diff --git a/src/ChangeEnumerator.php b/src/ChangeEnumerator.php
index 0f468b3e..b3c4c555 100644
--- a/src/ChangeEnumerator.php
+++ b/src/ChangeEnumerator.php
@@ -207,11 +207,8 @@ public function find(string $contents): string
             function ($matches) {
 
                 // If we're inside a namespace other than the global namespace:
-                if (1 === preg_match('/\s*namespace\s+[a-zA-Z0-9_\x7f-\xff\\\\]+[;{\s\n]{1}.*/', $matches[0])) {
-
-                    if(isset($matches[1])) {
-                        $this->addDiscoveredNamespaceChange($matches[1]);
-                    }
+                if (1 === preg_match('/^\s*namespace\s+[a-zA-Z0-9_\x7f-\xff\\\\]+[;{\s\n]{1}.*/', $matches[0])) {
+                    $this->addDiscoveredNamespaceChange($matches[1]);
 
                     return $matches[0];
                 }
diff --git a/tests/Issues/StraussIssue91Test.php b/tests/Issues/StraussIssue91Test.php
new file mode 100644
index 00000000..87a96080
--- /dev/null
+++ b/tests/Issues/StraussIssue91Test.php
@@ -0,0 +1,52 @@
+<?php
+/**
+ * Undefined offset: 1
+ *
+ * @see https://github.com/BrianHenryIE/strauss/pull/91
+ */
+
+namespace BrianHenryIE\Strauss\Tests\Issues;
+
+use BrianHenryIE\Strauss\Console\Commands\Compose;
+use BrianHenryIE\Strauss\Tests\Integration\Util\IntegrationTestCase;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Output\OutputInterface;
+
+/**
+ * @package BrianHenryIE\Strauss\Tests\Issues
+ * @coversNothing
+ */
+class StraussIssue91Test extends IntegrationTestCase
+{
+    public function test_namespace_keyword_on_opening_line()
+    {
+        $composerJsonString = <<<'EOD'
+{
+  "name": "pr/91",
+  "require": {
+    "phpoffice/phpspreadsheet": "1.29"
+  },
+  "extra": {
+    "strauss": {
+      "namespace_prefix": "Company\\Project\\"
+    }
+  }
+}
+EOD;
+
+        chdir($this->testsWorkingDir);
+
+        file_put_contents($this->testsWorkingDir . '/composer.json', $composerJsonString);
+
+        exec('composer install');
+
+        $inputInterfaceMock = $this->createMock(InputInterface::class);
+        $outputInterfaceMock = $this->createMock(OutputInterface::class);
+
+        $strauss = new Compose();
+
+        $result = $strauss->run($inputInterfaceMock, $outputInterfaceMock);
+
+        self::assertEquals(0, $result);
+    }
+}
diff --git a/tests/Unit/ChangeEnumeratorTest.php b/tests/Unit/ChangeEnumeratorTest.php
index cfbfba52..c640d66e 100644
--- a/tests/Unit/ChangeEnumeratorTest.php
+++ b/tests/Unit/ChangeEnumeratorTest.php
@@ -120,6 +120,50 @@ class MyOtherClass {
         self::assertNotContains('MyOtherClass', $sut->getDiscoveredClasses());
     }
 
+    public function testItDoesNotFindNamespaceInComment(): void
+    {
+
+        $validPhp = <<<'EOD'
+<?php
+
+/**
+ * @todo Rewrite to use Interchange objects
+ */
+class HTMLPurifier_Printer_ConfigForm extends HTMLPurifier_Printer
+{
+
+    /**
+     * Returns HTML output for a configuration form
+     * @param HTMLPurifier_Config|array $config Configuration object of current form state, or an array
+     *        where [0] has an HTML namespace and [1] is being rendered.
+     * @param array|bool $allowed Optional namespace(s) and directives to restrict form to.
+     * @param bool $render_controls
+     * @return string
+     */
+    public function render($config, $allowed = true, $render_controls = true)
+    {
+
+        // blah
+
+        return $ret;
+    }
+
+}
+
+// vim: et sw=4 sts=4
+EOD;
+
+        $config = $this->createMock(StraussConfig::class);
+        $sut = new ChangeEnumerator($config);
+
+        try {
+            $sut->find($validPhp);
+        } catch (\PHPUnit\Framework\Error\Warning $e) {
+            self::fail('Should not throw an exception');
+        }
+
+        self::assertEmpty($sut->getDiscoveredNamespaces());
+    }
 
     /**
      *