php not working within apache2

After updating from ubuntu 16.04 to 18.04 I noticed that php-curl was not working, but php was working fine. I thought the problem was that apache2 was still using php7.0 instead of php7.2, so I ran

sudo a2dismod php7.0
sudo a2enmod php7.2
sudo systemctl restart apache2

now php doesn't work, but html code is rendered...

this returns a blank page:

<?php phpinfo(); ?> 

I double-checked my implementation of phpinfo() using the version found in the php:phpinfo -manual page, repeated below, still doesn't work with apache, but it does work when I run within bash the following

my-machine:~$ php public_html/info.php

Here is an edited version of http://php.net/manual/en/function.phpinfo.php

<?php    
phpinfo();
// Show just the module information.
// phpinfo(8) yields identical results.
phpinfo(INFO_MODULES);
?>

I also tried

sudo update-alternatives --set php /usr/bin/php7.2

I've edited /etc/php/7.2/apache2/php.ini as directed in one page as follows:

short_open_tag = On

Here is some info about my setup.

php version

php -v
PHP 7.2.7-0ubuntu0.18.04.2 (cli) (built: Jul  4 2018 16:55:24) ( NTS )
Copyright (c) 1997-2018 The PHP Group
Zend Engine v3.2.0, Copyright (c) 1998-2018 Zend Technologies
    with Zend OPcache v7.2.7-0ubuntu0.18.04.2, Copyright (c) 1999-2018, by Zend Technologies

a2query

a2query -m php7.2
php7.2 (enabled by site administrator)

list of apache2 modules, note: "AH01574: module php7_module is already loaded, skipping" is occurring because I also ran =sudo a2enmod php7.0= hoping to go back to what I thought I had... I did disable php7.2 and enable php7.0 and restart apache2 with sudo systemctl restart apache2, but php is not being rendered.

apache2ctl -M
[Sun Sep 02 18:03:43.185183 2018] [so:warn] [pid 4166] AH01574: module php7_module is already loaded, skipping
AH00558: apache2: Could not reliably determine the server's fully qualified domain name, using 127.0.1.1. Set the 'ServerName' directive globally to suppress this message
Loaded Modules:
 core_module (static)
 so_module (static)
 watchdog_module (static)
 http_module (static)
 log_config_module (static)
 logio_module (static)
 version_module (static)
 unixd_module (static)
 access_compat_module (shared)
 alias_module (shared)
 auth_basic_module (shared)
 authn_core_module (shared)
 authn_file_module (shared)
 authz_core_module (shared)
 authz_host_module (shared)
 authz_user_module (shared)
 autoindex_module (shared)
 deflate_module (shared)
 dir_module (shared)
 dnssd_module (shared)
 env_module (shared)
 filter_module (shared)
 mime_module (shared)
 mpm_prefork_module (shared)
 negotiation_module (shared)
 php7_module (shared)
 reqtimeout_module (shared)
 setenvif_module (shared)
 status_module (shared)
 userdir_module (shared)

list of php packages installed

sudo apt list --installed | grep -i php

WARNING: apt does not have a stable CLI interface. Use with caution in scripts.

