add anchors when constructing pattern from a non-regex oldline

_test/tests/inc/io_replaceinfile.test.php

@@ -79,4 +79,17 @@ function test_edgecase2() {
         $this->assertTrue(io_replaceInFile($file, "Delete\012", "Delete\012", false, -1));
         $this->assertEquals("The\012Delete\012Delete\012Delete01\012Delete02\012Delete\012DeleteX\012Test\012", io_readFile($file), "Edge case: new line the same as old line");
     }
+
+    /**
+     *
+     */
+    function test_edgecase3()
+    {
+        $file = TMP_DIR . '/test.txt';
+        $contents = "The\012Delete\01201Delete\01202Delete\012Test\012";
+        // Replace all, no regex, oldline exactly matches one line; matches part of other lines - only the exact match should be replaced
+        io_saveFile($file, $contents);
+        $this->assertTrue(io_replaceInFile($file, "Delete\012", "Replace\012", false, -1));
+        $this->assertEquals("The\012Replace\01201Delete\01202Delete\012Test\012", io_readFile($file), "Edge case: old line is a match for parts of other lines");
+    }
 }

inc/io.php

@@ -312,7 +312,7 @@ function io_replaceInFile($file, $oldline, $newline, $regex=false, $maxlines=0)
     }
 
     // make non-regexes into regexes
-    $pattern = $regex ? $oldline : '/'.preg_quote($oldline,'/').'/';
+    $pattern = $regex ? $oldline : '/^'.preg_quote($oldline,'/').'$/';
     $replace = $regex ? $newline : addcslashes($newline, '\$');
 
     // remove matching lines