[patch] session reader failed when linked local file was compressed

[kolesar]

What steps will reproduce the problem?

1. Save a data layer in a compressed format, for example test.osm.gz
2. Save session, leave setting as a "local file".
3. Close layer.
4. Open recently created session file.

What is the expected result?

Opens the layer just created.

What happens instead?

Error message:

    Could not load layer 1 'test.osm.gz'.
    Error is:
    Line 1 column 1: Content is not allowed in prolog.

Similar error message for compressed GPX layer:

    Could not load layer 2 'test.gpx.gz'.
    Error is:
    Parsing data for layer 'test.gpx.gz' failed

Please provide any additional information below. Attach a screenshot if possible.

Attached patch that fixes opening compressed files from saved session.

[Don-vip]

In 9646/josm:

fix #12448 - session reader failed when linked local file was compressed (patch by kolesar)

[Don-vip]

thanks for the patch! :)