From 9b93547648ef3ad22327dd2d03e8007bed84488e Mon Sep 17 00:00:00 2001
From: Oliver Pike <oliver@hipocampo.com>
Date: Thu, 11 May 2023 14:33:18 -0700
Subject: [PATCH 1/4] Fixes less#3675 - LESS detects @apply as variable (ISSUE)

---
 packages/less/src/less/tree/expression.js           | 13 +++++++++++--
 packages/less/src/less/tree/variable.js             |  3 +--
 .../test/browser/css/atrule-passthrough/test.css    |  5 +++++
 .../less/test/browser/generator/runner.config.js    | 12 ++++++++++--
 .../test/browser/less/atrule-passthrough/test.less  |  5 +++++
 .../browser/runner-atrule-passthrough-options.js    |  4 ++++
 .../test/browser/runner-atrule-passthrough-spec.js  |  3 +++
 7 files changed, 39 insertions(+), 6 deletions(-)
 create mode 100644 packages/less/test/browser/css/atrule-passthrough/test.css
 create mode 100644 packages/less/test/browser/less/atrule-passthrough/test.less
 create mode 100644 packages/less/test/browser/runner-atrule-passthrough-options.js
 create mode 100644 packages/less/test/browser/runner-atrule-passthrough-spec.js

diff --git a/packages/less/src/less/tree/expression.js b/packages/less/src/less/tree/expression.js
index 957505b872..4b3ddd8e83 100644
--- a/packages/less/src/less/tree/expression.js
+++ b/packages/less/src/less/tree/expression.js
@@ -38,14 +38,23 @@ Expression.prototype = Object.assign(new Node(), {
             if (this.value[0].parens && !this.value[0].parensInOp && !context.inCalc) {
                 doubleParen = true;
             }
-            returnValue = this.value[0].eval(context);
+            try {
+                returnValue = this.value[0].eval(context);
+            } catch (e) {
+                // Pass through at-rules to the css file.
+                if (e.type === 'PassThrough') {
+                    returnValue = this;
+                } else {
+                    throw e;
+                }
+            }
         } else {
             returnValue = this;
         }
         if (inParenthesis) {
             context.outOfParenthesis();
         }
-        if (this.parens && this.parensInOp && !mathOn && !doubleParen 
+        if (this.parens && this.parensInOp && !mathOn && !doubleParen
             && (!(returnValue instanceof Dimension))) {
             returnValue = new Paren(returnValue);
         }
diff --git a/packages/less/src/less/tree/variable.js b/packages/less/src/less/tree/variable.js
index a81e3ecef0..460356f5c5 100644
--- a/packages/less/src/less/tree/variable.js
+++ b/packages/less/src/less/tree/variable.js
@@ -46,8 +46,7 @@ Variable.prototype = Object.assign(new Node(), {
             this.evaluating = false;
             return variable;
         } else {
-            throw { type: 'Name',
