IO SFTP - wrong constants in write method

[mb-tec]

Preconditions

Magento 2.1.5

Steps to reproduce

File upload via SFTP to remote Server

Expected result

File upload works

Actual result

Exception thrown:
Notice: Use of undefined constant NET_SFTP_LOCAL_FILE - assumed 'NET_SFTP_LOCAL_FILE' in
.../magento/vendor/magento/framework/Filesystem/Io/Sftp.php on line 187

Wrong code: $mode = is_readable($source) ? NET_SFTP_LOCAL_FILE : NET_SFTP_STRING;
Should be: $mode = is_readable($source) ? \phpseclib\Net\SFTP::SOURCE_LOCAL_FILE : \phpseclib\Net\SFTP::SOURCE_STRING;

[veloraven]

@mb-tec thank you for your report.
This issue has already been fixed in develop #6894
And we have internal ticket for fixing it in ver. 2.1 - MAGETWO-67470

[rikwillems]

This issue is still present in 2.1.8. I solved it with a preference that overrides the write method according to db17419
provided in #6894.

[magento-engcom-team]

@mb-tec, thank you for your report.
The issue is already fixed in develop branch, 2.2.0