From 4a26aebe752764d7a84859a5124c1e88e05d6432 Mon Sep 17 00:00:00 2001
From: Andrew Nicols <andrew@nicols.co.uk>
Date: Fri, 6 Nov 2020 16:14:56 +0800
Subject: [PATCH 1/1] DONOTCOMMIT: 70137 post-patch testing

---
 cache/classes/config.php |  7 +++++++
 cache/locallib.php       | 13 +++++++++++++
 2 files changed, 20 insertions(+)

diff --git a/cache/classes/config.php b/cache/classes/config.php
index 021e2a69dd9..fee874e2e16 100644
--- a/cache/classes/config.php
+++ b/cache/classes/config.php
@@ -331,9 +331,16 @@ class cache_config {
             throw new cache_exception('Default cache config could not be found. It should have already been created by now.');
         }
 
+        error_log(getmypid() . ": About to include {$cachefile}.");
         if (!include($cachefile)) {
             throw new cache_exception('Unable to load the cache configuration file');
         }
+        error_log(getmypid() . ": Finished including {$cachefile}.");
+        if (is_array($configuration)) {
+           error_log(getmypid() . ": It has a size of " . count($configuration));
+        } else {
+           error_log(getmypid() . ": It has a size of 0");
+        }
 
         if (!is_array($configuration)) {
             throw new cache_exception('Invalid cache configuration file');
diff --git a/cache/locallib.php b/cache/locallib.php
index db20b05fb2f..e5401b2c477 100644
--- a/cache/locallib.php
+++ b/cache/locallib.php
@@ -86,6 +86,10 @@ class cache_config_writer extends cache_config {
         // Prepare the file content.
         $content = "<?php defined('MOODLE_INTERNAL') || die();\n \$configuration = ".var_export($configuration, true).";";
 
+        error_log(getmypid() . ": About to write the MUC config. Sleeping for a few seconds first.");
+        sleep(5);
+        error_log(getmypid() . ": Done sleeping - writing!");
+
         // We need to create a temporary cache lock instance for use here. Remember we are generating the config file
         // it doesn't exist and thus we can't use the normal API for this (it'll just try to use config).
         $lockconf = reset($this->configlocks);
@@ -105,6 +109,14 @@ class cache_config_writer extends cache_config {
             $tempcachefile = "{$cachefile}.tmp";
             // Its safe to use w mode here because we have already acquired the lock.
             $handle = fopen($tempcachefile, 'w');
+
+        error_log(getmypid() . ": Obtained file lock and handle. Pausing for a few seconds.");
+        error_log("========");
+        error_log("LOAD THE OTHER BROWSER TAB NOW!!!");
+        error_log("========");
+        sleep(3);
+        error_log(getmypid() . ": Done sleeping - writing!");
+
             fwrite($handle, $content);
             fflush($handle);
             fclose($handle);
@@ -116,6 +128,7 @@ class cache_config_writer extends cache_config {
         } else {
             throw new cache_exception('ex_configcannotsave', 'cache', '', null, 'Unable to open the cache config file.');
         }
+        die;
     }
 
     /**
-- 
2.26.2