function ($match) use (&$heredocs) {
                         . '(?:<(?>textarea|pre|script)\b|\z))#',
                         ' ',
                         preg_replace(
-                            '#(?<!:|\\\\|\'|"|/)//(?!/)(?!\s*\<\!\[)(?!\s*]]\>)[^\n\r]*'
+                            '#(?<!:|\\\\|\\\|\'|"|/)//(?!/)(?!\s*\<\!\[)(?!\s*]]\>)[^\n\r]*'
                             . '(?!(?:(?:[^<]++|<(?!/?(?:script)\b))*+)(?:<(?>script)\b|\z))#',
                             '',
                             preg_replace(
-                                '#(?<!:)//[^\n\r]*(\<\?(php|=))[^\n\r]*(\s\?\>)[^\n\r]*'
+                                '#(?<!:|\\\)//[^\n\r]*(\<\?(php|=))[^\n\r]*(\s\?\>)[^\n\r]*'
                                 . '(?!(?:(?:[^<]++|<(?!/?(?:script)\b))*+)(?:<(?>script)\b|\z))#',
                                 '',
                                 ($content ?? '')

From 9062eb7094383cf405d4186d1fb8348b26b88f6d Mon Sep 17 00:00:00 2001
From: blmage <bl.mage.fr@gmail.com>
Date: Sat, 15 May 2021 14:55:49 +0200
Subject: [PATCH 08/12] Handle edge cases when parsing templates

- Do not attempt to parse empty contents
- Prevent nesting problems with Xdebug
- Catch and silence errors
---
 .../Framework/View/Template/Html/Minifier.php | 44 +++++++++++++------
 1 file changed, 30 insertions(+), 14 deletions(-)

diff --git a/lib/internal/Magento/Framework/View/Template/Html/Minifier.php b/lib/internal/Magento/Framework/View/Template/Html/Minifier.php
index 91274d0815035..a753fe23e3003 100644
--- a/lib/internal/Magento/Framework/View/Template/Html/Minifier.php
+++ b/lib/internal/Magento/Framework/View/Template/Html/Minifier.php
@@ -117,22 +117,38 @@ public function minify($file)
         $dir = dirname($file);
         $fileName = basename($file);
         $content = $this->readFactory->create($dir)->readFile($fileName);
-
-        $parser = (new \PhpParser\ParserFactory())->create(\PhpParser\ParserFactory::PREFER_PHP7);
         $heredocs = null;
 
-        try {
-            $ast = $parser->parse($content);
-
-            $traverser = new \PhpParser\NodeTraverser();
-            $traverser->addVisitor(new Php\NodeVisitor());
-            $ast = $traverser->traverse($ast);
-
-            $prettyPrinter = new Php\PrettyPrinter();
-            $content = $prettyPrinter->prettyPrintFile($ast);
-            $heredocs = $prettyPrinter->getDelayedHeredocs();
-        } catch (\PhpParser\Error $error) {
-            // Some PHP code is seemingly invalid.
+        if (null !== $content) {
+            $parser = (new \PhpParser\ParserFactory())->create(\PhpParser\ParserFactory::PREFER_PHP7);
+
+            /**
+             * Prevent problems with deeply nested ASTs if xDebug is enabled.
+             * @see https://github.com/nikic/PHP-Parser/blob/v4.4.0/doc/2_Usage_of_basic_components.markdown#bootstrapping
+             */
+            $nestingLevelConfigValue = ini_get('xdebug.max_nesting_level');
+
+            if (false !== $nestingLevelConfigValue) {
+                ini_set('xdebug.max_nesting_level', '3000');
+            }
+
+            try {
+                $ast = $parser->parse($content);
+
+                $traverser = new \PhpParser\NodeTraverser();
+                $traverser->addVisitor(new Php\NodeVisitor());
+                $ast = $traverser->traverse($ast);
+
+                $prettyPrinter = new Php\PrettyPrinter();
+                $content = $prettyPrinter->prettyPrintFile($ast);
+                $heredocs = $prettyPrinter->getDelayedHeredocs();
+            } catch (\Error $error) {
+                // Some PHP code is seemingly invalid, or too complex.
+            } finally {
+                if (false !== $nestingLevelConfigValue) {
+                    ini_set('xdebug.max_nesting_level', $nestingLevelConfigValue);
+                }
+            }
         }
 
