From e386a6004d15971e977da150edf574fde03237ac Mon Sep 17 00:00:00 2001
From: ignace nyamagana butera <nyamsprod@gmail.com>
Date: Wed, 12 Aug 2020 17:43:33 +0200
Subject: [PATCH] bug fix issue #171

---
 CHANGELOG.md      | 1 +
 composer.json     | 2 +-
 src/Uri.php       | 6 +++---
 src/UriString.php | 2 +-
 tests/UriTest.php | 8 ++++++++
 5 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index d19dc0b1..55c02b27 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -14,6 +14,7 @@ imporove `UriTemplate` implementation.
 
 - `UriTemplate` complete rewrite by reducing deep nested array usage.
 - Exception misleading message see issue [#167](https://github.com/thephpleague/uri/issues/167)
+- `Uri::withScheme` Uri validation failed to catch the empty string as an invalid scheme.
 
 ### Deprecated
 
diff --git a/composer.json b/composer.json
index 2a30c17e..b0d95691 100644
--- a/composer.json
+++ b/composer.json
@@ -44,7 +44,7 @@
         }
     ],
     "require": {
-        "php": "^7.2",
+        "php": ">=7.2",
         "ext-json": "*",
         "psr/http-message": "^1.0",
         "league/uri-interfaces": "^2.1"
diff --git a/src/Uri.php b/src/Uri.php
index f8f6074b..19067fb0 100644
--- a/src/Uri.php
+++ b/src/Uri.php
@@ -310,7 +310,7 @@ private function __construct(
      */
     private function formatScheme(?string $scheme): ?string
     {
-        if ('' === $scheme || null === $scheme) {
+        if (null === $scheme) {
             return $scheme;
         }
 
@@ -319,7 +319,7 @@ private function formatScheme(?string $scheme): ?string
             return $formatted_scheme;
         }
 
-        throw new SyntaxError(sprintf('The scheme `%s` is invalid', $scheme));
+        throw new SyntaxError(sprintf('The scheme `%s` is invalid.', $scheme));
     }
 
     /**
@@ -438,7 +438,7 @@ private function formatRegisteredName(string $host): string
             $arr
         );
 
-        if ($arr === []) {
+        if ([] === $arr) {
             throw new SyntaxError(sprintf('Host `%s` is invalid', $host));
         }
 
diff --git a/src/UriString.php b/src/UriString.php
index 6e0987f0..7010cac8 100644
--- a/src/UriString.php
+++ b/src/UriString.php
@@ -472,7 +472,7 @@ private static function filterRegisteredName(string $host): string
 
         $retval = idn_to_ascii($formatted_host, 0, INTL_IDNA_VARIANT_UTS46, $arr);
 
-        if ($arr === []) {
+        if ([] === $arr) {
             throw new SyntaxError(sprintf('Host `%s` is not a valid IDN host', $host));
         }
 
diff --git a/tests/UriTest.php b/tests/UriTest.php
index ffdef355..19a6ef6b 100644
--- a/tests/UriTest.php
+++ b/tests/UriTest.php
@@ -580,4 +580,12 @@ public function testIssue167ExceptionReasonMisleadingMessage(): void
 
         Uri::createFromString('file://example.org:80/home/jsmith/foo.txt');
     }
+
+    public function testIssue171TheEmptySchemeShouldThrow(): void
+    {
+        self::expectException(SyntaxError::class);
+        self::expectExceptionMessage('The scheme `` is invalid.');
+
+        Uri::createFromString('domain.com')->withScheme('');
+    }
 }