From b96acf6d5a22c833c05098256b9da5e5bf1dbf24 Mon Sep 17 00:00:00 2001
From: ignace namagana butera <nyamsprod@gmail.com>
Date: Sat, 29 Feb 2020 20:42:23 +0100
Subject: [PATCH] Improve PR #161

---
 CHANGELOG.md        | 18 ++++++++++++++++++
 src/UriTemplate.php | 11 +++++++----
 2 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index e8ffcb19..323d2af3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,24 @@
 
 All Notable changes to `League\Uri` will be documented in this file
 
+## Next - TBD
+
+### Added 
+
+- None
+
+### Fixed
+
+- Bugfix `UriTemplate::expand` to comply with expansion rules for undefined variables [#161](https://github.com/thephpleague/uri/pull/161) thanks [Gabe Sullice](https://github.com/gabesullice)
+
+### Deprecated
+
+- Nothing
+
+### Remove
+
+- Hard dependencies on the `ext-mbstring` and the `ext-fileinfo` PHP extensions [#154](https://github.com/thephpleague/uri/pull/154) thanks [Nicolas Grekas](https://github.com/nicolas-grekas)
+
 ## 6.2.0 - 2020-02-08
 
 ### Added 
diff --git a/src/UriTemplate.php b/src/UriTemplate.php
index 248d2272..639e18bb 100644
--- a/src/UriTemplate.php
+++ b/src/UriTemplate.php
@@ -18,6 +18,7 @@
 use League\Uri\Exceptions\SyntaxError;
 use League\Uri\Exceptions\TemplateCanNotBeExpanded;
 use function array_filter;
+use function array_key_exists;
 use function array_keys;
 use function explode;
 use function gettype;
@@ -402,9 +403,7 @@ private function expandExpression(array $foundExpression): string
         $parts = [];
         /** @var array{name:string, modifier:string, position:string} $variable */
         foreach ($expression['variables'] as $variable) {
-            if (isset($this->variables[$variable['name']])) {
-                $parts[] = $this->expandVariable($variable, $expression['operator'], $joiner, $useQuery);
-            }
+            $parts[] = $this->expandVariable($variable, $expression['operator'], $joiner, $useQuery);
         }
 
         $nullFilter = static function ($value): bool {
@@ -430,7 +429,11 @@ private function expandExpression(array $foundExpression): string
      */
     private function expandVariable(array $variable, string $operator, string $joiner, bool $useQuery): string
     {
-        $value = $this->variables[$variable['name']] ?? '';
+        if (!array_key_exists($variable['name'], $this->variables)) {
+            return '';
+        }
+
+        $value = $this->variables[$variable['name']];
         $arguments = [$value, $variable, $operator];
         $method = 'expandString';
         if (is_array($value)) {