-                message: `variable ${name} is undefined`,
+            throw { type: 'PassThrough',
                 filename: this.fileInfo().filename,
                 index: this.getIndex() };
         }
diff --git a/packages/less/test/browser/css/atrule-passthrough/test.css b/packages/less/test/browser/css/atrule-passthrough/test.css
new file mode 100644
index 0000000000..9dd26b8607
--- /dev/null
+++ b/packages/less/test/browser/css/atrule-passthrough/test.css
@@ -0,0 +1,5 @@
+.test {
+    --iron-autogrow-textarea: {
+    @apply --app-font-monospace;
+    }
+}
diff --git a/packages/less/test/browser/generator/runner.config.js b/packages/less/test/browser/generator/runner.config.js
index 8dc30ed58c..d1c1723ae7 100644
--- a/packages/less/test/browser/generator/runner.config.js
+++ b/packages/less/test/browser/generator/runner.config.js
@@ -138,6 +138,14 @@ module.exports = {
             outfile: 'tmp/browser/test-runner-global-vars.html'
         }
     },
+    atrulePassthrough: {
+        src: ['test/browser/less/atrule-passthrough/*.less'],
+        options: {
+            helpers: 'test/browser/runner-atrule-passthrough-options.js',
+            specs: 'test/browser/runner-atrule-passthrough-spec.js',
+            outfile: 'tmp/browser/test-runner-atrule-passthrough.html'
+        }
+    },
     postProcessorPlugin: {
         src: [`${lessFolder}/postProcessorPlugin/*.less`],
         options: {
@@ -182,5 +190,5 @@ module.exports = {
             specs: 'test/browser/runner-filemanagerPlugin.js',
             outfile: 'tmp/browser/test-runner-filemanager-plugin.html'
         }
-    }
-}
\ No newline at end of file
+    },
+}
diff --git a/packages/less/test/browser/less/atrule-passthrough/test.less b/packages/less/test/browser/less/atrule-passthrough/test.less
new file mode 100644
index 0000000000..9dd26b8607
--- /dev/null
+++ b/packages/less/test/browser/less/atrule-passthrough/test.less
@@ -0,0 +1,5 @@
+.test {
+    --iron-autogrow-textarea: {
+    @apply --app-font-monospace;
+    }
+}
diff --git a/packages/less/test/browser/runner-atrule-passthrough-options.js b/packages/less/test/browser/runner-atrule-passthrough-options.js
new file mode 100644
index 0000000000..85b1d5a001
--- /dev/null
+++ b/packages/less/test/browser/runner-atrule-passthrough-options.js
@@ -0,0 +1,4 @@
+var less = {
+    logLevel: 4,
+    errorReporting: 'console'
+};
diff --git a/packages/less/test/browser/runner-atrule-passthrough-spec.js b/packages/less/test/browser/runner-atrule-passthrough-spec.js
new file mode 100644
index 0000000000..73584512d3
--- /dev/null
+++ b/packages/less/test/browser/runner-atrule-passthrough-spec.js
@@ -0,0 +1,3 @@
+describe('less.js atrule passthrough', function () {
+    testLessEqualsInDocument();
+});

