'retain' parameter with 'include_conf' does not work as expected

[didierm]

Checklist

• [X] I'm reporting a bug
• [X] I've searched the bugtracker for similar issues, including closed ones.

What did you do?

• create base config file base.conf with generic retain parameters

logfile /var/log/base.log
retain daily 7
retain weekly 4 
retain monthly 12

• create instance config file instance01.conf with specific overriding retain parameters

include_conf base.conf

logfile /var/log/instance01.log
retain daily 30
retain monthly 24

• execute rsnapshot

$ rsnapshot -t -c ./instance01.conf daily

What happened?

• expectedly, rsnapshot creates a logfile /var/log/instance01
• unexpectedly, rsnaphot retains only 7 copies of the "daily" backup level

What did you expect to happen

• rsnaphot should retain 30 copies of the "daily" backup level, as the retain daily 30 parameter from the instance01 configuration succeeds, and hence should overwrite the retain daily 7 parameter from the base configuration.

My configuration

see above for a minimal example

Environment

* OS: CentOS Linux 7.9
* Filesystem: XFS
* rsnapshot : v1.4.5

Other information

When including a config file, the contents of the config file are inserted at that specific location :

$ man rsnapshot
...
include_conf       Include another file in the configuration at this point.

• As expected, subsequent parameter values override previous parameter values (cfr. logfile).

• This is apparently not the case for the retain parameter, which seems to add all encountered parameter values to an array, indifferent to already existing "name" backup level occurances.

Remediation :

• only new backup level "name"s should be added to the array ;
• exisiting backup level "name"s should be overwritten with the new "number" value.

Current mitigation :

• include base configs at the end of the instsance config (unwanted, as this prevents overwriting base conf parameters)
• do not define retain parameters in the base config.