Hi,
I have a repeatable failure with Photon / m2e / wtp projects. I'm not sure it is related with m2e, but as I think it is highly related with the way project's build path is configured, your insight may be important. Also I found no report about this issue, so I think it is not an issue for vanilla Eclipse project.
TLDR; Inspect and Debug shell is impossible in dependencies in a WTP Tomcat Server with Photon (Unable to evaluate the selected _expression_). It used to work with Oxygen. I find a workaround, but this bug is really annoying. Only Debug Server is buggy ; a Debug as... Junit test works fine.
This bug can be reproduced following this steps :
* download jee package for eclipse photon (buildid 20180619-1200, eclipse m2e 1.9.0.20180606-2036, eclipse m2e wtp 1.4.0.20180606-2005)
* with Git Perspective, add the git repository and import the selected project. Maven nature is detected automatically
* create a Tomcat 9.0 Server and add the test webapp
* Debug Tomcat server
* put a breakpoint on TestServlet.doGet
* step in StringUtils.isAllBlank(...)
* perform an inspect or debug-shell on "ArrayUtils.isEmpty(css)"
* it fails with "Unable to evaluate the selected _expression_"
A known workaround for this is :
* click on the stacktrace in debug view
* right-click -> Edit source lookup
* tick Search for duplicate source -> apply
* choose StringUtils.class in the list (opposed to org/apache/commons/...)
* inspect/debug-shell is working again ; but this process must be done for all class you want to debug
Do you reproduce this issue ? Do you think it is m2e related (the way maven project is configured) or wtp related ? How can I help to fix this issue ?
Thanks,
Laurent Almeras