From 00e7de3f84eb05d571c08020c9e31230ded7e7bc Mon Sep 17 00:00:00 2001
From: Oliver Pike <oliver@hipocampo.com>
Date: Fri, 12 May 2023 05:49:19 -0700
Subject: [PATCH 2/4] Fixes less#3675 - LESS detects @apply as variable (ISSUE)

---
 packages/less/src/less/tree/quoted.js                 | 10 +++++++++-
 packages/less/src/less/tree/variable.js               |  3 ++-
 packages/test-data/css/_main/atrule-passthrough.css   |  5 +++++
 packages/test-data/less/_main/atrule-passthrough.less |  5 +++++
 4 files changed, 21 insertions(+), 2 deletions(-)
 create mode 100644 packages/test-data/css/_main/atrule-passthrough.css
 create mode 100644 packages/test-data/less/_main/atrule-passthrough.less

diff --git a/packages/less/src/less/tree/quoted.js b/packages/less/src/less/tree/quoted.js
index cb0d56b12f..c6dbfd738e 100644
--- a/packages/less/src/less/tree/quoted.js
+++ b/packages/less/src/less/tree/quoted.js
@@ -34,7 +34,15 @@ Quoted.prototype = Object.assign(new Node(), {
         const that = this;
         let value = this.value;
         const variableReplacement = function (_, name) {
-            const v = new Variable(`@${name}`, that.getIndex(), that.fileInfo()).eval(context, true);
+            let v;
+            try {
+                v = new Variable(`@${name}`, that.getIndex(), that.fileInfo()).eval(context, true);
+            } catch (e) {
+                if (e.type !== 'Name') {
+                    throw e;
+                }
+                return `@${name}`;
+            }
             return (v instanceof Quoted) ? v.value : v.toCSS();
         };
         const propertyReplacement = function (_, name) {
diff --git a/packages/less/src/less/tree/variable.js b/packages/less/src/less/tree/variable.js
index 460356f5c5..a81e3ecef0 100644
--- a/packages/less/src/less/tree/variable.js
+++ b/packages/less/src/less/tree/variable.js
@@ -46,7 +46,8 @@ Variable.prototype = Object.assign(new Node(), {
             this.evaluating = false;
             return variable;
         } else {
-            throw { type: 'PassThrough',
+            throw { type: 'Name',
+                message: `variable ${name} is undefined`,
                 filename: this.fileInfo().filename,
                 index: this.getIndex() };
         }
diff --git a/packages/test-data/css/_main/atrule-passthrough.css b/packages/test-data/css/_main/atrule-passthrough.css
new file mode 100644
index 0000000000..db0bdd0dd9
--- /dev/null
+++ b/packages/test-data/css/_main/atrule-passthrough.css
@@ -0,0 +1,5 @@
+.test {
+  --iron-autogrow-textarea: {
+    @apply --app-font-monospace;
+    };
+}
diff --git a/packages/test-data/less/_main/atrule-passthrough.less b/packages/test-data/less/_main/atrule-passthrough.less
new file mode 100644
index 0000000000..9dd26b8607
--- /dev/null
+++ b/packages/test-data/less/_main/atrule-passthrough.less
@@ -0,0 +1,5 @@
+.test {
+    --iron-autogrow-textarea: {
+    @apply --app-font-monospace;
+    }
+}

From 7cf515abac3fdac9f3be8adfad62734b01ccc60a Mon Sep 17 00:00:00 2001
From: Oliver Pike <oliver@hipocampo.com>
Date: Fri, 12 May 2023 06:08:20 -0700
Subject: [PATCH 3/4] Fixes less#3675 - LESS detects @apply as variable (ISSUE)

---
 packages/less/test/browser/generator/runner.config.js | 8 --------
 packages/test-data/less/_main/atrule-passthrough.less | 2 +-
 2 files changed, 1 insertion(+), 9 deletions(-)

diff --git a/packages/less/test/browser/generator/runner.config.js b/packages/less/test/browser/generator/runner.config.js
index d1c1723ae7..8e63cde3e3 100644
--- a/packages/less/test/browser/generator/runner.config.js
+++ b/packages/less/test/browser/generator/runner.config.js
@@ -138,14 +138,6 @@ module.exports = {
             outfile: 'tmp/browser/test-runner-global-vars.html'
         }
     },
-    atrulePassthrough: {
-        src: ['test/browser/less/atrule-passthrough/*.less'],
-        options: {
-            helpers: 'test/browser/runner-atrule-passthrough-options.js',
-            specs: 'test/browser/runner-atrule-passthrough-spec.js',
-            outfile: 'tmp/browser/test-runner-atrule-passthrough.html'
-        }
-    },
     postProcessorPlugin: {
         src: [`${lessFolder}/postProcessorPlugin/*.less`],
         options: {
diff --git a/packages/test-data/less/_main/atrule-passthrough.less b/packages/test-data/less/_main/atrule-passthrough.less
index 9dd26b8607..25bea9210d 100644
--- a/packages/test-data/less/_main/atrule-passthrough.less
+++ b/packages/test-data/less/_main/atrule-passthrough.less
@@ -1,5 +1,5 @@
 .test {
-    --iron-autogrow-textarea: {
+  --iron-autogrow-textarea: {
     @apply --app-font-monospace;
     }
 }

From 004abf3f1d3064fcaeb758bfe037ec471668a4d2 Mon Sep 17 00:00:00 2001
From: Oliver Pike <oliver@hipocampo.com>
Date: Fri, 12 May 2023 06:21:12 -0700
Subject: [PATCH 4/4] Fixes less#3675 - LESS detects @apply as variable (ISSUE)

