From b2b37e04e4d861901bb76781d34faa638a251a35 Mon Sep 17 00:00:00 2001
From: Jordan Pittman <jordan@cryptica.me>
Date: Fri, 1 Dec 2023 10:22:45 -0500
Subject: [PATCH] Don't crash when given applying a variant to a negated
 version of a simple utility (#12514)

* Don't crash when given applying a variant to a negated version of a simple utility

* Update changelog
---
 CHANGELOG.md                  |  1 +
 src/lib/generateRules.js      |  5 +++++
 tests/negative-prefix.test.js | 20 ++++++++++++++++++++
 3 files changed, 26 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0ec3e7812580..180fad7acdb6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -14,6 +14,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Don't emit `@config` in CSS when watching via the CLI ([#12327](https://github.com/tailwindlabs/tailwindcss/pull/12327))
 - Ensure configured `font-feature-settings` for `mono` are included in Preflight ([#12342](https://github.com/tailwindlabs/tailwindcss/pull/12342))
 - Improve candidate detection in minified JS arrays (without spaces) ([#12396](https://github.com/tailwindlabs/tailwindcss/pull/12396))
+- Don't crash when given applying a variant to a negated version of a simple utility ([#12514](https://github.com/tailwindlabs/tailwindcss/pull/12514))
 - [Oxide] Remove `autoprefixer` dependency ([#11315](https://github.com/tailwindlabs/tailwindcss/pull/11315))
 - [Oxide] Fix source maps issue resulting in a crash ([#11319](https://github.com/tailwindlabs/tailwindcss/pull/11319))
 - [Oxide] Fallback to RegEx based parser when using custom transformers or extractors ([#11335](https://github.com/tailwindlabs/tailwindcss/pull/11335))
diff --git a/src/lib/generateRules.js b/src/lib/generateRules.js
index ff838190bf67..ac9fbb11926e 100644
--- a/src/lib/generateRules.js
+++ b/src/lib/generateRules.js
@@ -840,6 +840,11 @@ function applyFinalFormat(match, { context, candidate }) {
     return null
   }
 
+  // If all rules have been eliminated we can skip this candidate entirely
+  if (container.nodes.length === 0) {
+    return null
+  }
+
   match[1] = container.nodes[0]
 
   return match
diff --git a/tests/negative-prefix.test.js b/tests/negative-prefix.test.js
index 615558807391..edd5b7aaa4f6 100644
--- a/tests/negative-prefix.test.js
+++ b/tests/negative-prefix.test.js
@@ -339,4 +339,24 @@ test('arbitrary value keywords should be ignored', () => {
   return run('@tailwind utilities', config).then((result) => {
     return expect(result.css).toMatchFormattedCss(css``)
   })
+
+  // This is a weird test but it used to crash because the negative prefix + variant used to cause an undefined utility to be generated
+  test('addUtilities without negative prefix + variant + negative prefix in content should not crash', async () => {
+    let config = {
+      content: [{ raw: html`<div class="hover:-top-lg"></div>` }],
+      plugins: [
+        ({ addUtilities }) => {
+          addUtilities({
+            '.top-lg': {
+              top: '6rem',
+            },
+          })
+        },
+      ],
+    }
+
+    let result = await run('@tailwind utilities', config)
+
+    expect(result.css).toMatchCss(css``)
+  })
 })