         //Storing Heredocs

From 1bc9e69f872ceef8f2b0c4fc16bf0cb967ea1de8 Mon Sep 17 00:00:00 2001
From: blmage <bl.mage.fr@gmail.com>
Date: Sat, 15 May 2021 14:57:18 +0200
Subject: [PATCH 09/12] Preserve all spaces inside <textarea> and <pre> tags

---
 lib/internal/Magento/Framework/View/Template/Html/Minifier.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/internal/Magento/Framework/View/Template/Html/Minifier.php b/lib/internal/Magento/Framework/View/Template/Html/Minifier.php
index a753fe23e3003..a9dff43631926 100644
--- a/lib/internal/Magento/Framework/View/Template/Html/Minifier.php
+++ b/lib/internal/Magento/Framework/View/Template/Html/Minifier.php
@@ -165,7 +165,7 @@ function ($match) use (&$heredocs) {
         }
 
         $content = preg_replace(
-            '#(?<!]]>)\s+</#',
+            '#(?<!]]>)\s+</(?!(?>textarea|pre)\b)#',
             '</',
             preg_replace(
                 '#((?:<\?php\s+(?!echo|print|if|elseif|else)[^\?]*)\?>)\s+#',

From 59be88403dd3e8395d10fcecee9404b734f8e2ef Mon Sep 17 00:00:00 2001
From: blmage <bl.mage.fr@gmail.com>
Date: Sat, 15 May 2021 15:09:06 +0200
Subject: [PATCH 10/12] Comment on each step of the minification process

---
 .../Framework/View/Template/Html/Minifier.php   | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/lib/internal/Magento/Framework/View/Template/Html/Minifier.php b/lib/internal/Magento/Framework/View/Template/Html/Minifier.php
index a9dff43631926..fb3f2d476dd04 100644
--- a/lib/internal/Magento/Framework/View/Template/Html/Minifier.php
+++ b/lib/internal/Magento/Framework/View/Template/Html/Minifier.php
@@ -119,11 +119,12 @@ public function minify($file)
         $content = $this->readFactory->create($dir)->readFile($fileName);
         $heredocs = null;
 
+        // Safely minify PHP code and remove single-line PHP comments by using a parser.
         if (null !== $content) {
             $parser = (new \PhpParser\ParserFactory())->create(\PhpParser\ParserFactory::PREFER_PHP7);
 
             /**
-             * Prevent problems with deeply nested ASTs if xDebug is enabled.
+             * Prevent problems with deeply nested ASTs if Xdebug is enabled.
              * @see https://github.com/nikic/PHP-Parser/blob/v4.4.0/doc/2_Usage_of_basic_components.markdown#bootstrapping
              */
             $nestingLevelConfigValue = ini_get('xdebug.max_nesting_level');
@@ -151,7 +152,7 @@ public function minify($file)
             }
         }
 
-        //Storing Heredocs
+        // Stash the heredocs now if the template could not be parsed.
         if (null === $heredocs) {
             $content = preg_replace_callback(
                 '/<<<([A-z]+).*?\1\s*;/ims',
@@ -164,23 +165,33 @@ function ($match) use (&$heredocs) {
             );
         }
 