---
 packages/less/src/less/tree/expression.js             | 11 +----------
 .../less/test/browser/css/atrule-passthrough/test.css |  5 -----
 packages/less/test/browser/generator/runner.config.js |  2 +-
 .../test/browser/less/atrule-passthrough/test.less    |  5 -----
 .../test/browser/runner-atrule-passthrough-options.js |  4 ----
 .../test/browser/runner-atrule-passthrough-spec.js    |  3 ---
 6 files changed, 2 insertions(+), 28 deletions(-)
 delete mode 100644 packages/less/test/browser/css/atrule-passthrough/test.css
 delete mode 100644 packages/less/test/browser/less/atrule-passthrough/test.less
 delete mode 100644 packages/less/test/browser/runner-atrule-passthrough-options.js
 delete mode 100644 packages/less/test/browser/runner-atrule-passthrough-spec.js

diff --git a/packages/less/src/less/tree/expression.js b/packages/less/src/less/tree/expression.js
index 4b3ddd8e83..121492f9cc 100644
--- a/packages/less/src/less/tree/expression.js
+++ b/packages/less/src/less/tree/expression.js
@@ -38,16 +38,7 @@ Expression.prototype = Object.assign(new Node(), {
             if (this.value[0].parens && !this.value[0].parensInOp && !context.inCalc) {
                 doubleParen = true;
             }
-            try {
-                returnValue = this.value[0].eval(context);
-            } catch (e) {
-                // Pass through at-rules to the css file.
-                if (e.type === 'PassThrough') {
-                    returnValue = this;
-                } else {
-                    throw e;
-                }
-            }
+            returnValue = this.value[0].eval(context);
         } else {
             returnValue = this;
         }
diff --git a/packages/less/test/browser/css/atrule-passthrough/test.css b/packages/less/test/browser/css/atrule-passthrough/test.css
deleted file mode 100644
index 9dd26b8607..0000000000
--- a/packages/less/test/browser/css/atrule-passthrough/test.css
+++ /dev/null
@@ -1,5 +0,0 @@
-.test {
-    --iron-autogrow-textarea: {
-    @apply --app-font-monospace;
-    }
-}
diff --git a/packages/less/test/browser/generator/runner.config.js b/packages/less/test/browser/generator/runner.config.js
index 8e63cde3e3..f78d87e21e 100644
--- a/packages/less/test/browser/generator/runner.config.js
+++ b/packages/less/test/browser/generator/runner.config.js
@@ -182,5 +182,5 @@ module.exports = {
             specs: 'test/browser/runner-filemanagerPlugin.js',
             outfile: 'tmp/browser/test-runner-filemanager-plugin.html'
         }
-    },
+    }
 }
diff --git a/packages/less/test/browser/less/atrule-passthrough/test.less b/packages/less/test/browser/less/atrule-passthrough/test.less
deleted file mode 100644
index 9dd26b8607..0000000000
--- a/packages/less/test/browser/less/atrule-passthrough/test.less
+++ /dev/null
@@ -1,5 +0,0 @@
-.test {
-    --iron-autogrow-textarea: {
-    @apply --app-font-monospace;
-    }
-}
diff --git a/packages/less/test/browser/runner-atrule-passthrough-options.js b/packages/less/test/browser/runner-atrule-passthrough-options.js
deleted file mode 100644
index 85b1d5a001..0000000000
--- a/packages/less/test/browser/runner-atrule-passthrough-options.js
+++ /dev/null
@@ -1,4 +0,0 @@
-var less = {
-    logLevel: 4,
-    errorReporting: 'console'
-};
diff --git a/packages/less/test/browser/runner-atrule-passthrough-spec.js b/packages/less/test/browser/runner-atrule-passthrough-spec.js
deleted file mode 100644
index 73584512d3..0000000000
--- a/packages/less/test/browser/runner-atrule-passthrough-spec.js
+++ /dev/null
@@ -1,3 +0,0 @@
-describe('less.js atrule passthrough', function () {
-    testLessEqualsInDocument();
-});