Problems with character encoding conversion on Alpine Linux

[dpavlotzky]

Steps to reproduce

1. Select an email

Expected behaviour

Email should be displayed in de display pane

Actual behaviour

Email is not shown

Mail app

Mail app version: 0.5.3

Mailserver or service: Dovecot with Postfix

Transport security - IMAP: STARTTLS

Transport security - SMTP: STARTTLS

Number of accounts: 1

Mail app version build date: (only if you are using a Nightly Build)

Server configuration

Operating system: Docker container with Alpine Linux

Web server: Nginx

Database: mariadb

PHP version: 7.0.10

Version: 10.0

**Updated from an older version or fresh install: Updated

List of activated apps:

Enabled:
  - activity: 2.3.2
  - admin_audit: 1.0.0
  - calendar: 1.4.0
  - comments: 1.0.0
  - contacts: 1.4.0.0
  - dav: 1.0.0
  - federatedfilesharing: 1.0.1
  - federation: 1.0.1
  - files: 1.5.2
  - files_accesscontrol: 1.1.2
  - files_automatedtagging: 1.1.1
  - files_pdfviewer: 0.8.1
  - files_sharing: 1.0.0
  - files_texteditor: 2.1
  - files_trashbin: 1.0.0
  - files_versions: 1.3.0
  - files_videoplayer: 0.9.8
  - firstrunwizard: 1.1
  - gallery: 15.0.0
  - mail: 0.5.3
  - notifications: 0.3.0
  - password_policy: 1.0.0
  - provisioning_api: 1.0.0
  - serverinfo: 1.1.1
  - survey_client: 0.1.5
  - systemtags: 1.0.2
  - templateeditor: 0.1
  - theming: 1.0.1
  - updatenotification: 1.0.1
  - user_external: 0.4
  - workflowengine: 1.0.1
Disabled:
  - encryption
  - external
  - files_external
  - files_retention
  - user_ldap
  - user_saml

The content of config/config.php:

{
    "system": {
        "apps_paths": [
            {
                "path": "\/usr\/share\/nginx\/nextcloud\/apps",
                "url": "\/apps",
                "writable": false
            },
            {
                "path": "\/data\/nextcloud\/apps",
                "url": "\/ownapps",
                "writable": true
            }
        ],
        "passwordsalt": "***REMOVED SENSITIVE VALUE***",
        "secret": "***REMOVED SENSITIVE VALUE***",
        "trusted_domains": [
            "nextcloud.pavlotzky.nl"
        ],
        "datadirectory": "\/data\/nextcloud\/data",
        "overwrite.cli.url": "http:\/\/localhost",
        "dbtype": "mysql",
        "version": "9.1.0.16",
        "dbname": "nextcloud",
        "dbhost": "mariadb",
        "dbtableprefix": "oc_",
        "dbuser": "***REMOVED SENSITIVE VALUE***",
        "dbpassword": "***REMOVED SENSITIVE VALUE***",
        "logtimezone": "UTC",
        "installed": true,
        "instanceid": "ocpmn05ip3ed",
        "loglevel": 2,
        "maintenance": false,
        "updater.release.channel": "stable",
        "mail_from_address": "nextcloud",
        "mail_smtpmode": "php",
        "mail_domain": "pavlotzky.nl"
    }
}

#### Client configuration

Browser: Google Chrome

Operating system: MacOS Sierra

Logs

Web server error log

Insert your webserver log here

Server log (data/nextcloud.log)

Error   PHP iconv(): Wrong charset, conversion from `utf-8' to `utf-8//IGNORE' is not allowed at /data/nextcloud/apps/mail/lib/model/imapmessage.php#613

##### Horde IMAP log (data/horde_imap.log)

Insert your horde IMAP log here, see https://github.com/nextcloud/mail#debug-mode

##### Horde SMTP log (data/horde_smtp.log)

Insert your horde SMTP log here, see https://github.com/nextcloud/mail#debug-mode

##### Browser log

Insert your browser log here, this could for example include:

a) The javascript console log
b) The network log 
c) ...

[dpavlotzky]

When I change the offending line from

$data = iconv($p->getCharset(), 'utf-8//IGNORE', $data);

to

$data = iconv($p->getCharset(), 'utf-8', $data);

The e-mail get displayed. Same if I use mbstring instead of iconv:

$data = mb_convert_encoding($data, 'utf-8//IGNORE', $p->getCharset());

does not work

$data = mb_convert_encoding($data, 'utf-8', $p->getCharset());

does.

This probably has to do with this functional difference between glibc and musl.

Is the //IGNORE part necessary?

[rnalrd]

I can confirm that removing the "//IGNORE" part it works on Alpine 3.4.

[ChristophWurst]

Fixed in #309.

[halfer]

Related, and possibly of interest to future readers: phpearth/docker-php#3