From bb4fef2bf035a50170fd95e5b146152834126008 Mon Sep 17 00:00:00 2001
From: Christian Flothmann <christian.flothmann@qossmic.com>
Date: Mon, 16 Sep 2024 09:16:29 +0200
Subject: [PATCH] throw a meaningful exception when parsing dotenv files with
 BOM

---
 Dotenv.php                   |  8 +++++++-
 Tests/DotenvTest.php         | 10 ++++++++++
 Tests/fixtures/file_with_bom |  1 +
 3 files changed, 18 insertions(+), 1 deletion(-)
 create mode 100644 Tests/fixtures/file_with_bom

diff --git a/Dotenv.php b/Dotenv.php
index b454452..d164aa0 100644
--- a/Dotenv.php
+++ b/Dotenv.php
@@ -568,7 +568,13 @@ private function doLoad(bool $overrideExistingVars, array $paths): void
                 throw new PathException($path);
             }
 
-            $this->populate($this->parse(file_get_contents($path), $path), $overrideExistingVars);
+            $data = file_get_contents($path);
+
+            if ("\xEF\xBB\xBF" === substr($data, 0, 3)) {
+                throw new FormatException('Loading files starting with a byte-order-mark (BOM) is not supported.', new FormatExceptionContext($data, $path, 1, 0));
+            }
+
+            $this->populate($this->parse($data, $path), $overrideExistingVars);
         }
     }
 }
diff --git a/Tests/DotenvTest.php b/Tests/DotenvTest.php
index 644126d..8ba0230 100644
--- a/Tests/DotenvTest.php
+++ b/Tests/DotenvTest.php
@@ -604,4 +604,14 @@ public function testBootEnv()
         $resetContext();
         rmdir($tmpdir);
     }
+
+    public function testExceptionWithBom()
+    {
+        $dotenv = new Dotenv();
+
+        $this->expectException(FormatException::class);
+        $this->expectExceptionMessage('Loading files starting with a byte-order-mark (BOM) is not supported.');
+
+        $dotenv->load(__DIR__.'/fixtures/file_with_bom');
+    }
 }
diff --git a/Tests/fixtures/file_with_bom b/Tests/fixtures/file_with_bom
new file mode 100644
index 0000000..242249b
--- /dev/null
+++ b/Tests/fixtures/file_with_bom
@@ -0,0 +1 @@
+FOO=BAR