Session (.jos) with gpx in subfolder : error loading layer

[StephaneP]

Hi!
When I load a .jos session in Josm (Windows) with a nmea file stored in a subfolder, Josm can't load the file and give me this error:

2019-01-21 18:18:28.112 INFO: Open file: C:\pei\session1.jos (662 bytes)
2019-01-21 18:18:28.166 SEVERE: java.io.IOException: java.net.URISyntaxException: Illegal character in path at index 4: nmea\btnmeatrack_2019-01-19_11-44-01.nmea. Cause: java.net.URISyntaxException: Illegal character in path at index 4: nmea\btnmeatrack_2019-01-19_11-44-01.nmea
java.io.IOException: java.net.URISyntaxException: Illegal character in path at index 4: nmea\btnmeatrack_2019-01-19_11-44-01.nmea
        at org.openstreetmap.josm.io.session.SessionReader$ImportSupport.getFile(SessionReader.java:359)
        at org.openstreetmap.josm.io.session.SessionReader$ImportSupport.getInputStream(SessionReader.java:302)
        at org.openstreetmap.josm.io.session.GpxTracksSessionImporter.load(GpxTracksSessionImporter.java:45)
        at org.openstreetmap.josm.io.session.SessionReader.parseJos(SessionReader.java:563)
        at org.openstreetmap.josm.io.session.SessionReader.loadSession(SessionReader.java:746)
        at org.openstreetmap.josm.io.session.SessionReader.loadSession(SessionReader.java:706)
        at org.openstreetmap.josm.actions.SessionLoadAction$Loader.realRun(SessionLoadAction.java:180)
        at org.openstreetmap.josm.gui.PleaseWaitRunnable.doRealRun(PleaseWaitRunnable.java:95)
        at org.openstreetmap.josm.gui.PleaseWaitRunnable.run(PleaseWaitRunnable.java:143)
        at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
        at java.util.concurrent.FutureTask.run(Unknown Source)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
        at java.lang.Thread.run(Unknown Source)
Caused by: java.net.URISyntaxException: Illegal character in path at index 4: nmea\btnmeatrack_2019-01-19_11-44-01.nmea
        at java.net.URI$Parser.fail(Unknown Source)
        at java.net.URI$Parser.checkChars(Unknown Source)
        at java.net.URI$Parser.parseHierarchical(Unknown Source)
        at java.net.URI$Parser.parse(Unknown Source)
        at java.net.URI.<init>(Unknown Source)
        at org.openstreetmap.josm.io.session.SessionReader$ImportSupport.getFile(SessionReader.java:330)
        ... 13 more

No problem with Ubuntu

[simon04]

Regression of r14630.

[simon04]

In 14723/josm:

see #16497 fix #17228 - Avoid backslashes in session files