From d7e10e40ee82556e663e2fc2a64133a1b814ff9b Mon Sep 17 00:00:00 2001
From: "J. King" <jking@jkingweb.ca>
Date: Sat, 1 Feb 2020 23:43:46 -0500
Subject: [PATCH] Prefer PCOV for code coverage

---
 README.md    |  2 +-
 RoboFile.php | 39 ++++++++++++++++++++++++++-------------
 2 files changed, 27 insertions(+), 14 deletions(-)

diff --git a/README.md b/README.md
index 0658d785..f6932abe 100644
--- a/README.md
+++ b/README.md
@@ -88,7 +88,7 @@ There is also a `test:quick` Robo task which excludes slower tests, and a `test:
 
 ### Test coverage
 
-Computing the coverage of tests can be done by running `./robo coverage`, after which an HTML-format coverage report will be written to `/tests/coverage/`. Either [Xdebug](https://xdebug.org) or [phpdbg](https://php.net/manual/en/book.phpdbg.php) is required for this. Xdebug is generally recommended as it is better maintained, though phpdbg is significantly faster. If using Xdebug, the extension need not be enabled globally; PHPUnit will enable it when needed.
+Computing the coverage of tests can be done by running `./robo coverage`, after which an HTML-format coverage report will be written to `/tests/coverage/`. Either [PCOV](https://github.com/krakjoe/pcov), [Xdebug](https://xdebug.org), or [phpdbg](https://php.net/manual/en/book.phpdbg.php) is required for this. PCOV is generally recommended as it is faster than Xdebug; phpdbg is faster still, but less accurate. If using either PCOV or Xdebug, the extension need not be enabled globally; PHPUnit will enable it when needed.
 
 ## Enforcing coding style
 
diff --git a/RoboFile.php b/RoboFile.php
index f382090e..6a8472b6 100644
--- a/RoboFile.php
+++ b/RoboFile.php
@@ -53,9 +53,9 @@ class RoboFile extends \Robo\Tasks {
      * tests/coverage/. Additional reports may be produced by passing
      * arguments to this task as one would to PHPUnit.
      *
-     * Robo first tries to use phpdbg and will fall back to Xdebug if available.
-     * Because Xdebug slows down non-coverage tasks, however, phpdbg is highly
-     * recommended if debugging facilities are not otherwise needed.
+     * Robo first tries to use pcov and will fall back first to xdebug then
+     * phpdbg. Neither pcov nor xdebug need to be enabled to be used; they 
+     * only need to be present in the extension load path to be used.
     */
     public function coverage(array $args): Result {
         // run tests with code coverage reporting enabled
@@ -89,17 +89,30 @@ class RoboFile extends \Robo\Tasks {
     }
 
     protected function findCoverageEngine(): string {
-        if (IS_WIN) {
-            $dbg = dirname(\PHP_BINARY)."\\phpdbg.exe";
-            $dbg = file_exists($dbg) ? $dbg : "";
+        $dir = rtrim(ini_get("extension_dir"), "/").\DIRECTORY_SEPARATOR;
+        $ext = IS_WIN ? "dll" : (IS_MAC ? "dylib" : "so");
+        $php = escapeshellarg(\PHP_BINARY);
+        $code = escapeshellarg(BASE."lib");
+        if (extension_loaded("pcov")) {
+            return "$php -d pcov.enabled=1 -d pcov.directory=$code";
+        } elseif (extension_loaded("xdebug")) {
+            return $php;
+        } elseif (file_exists($dir."pcov.$ext")) {
+            return "$php -d extension=pcov.$ext -d pcov.enabled=1 -d pcov.directory=$code";
+        } elseif (file_exists($dir."pcov.$ext")) {
+            return "$php -d zend_extension=xdebug.$ext";
         } else {
-            $dbg = trim(`which phpdbg 2>/dev/null`);
-        }
-        if ($dbg) {
-            return escapeshellarg($dbg)." -qrr";
-        } else {
-            $ext = IS_WIN ? "dll" : (IS_MAC ? "dylib" : "so");
-            return escapeshellarg(\PHP_BINARY)." -d zend_extension=xdebug.$ext";
+            if (IS_WIN) {
+                $dbg = dirname(\PHP_BINARY)."\\phpdbg.exe";
+                $dbg = file_exists($dbg) ? $dbg : "";
+            } else {
+                $dbg = trim(`which phpdbg 2>/dev/null`);
+            }
+            if ($dbg) {
+                return escapeshellarg($dbg)." -qrr";
+            } else {
+                return $php;
+            }
         }
     }