[Bug]: IMigrationStep progress bar does not advance(), error found in ConsoleOutput.php

[birnbacs]

⚠️ This issue respects the following points: ⚠️

• This is a bug, not a question or a configuration/webserver/proxy issue.
• This issue is not already reported on Github (I've searched it).
• Nextcloud Server is up to date. See Maintenance and Release Schedule for supported versions.
• Nextcloud Server is running on 64bit capable CPU, PHP and OS.
• I agree to follow Nextcloud's Code of Conduct.

Bug description

Nextcloud's migration system supports Repair Steps for db maintenance.
IMigrationStep offers a progress bar for console output.
The progress bar is a Symfony\Component\Console\Helper\ProgressBar component.

The progress bar does not advance when the advance() method is called.
Displayed is a series of empty bars and one final full bar.

Here is the cause:

In nextcloud/server/lib/private/Migration/ConsoleOutput.php #78 (function advance()) the call to the symfony object is wrong. The line reads:
if (!is_null($this->progressBar)) {
but it should read:
if (is_null($this->progressBar)) {
(note the missing negation)

Two more things: the second argument to NC's advance() method is not output at all and no newline character is appended to the output so the progress bars are all in the same line.

Steps to reproduce

1. create class MyRepairStep: https://docs.nextcloud.com/server/19/developer_manual/app/repair.html?highlight=advance
2. create schema file '000001Date20220303134500' that calls the created MyRepairStep in PostSchemaChange()
3. trigger the migration manually: sudo -u www occ migrations:execute MyApp 000001Date20220303134500

Expected behavior

output should read roughly like this:
This step will take 10 seconds. 0/10 [>---------------------------] 1/10 [->--------------------------] 2/10 [-->-------------------------] 3/10 [--->------------------------] 4/10 [---->-----------------------] 5/10 [----->----------------------] 6/10 [------>---------------------] 7/10 [------->--------------------] 8/10 [-------->-------------------] 9/10 [--------->------------------] 1 [============================]

Installation method

Community Manual installation with Archive

Operating system

Other

PHP engine version

PHP 8.1

Web server

Nginx

Database engine version

PostgreSQL

Is this bug present after an update or on a fresh install?

Fresh Nextcloud Server install

Are you using the Nextcloud Server Encryption module?

Encryption is Disabled

What user-backends are you using?

• Default user-backend (database)
• LDAP/ Active Directory
• SSO - SAML
• Other

Configuration report

{
    "system": {
        "defaultapp": "abakus,files",
        "default_language": "de",
        "debug": true,
        "apps_paths": [
            {
                "path": "\/usr\/local\/www\/nextcloud\/apps",
                "url": "\/apps",
                "writable": true
            },
            {
                "path": "\/usr\/local\/www\/nextcloud\/apps-pkg",
                "url": "\/apps-pkg",
                "writable": false
            }
        ],
        "logfile": "\/var\/log\/nextcloud\/nextcloud.log",
        "memcache.local": "\\OC\\Memcache\\APCu",
        "instanceid": "***REMOVED SENSITIVE VALUE***",
        "passwordsalt": "***REMOVED SENSITIVE VALUE***",
        "secret": "***REMOVED SENSITIVE VALUE***",
        "trusted_domains": [
            "192.168.245.51",
            "devcloud.here.us",
            "devcloud01.here.us"
        ],
        "datadirectory": "***REMOVED SENSITIVE VALUE***",
        "dbtype": "pgsql",
        "version": "25.0.0.18",
        "overwrite.cli.url": "https:\/\/devcloud01.here.us",
        "dbname": "***REMOVED SENSITIVE VALUE***",
        "dbhost": "***REMOVED SENSITIVE VALUE***",
        "dbport": "",
        "dbtableprefix": "oc_",
        "dbuser": "***REMOVED SENSITIVE VALUE***",
        "dbpassword": "***REMOVED SENSITIVE VALUE***",
        "installed": true,
        "app_install_overwrite": [
            "notestutorial",
            "apporder"
        ],
        "maintenance": false,
        "theme": "",
        "loglevel": 2
    }
}

List of activated Apps

Enabled:
  - abakus: 0.2.1
  - circles: 25.0.0
  - cloud_federation_api: 1.8.0
  - comments: 1.15.0
  - contactsinteraction: 1.6.0
  - dav: 1.24.0
  - federatedfilesharing: 1.15.0
  - federation: 1.15.0
  - files: 1.20.1
  - files_pdfviewer: 2.6.0
  - files_rightclick: 1.4.0
  - files_sharing: 1.17.0
  - files_trashbin: 1.15.0
  - files_versions: 1.18.0
  - firstrunwizard: 2.14.0
  - logreader: 2.10.0
  - lookup_server_connector: 1.13.0
  - nextcloud_announcements: 1.14.0
  - notestutorial: 18.0.0
  - notifications: 2.13.1
  - oauth2: 1.13.0
  - password_policy: 1.15.0
  - privacy: 1.9.0
  - provisioning_api: 1.15.0
  - recommendations: 1.4.0
  - related_resources: 1.0.3
  - serverinfo: 1.15.0
  - settings: 1.7.0
  - sharebymail: 1.15.0
  - support: 1.8.0
  - systemtags: 1.15.0
  - text: 3.6.0
  - theming: 2.0.0
  - twofactor_backupcodes: 1.14.0
  - updatenotification: 1.15.0
  - user_status: 1.5.0
  - viewer: 1.9.0
  - weather_status: 1.5.0
  - workflowengine: 2.7.0
Disabled:
  - activity: 2.17.0
  - admin_audit
  - bruteforcesettings
  - dashboard: 7.5.0
  - encryption
  - files_external
  - photos: 2.0.0
  - survey_client: 1.13.0
  - suspicious_login
  - twofactor_totp
  - user_ldap

Nextcloud Signing status

No response

Nextcloud Logs

No response

Additional info

Bug found in nextcloud/server/lib/private/Migration/ConsoleOutput.php #78 (see bug description)

[szaimen]

Hi, do you mind creating a PR with your fix? :)

[birnbacs]

Sorry, I am not sure how to do this, maybe you can instruct me how to.

Meanwhile, this is the amended function I just tested successfully:

        /**
         * @param int $step
         * @param string $description
         */
        public function advance($step = 1, $description = '') {
                if (is_null($this->progressBar)) {
                        $this->progressBar = new ProgressBar($this->output);
                        $this->progressBar->start();
                }
                $this->progressBar->advance($step);
                if (!is_null($description)){
                        $this->output->write(" $description");
                }
        }

For those who didn't already know: the progress bar is not updated on every call but only if some progress is perceivable. For testing, I suggest adding a sleep(1); in your loop.

[solracsf]

@birnbacs I've created a PR for you here: #35964
Please comment there if needed 👍