From 52a67abea5b6c1735b4369e2e0745acc406ec3ce Mon Sep 17 00:00:00 2001
From: Richard Hallows <jeddy3@users.noreply.github.com>
Date: Wed, 19 May 2021 13:16:34 +0100
Subject: [PATCH] Fix false positives for flex in length-zero-no-unit (#5315)

---
 lib/rules/length-zero-no-unit/__tests__/index.js | 8 ++++++++
 lib/rules/length-zero-no-unit/index.js           | 6 ++++++
 2 files changed, 14 insertions(+)

diff --git a/lib/rules/length-zero-no-unit/__tests__/index.js b/lib/rules/length-zero-no-unit/__tests__/index.js
index 00718b22cd..d14d5def39 100644
--- a/lib/rules/length-zero-no-unit/__tests__/index.js
+++ b/lib/rules/length-zero-no-unit/__tests__/index.js
@@ -220,6 +220,14 @@ testRule({
 		{
 			code: 'a { lIne-hEight: 0px; }',
 		},
+		{
+			code: 'a { flex: 0px; }',
+			description: 'ignore flex property',
+		},
+		{
+			code: 'a { Flex: 0px; }',
+			description: 'ignore cased flex property',
+		},
 		{
 			code: 'a { grid-auto-columns: 0fr; }',
 			description: 'ignore some grid properties with `fr`',
diff --git a/lib/rules/length-zero-no-unit/index.js b/lib/rules/length-zero-no-unit/index.js
index 042b2ec5d0..5daf8e8eb2 100644
--- a/lib/rules/length-zero-no-unit/index.js
+++ b/lib/rules/length-zero-no-unit/index.js
@@ -107,6 +107,8 @@ function rule(primary, secondary, context) {
 
 			if (isLineHeight(prop)) return;
 
+			if (isFlex(prop)) return;
+
 			if (optionsMatches(secondary, 'ignore', 'custom-properties') && isCustomProperty(prop))
 				return;
 
@@ -142,6 +144,10 @@ function isLineHeight(prop) {
 	return prop.toLowerCase() === 'line-height';
 }
 
+function isFlex(prop) {
+	return prop.toLowerCase() === 'flex';
+}
+
 function isWord({ type }) {
 	return type === 'word';
 }