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If the dependencies <import plugin="org.eclipse.help"/> <import plugin="org.eclipse.help.ui"/> <import plugin="org.eclipse.help.webapp"/> <import plugin="org.eclipse.tomcat"/> are not stated in plugin.xml, the help system won't work, there is no explanation why it won't. Reproduce by downloading Ed Burnett's org.eclipse.ui.tutorial.rcp.part3 and run it according to his instructions in http://dev.eclipse.org/viewcvs/index.cgi/%7echeckout%7e/org.eclipse.ui.tutorials.rcp.part3/html/tutorial3.html Then delete the above mentioned entries in plugin.xml, do run - debug - plug-ins and "deselect all", select "org.eclipse.ui.tutorials.rcp.part3" and "add required plug-ins". There is no indication why help won't work now. Without Ed's tutorial it is difficult to find out the needed dependencies (debug the source code?).
The standard help action, HelpContentsAction (created by ActionFactory.HELP_CONTENTS.create(...)) calls WorkbenchHelp.displayHelp(). This has no effect if no help UI is installed -- it currently fails silently. We should log a message in this case, and bring up a dialog telling the user that no help UI is installed. However, it won't be able to provide more help than this as to which plugins are missing, since the Help UI is pluggable -- you can have different implementations of it. I'll add an entry to the RCP FAQ indicating which plug-ins are required for the default Help UI though.
Konrad, in Ed's tutorial part 3 (project org.eclipse.ui.tutorials.rcp.part3), the plugin.xml brings in the Help UI using: <import plugin="org.eclipse.help.ui"/> <import plugin="org.eclipse.help.webapp"/> <import plugin="org.eclipse.tomcat"/> Could you explain why it's necessary to include webapp and tomcat separately? Why aren't these included by help.ui? Are these only needed if the help content uses JSPs? Is it possible to run Help UI without them?
Note that the tutorial includes these just for the benefit of making Add Required Plugins work in PDE. The tutorial does not refer to anything in these plugins directly.
Combination of optional/replacable requirements. org.eclipse.help.ui is optional or replacable in RCP. org.eclipse.help.ui assumes help is web based and requires an implementation. org.eclipse.help.webapp is the default implementation contributed through extension point to org.eclipse.help.base. It is replacable. org.eclipse.help.webapp requires some server to run. org.eclipse.tomcat is the default implementation contributed through extension point to org.eclipse.help.appserver. The implementation is replacable. From the above, org.eclipse.help.ui cannot require neither org.eclipse.help.webapp nor org.eclipse.tomcat. The dependency cannot be added the other way either, because in stand-alone help or infocenter, org.eclipse.help.webapp and org.eclipse.tomcat need to run without org.eclipse.help.ui (with UI dependencies).
Great, thanks for the clarification/reminder.
Should still give a warning dialog if no help is installed.
this should be noted in the RCP FAQ and fixed in 3.2
Reassigning bugs in component areas that are changing ownership.
Sorry, I did not have time to address this for 3.2. At least, the RCP FAQ seems to be up to date regarding the list of plug-ins required for help to work.
deferring
Prakash is now responsible for watching bugs in the [RCP] component area.
Created attachment 175747 [details] Patch v01
Patch v01 released to HEAD. The error message is logged now.
verified in I20101025-1800 via code inspection
