If one analysis of the file is based on executed code, and one is based only on reviewing the unexecuted code, accept the one from execution automatically as it will have the most accurate list of executable lines, and prevents incorrect stats following a merge where a file was executed in one run, but not executed in another

Author: iainfogg

src/CodeCoverage.php

@@ -357,6 +357,35 @@ public function merge(PHP_CodeCoverage $that)
                 continue;
             }
 
+            // Check if there are some lines already present in the two
+            // versions being merged, and also that the number of lines
+            // in each is different. This indicates that one is based on
+            // pulling lines in from glancing through the code in unexecuted
+            // code (the one with more lines in), and one is based on using Xdebug
+            // to properly analyse the code (the one with less lines in).
+            // In this scenario, ditch the lines from the unexecuted analysis,
+            // as it will contain lines which are not classed as executable by
+            // Xdebug, and those lines will throw the code analysis by appearing
+            // as if they should be run but weren't.
+            if ((count($lines) > 0)
+                && (count($this->data[$file]) > 0)
+                && (count($lines) != count($this->data[$file]))
+            ) {
+                if (count($lines) > count($this->data[$file])) {
+                    // More lines in the one being added in, so just ignore them
+                    // and move on to the next file.
+                    continue;
+                } else {
+                    // More lines in the one we currently have, so ditch what we
+                    // currently have and take what's being merged in exactly as
+                    // it is.
+                    $this->data[$file] = $lines;
+
+                    // Move on to the next file.
+                    continue;
+                }
+            }
+            
             foreach ($lines as $line => $data) {
                 if ($data !== null) {
                     if (!isset($this->data[$file][$line])) {