+        // Remove insignificant spaces before closing HTML tags
+        // (preserve one space after ]]>, and all spaces inside <pre> and <textarea> tags).
         $content = preg_replace(
             '#(?<!]]>)\s+</(?!(?>textarea|pre)\b)#',
             '</',
+            // Remove redundant spaces after PHP tags that do not start with a print or condition statement,
+            // and that do not contain any "?".
             preg_replace(
                 '#((?:<\?php\s+(?!echo|print|if|elseif|else)[^\?]*)\?>)\s+#',
                 '$1 ',
+                // Remove single space in empty non-inline tags.
                 preg_replace(
                     '#(?<!' . implode('|', $this->inlineHtmlTags) . ')\> \<#',
                     '><',
+                    // Remove redundant spaces outside of tags in which they are relevant.
                     preg_replace(
                         '#(?ix)(?>[^\S ]\s*|\s{2,})(?=(?:(?:[^<]++|<(?!/?(?:textarea|pre|script)\b))*+)'
                         . '(?:<(?>textarea|pre|script)\b|\z))#',
                         ' ',
+                        // Remove single-line comments in <script> tags, except for <![CDATA[ and ]]>.
+                        // Do nothing if the "//" part is seemingly part of a string / URL / RegExp.
                         preg_replace(
                             '#(?<!:|\\\\|\\\|\'|"|/)//(?!/)(?!\s*\<\!\[)(?!\s*]]\>)[^\n\r]*'
                             . '(?!(?:(?:[^<]++|<(?!/?(?:script)\b))*+)(?:<(?>script)\b|\z))#',
                             '',
+                            // Remove commented single-line PHP tags in <script> tags.
+                            // Do nothing if the "//" part is seemingly part of a URL / RegExp.
                             preg_replace(
                                 '#(?<!:|\\\)//[^\n\r]*(\<\?(php|=))[^\n\r]*(\s\?\>)[^\n\r]*'
                                 . '(?!(?:(?:[^<]++|<(?!/?(?:script)\b))*+)(?:<(?>script)\b|\z))#',
@@ -193,7 +204,7 @@ function ($match) use (&$heredocs) {
             )
         );
 
-        //Restoring Heredocs
+        // Restore the stashed heredocs.
         $content = preg_replace_callback(
             '/__MINIFIED_HEREDOC__(\d+)/ims',
             function ($match) use ($heredocs) {

From 1ac88c3ae14857cbcce00f80a1e48316b0b5d6c6 Mon Sep 17 00:00:00 2001
From: blmage <bl.mage.fr@gmail.com>
Date: Sat, 15 May 2021 15:11:00 +0200
Subject: [PATCH 11/12] Update template minifier tests

---
 .../Test/Unit/Template/Html/MinifierTest.php  | 27 +++++++++++++++----
 1 file changed, 22 insertions(+), 5 deletions(-)

diff --git a/lib/internal/Magento/Framework/View/Test/Unit/Template/Html/MinifierTest.php b/lib/internal/Magento/Framework/View/Test/Unit/Template/Html/MinifierTest.php
index 6bd3b1d9c0ace..94b26096eafcf 100644
--- a/lib/internal/Magento/Framework/View/Test/Unit/Template/Html/MinifierTest.php
+++ b/lib/internal/Magento/Framework/View/Test/Unit/Template/Html/MinifierTest.php
@@ -173,7 +173,7 @@ public function testMinify(): void
         <?php echo '//some.link.com/' ?>
         <em>inline text</em>
         <a href="http://www.<?php echo 'hi' ?>"></a>
-        <?php// if (\$block->getSomeVariable() > 1):?>
+        <?php // if (\$block->getSomeVariable() > 1):?>
             <?php echo \$block->getChildHtml('someChildBlock'); ?>
         <?php //else:?>
             <?php // echo \$block->getChildHtml('anotherChildBlock'); ?>
@@ -190,6 +190,12 @@ public function testMinify(): void
         // This is not a comment and should be preserved.
         // This is not a comment <?= 'either.' ?>
     </div>
+    <textarea>
+        Spaces in textareas
+        are significant and
+        should not be removed.
+    </textarea>
+    This is HTML : <?php//
     <?php
     \$someothertext = <<<SOMEOTHERTEXT
     mytext
@@ -202,7 +208,7 @@ public function testMinify(): void
 TEXT;
 