libapache2-mod-php/bionic,bionic,now 1:7.2+60ubuntu1 all [installed]
libapache2-mod-php7.0/now 7.0.30-0ubuntu0.16.04.1 amd64 [installed,local]
libapache2-mod-php7.2/bionic-updates,bionic-security,now 7.2.7-0ubuntu0.18.04.2 amd64 [installed]
libphp-phpmailer/bionic,bionic,now 5.2.14+dfsg-2.3 all [installed,automatic]
php/bionic,bionic,now 1:7.2+60ubuntu1 all [installed]
php-bz2/bionic,bionic,now 1:7.2+60ubuntu1 all [installed,automatic]
php-cli/bionic,bionic,now 1:7.2+60ubuntu1 all [installed,automatic]
php-common/bionic,bionic,now 1:60ubuntu1 all [installed]
php-curl/bionic,bionic,now 1:7.2+60ubuntu1 all [installed]
php-db/bionic,bionic,now 1.9.2-2ubuntu1 all [installed]
php-gd/bionic,bionic,now 1:7.2+60ubuntu1 all [installed,automatic]
php-getid3/bionic,bionic,now 1.9.15+dfsg-1 all [installed,automatic]
php-gettext/bionic,bionic,now 1.0.12-0.1 all [installed,automatic]
php-mbstring/bionic,bionic,now 1:7.2+60ubuntu1 all [installed,automatic]
php-mcrypt/now 1:7.0+35ubuntu6.1 all [installed,local]
php-mysql/bionic,bionic,now 1:7.2+60ubuntu1 all [installed]
php-pear/bionic,bionic,now 1:1.10.5+submodules+notgz-1ubuntu1 all [installed]
php-php-gettext/bionic,bionic,now 1.0.12-0.1 all [installed,automatic]
php-phpseclib/bionic,bionic,now 2.0.9-1 all [installed,automatic]
php-tcpdf/bionic,bionic,now 6.2.13+dfsg-1ubuntu1 all [installed,automatic]
php-tidy/bionic,bionic,now 1:7.2+60ubuntu1 all [installed]
php-xml/bionic,bionic,now 1:7.2+60ubuntu1 all [installed,automatic]
php-zip/bionic,bionic,now 1:7.2+60ubuntu1 all [installed,automatic]
php5-common/now 5.5.9+dfsg-1ubuntu4.19 amd64 [installed,local]
php5-json/now 1.3.2-2build1 amd64 [installed,local]
php5-mysql/now 5.5.9+dfsg-1ubuntu4.19 amd64 [installed,local]
php7.0/now 7.0.30-0ubuntu0.16.04.1 all [installed,local]
php7.0-cli/now 7.0.30-0ubuntu0.16.04.1 amd64 [installed,local]
php7.0-common/now 7.0.30-0ubuntu0.16.04.1 amd64 [installed,local]
php7.0-gd/now 7.0.30-0ubuntu0.16.04.1 amd64 [installed,local]
php7.0-json/now 7.0.30-0ubuntu0.16.04.1 amd64 [installed,local]
php7.0-mbstring/now 7.0.30-0ubuntu0.16.04.1 amd64 [installed,local]
php7.0-mcrypt/now 7.0.30-0ubuntu0.16.04.1 amd64 [installed,local]
php7.0-mysql/now 7.0.30-0ubuntu0.16.04.1 amd64 [installed,local]
php7.0-opcache/now 7.0.30-0ubuntu0.16.04.1 amd64 [installed,local]
php7.0-readline/now 7.0.30-0ubuntu0.16.04.1 amd64 [installed,local]
php7.0-xml/now 7.0.30-0ubuntu0.16.04.1 amd64 [installed,local]
php7.2/bionic-updates,bionic-updates,bionic-security,bionic-security,now 7.2.7-0ubuntu0.18.04.2 all [installed,automatic]
php7.2-bz2/bionic-updates,bionic-security,now 7.2.7-0ubuntu0.18.04.2 amd64 [installed,automatic]
php7.2-cli/bionic-updates,bionic-security,now 7.2.7-0ubuntu0.18.04.2 amd64 [installed,automatic]
php7.2-common/bionic-updates,bionic-security,now 7.2.7-0ubuntu0.18.04.2 amd64 [installed,automatic]
php7.2-curl/bionic-updates,bionic-security,now 7.2.7-0ubuntu0.18.04.2 amd64 [installed]
php7.2-gd/bionic-updates,bionic-security,now 7.2.7-0ubuntu0.18.04.2 amd64 [installed,automatic]
php7.2-json/bionic-updates,bionic-security,now 7.2.7-0ubuntu0.18.04.2 amd64 [installed,automatic]
php7.2-mbstring/bionic-updates,bionic-security,now 7.2.7-0ubuntu0.18.04.2 amd64 [installed,automatic]
php7.2-mysql/bionic-updates,bionic-security,now 7.2.7-0ubuntu0.18.04.2 amd64 [installed,automatic]
php7.2-opcache/bionic-updates,bionic-security,now 7.2.7-0ubuntu0.18.04.2 amd64 [installed,automatic]
php7.2-readline/bionic-updates,bionic-security,now 7.2.7-0ubuntu0.18.04.2 amd64 [installed,automatic]
php7.2-tidy/bionic-updates,bionic-security,now 7.2.7-0ubuntu0.18.04.2 amd64 [installed,automatic]
php7.2-xml/bionic-updates,bionic-security,now 7.2.7-0ubuntu0.18.04.2 amd64 [installed,automatic]
php7.2-zip/bionic-updates,bionic-security,now 7.2.7-0ubuntu0.18.04.2 amd64 [installed,automatic]
phpmyadmin/bionic,bionic,now 4:4.6.6-5 all [installed]

apt policy libapache2-mod-php7.2

sudo apt policy libapache2-mod-php7.2
libapache2-mod-php7.2:
  Installed: 7.2.7-0ubuntu0.18.04.2
  Candidate: 7.2.7-0ubuntu0.18.04.2
  Version table:
 *** 7.2.7-0ubuntu0.18.04.2 500
        500 http://us.archive.ubuntu.com/ubuntu bionic-updates/main amd64 Packages
        500 http://security.ubuntu.com/ubuntu bionic-security/main amd64 Packages
        100 /var/lib/dpkg/status
     7.2.3-1ubuntu1 500
        500 http://us.archive.ubuntu.com/ubuntu bionic/main amd64 Packages

ls -l /etc/apache2/mods-enabled/php*

ls -l /etc/apache2/mods-enabled/php*
lrwxrwxrwx 1 root root 29 Sep  2 18:48 /etc/apache2/mods-enabled/php7.2.conf -> ../mods-available/php7.2.conf
lrwxrwxrwx 1 root root 29 Sep  2 18:48 /etc/apache2/mods-enabled/php7.2.load -> ../mods-available/php7.2.load

sample of apache2 logs

[Mon Sep 03 00:06:52.805155 2018] [mpm_prefork:notice] [pid 5161] AH00163: Apache/2.4.29 (Ubuntu) configured -- resuming normal operations
[Mon Sep 03 00:06:52.805181 2018] [core:notice] [pid 5161] AH00094: Command line: '/usr/sbin/apache2'
[Sun Sep 02 13:39:30.728738 2018] [:error] [pid 4109] [client 127.0.0.1:36468] PHP Notice:  Only variables should be assigned by reference in /home/go/public_html/index.php on line 115
[Sun Sep 02 13:39:30.739232 2018] [:error] [pid 4109] [client 127.0.0.1:36468] PHP Notice:  Undefined variable: year in /home/go/public_html/calendar.php on line 38
[Sun Sep 02 13:39:30.739253 2018] [:error] [pid 4109] [client 127.0.0.1:36468] PHP Notice:  Undefined variable: month in /home/go/public_html/calendar.php on line 40
[Sun Sep 02 13:39:30.739256 2018] [:error] [pid 4109] [client 127.0.0.1:36468] PHP Notice:  Undefined variable: year in /home/go/public_html/calendar.php on line 42
[Sun Sep 02 13:39:30.739260 2018] [:error] [pid 4109] [client 127.0.0.1:36468] PHP Notice:  Undefined variable: year in /home/go/public_html/calendar.php on line 46
[Sun Sep 02 13:39:30.739278 2018] [:error] [pid 4109] [client 127.0.0.1:36468] PHP Notice:  Undefined variable: month in /home/go/public_html/calendar.php on line 52
[Sun Sep 02 13:39:30.739281 2018] [:error] [pid 4109] [client 127.0.0.1:36468] PHP Notice:  Undefined variable: month in /home/go/public_html/calendar.php on line 56
[Sun Sep 02 13:39:35.889200 2018] [:error] [pid 4111] [client 127.0.0.1:36478] PHP Notice:  Only variables should be assigned by reference in /home/go/public_html/show-reading-list.php on line 7, referer: http://localhost/~go/

variables mentioned in logs are in these php files... and I see the same errors in previous logs generated before the update.


php and php-curl are now working.

What led me to the answer is noticing a difference between php7.0.conf and php7.2.conf in /etc/apache2/mods-available/, that would only affect how php performed within the userdir. I then checked whether php worked at the server and saw that it did.

In summary, I believe that after the update from ubuntu 16.04 and 18.04 I needed to

  • disable php7.0 and enable php7.2: this created a problem with the user directory php scripts, but did fix the php-curl under the server. In other words, at this point php an php-curl was functioning at the server address;
  • edit the php7.2.conf file and comment out the <IfModule mod_userdir.c> section;
  • for those reading the entire question, I did not keep the edit to the php.ini file;
  • cleared the cache from firefox: the change did not fix the userdir problem until I did the following: open menu->preferences->privacy and security->history->use custom settings for history->clear history->settings->history->cache (all other boxes unchecked)

php and php-curl now working in userdir.

Thanks to everyone who left a comment.