         $expectedContent = <<<TEXT
-<?php /** * Copyright © Magento, Inc. All rights reserved. * See COPYING.txt for license details. */ ?> <?php ?> <html><head><title>Test title</title></head><link rel="stylesheet" href='https://www.example.com/2' type="text/css" /><link rel="stylesheet" type="text/css" media="all" href="https://www.example.com/1" type="text/css" /><body><a href="http://somelink.com/text.html">Text Link</a> <img src="test.png" alt="some text" /><?php echo \$block->someMethod(); ?> <img src="data:image/gif;base64,P///yH5BAEAAAA" data-component="main-image"><?= \$block->someMethod(); ?> <div style="width: 800px" class="<?php echo \$block->getClass() ?>" /><img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" data-component="main-image"><script>
+<?php /** * Copyright © Magento, Inc. All rights reserved. * See COPYING.txt for license details. */ /** multi line comment containing a <span> */ echo 'test';?> <html><head><title>Test title</title></head><link rel="stylesheet" href='https://www.example.com/2' type="text/css" /><link rel="stylesheet" type="text/css" media="all" href="https://www.example.com/1" type="text/css" /><body><a href="http://somelink.com/text.html">Text Link</a> <img src="test.png" alt="some text" /><?= \$block->someMethod() ?> <img src="data:image/gif;base64,P///yH5BAEAAAA" data-component="main-image"><?= \$block->someMethod() ?> <div style="width: 800px" class="<?= \$block->getClass() ?>" /><img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" data-component="main-image"><script>
             var i = 1;
             var j = 1;
 
@@ -215,15 +221,26 @@ public function testMinify(): void
                 return {
                     'someProperty': test,
                     'someMethod': function () {
-                        alert(<?php echo \$block->getJsAlert() ?>);
+                        alert(<?= \$block->getJsAlert() ?>);
                     }
                 }
             });
             //]]>
-</script><?php echo "http://some.link.com/" ?> <?php echo "//some.link.com/" ?> <?php echo '//some.link.com/' ?> <em>inline text</em> <a href="http://www.<?php echo 'hi' ?>"></a> <?php ?> <?php echo \$block->getChildHtml('someChildBlock'); ?> <?php ?> <?php ?> <?php ?></body><?php \$sometext = <<<SOMETEXT
+</script><?= "http://some.link.com/" ?> <?= "//some.link.com/" ?> <?= '//some.link.com/' ?> <em>inline text</em> <a href="http://www.<?= 'hi' ?>"></a> <?php ?> <?= \$block->getChildHtml('someChildBlock') ?> <?php ?> <?php ?> <?php ?></body><?php \$sometext = <<<SOMETEXT
     mytext
     mytextline2
-SOMETEXT; ?></html>
+    <span>   </span>
+SOMETEXT
+;?> <div> // This is not a comment and should be preserved. // This is not a comment <?= 'either.' ?></div><textarea>
+        Spaces in textareas
+        are significant and
+        should not be removed.
+    </textarea> This is HTML : <?php// <?php \$someothertext = <<<SOMEOTHERTEXT
+    mytext
+    {\$block->getChildHtml('someChildBlock')}
+    <span>   </span>
+SOMEOTHERTEXT
+;?></html>
 TEXT;
 
         $this->appDirectoryMock->expects($this->once())

From 4e50effeae3a00e1e87047b3c272096f578b4ece Mon Sep 17 00:00:00 2001
From: blmage <bl.mage.fr@gmail.com>
Date: Sat, 15 May 2021 15:34:52 +0200
Subject: [PATCH 12/12] Remove unused variable

---
 .../View/Template/Html/Minifier/Php/NodeVisitor.php          | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/lib/internal/Magento/Framework/View/Template/Html/Minifier/Php/NodeVisitor.php b/lib/internal/Magento/Framework/View/Template/Html/Minifier/Php/NodeVisitor.php
index ebb2db00f37c0..e127e323b49a5 100644
--- a/lib/internal/Magento/Framework/View/Template/Html/Minifier/Php/NodeVisitor.php
+++ b/lib/internal/Magento/Framework/View/Template/Html/Minifier/Php/NodeVisitor.php
@@ -24,11 +24,6 @@ class NodeVisitor extends NodeVisitorAbstract
      */
     private $previous;
 
-    /**
-     * @var int
-     */
-    private $heredocCount = 0;
-
     public function beforeTraverse(array $nodes)
     {
         $this->stack = [];