Deleting duplicate plugins (ij.plugin.ClassChecker)

[imagingbook]

ClassChecker "checks for duplicate class and JAR files in the plugins folders and deletes older duplicates": I am not sure about the original purpose of this, since duplicate .class and .jar files cannot exist unless they reside in different packages. That is, plugins with the same names but in different packages should be allowed in general. If duplicate "command names" are a problem, the package names could be included.

Apart from this, there appear to be 2 issues with ClassChecker as it is now:

1. Deletion does not work properly. Assume there are 3 plugins with the same name My_Inverter.class in three packages A, B, C, with identical modification dates. In this case, only A.My_Inverter.class is deleted, but 3 times in a row:

   Deleting duplicate plugin: D:...\ImageJ\plugins\A\My_Inverter.class
   Deleting duplicate plugin: D:...\ImageJ\plugins\A\My_Inverter.class
   Deleting duplicate plugin: D:...\ImageJ\plugins\A\My_Inverter.class
   

2. Compiled package-info.class files should be ignored, since they cannot contain plugin code. They should be allowed to exist, there is no reason to delete them at all:

   Deleting duplicate plugin: D:...\ImageJ\plugins\A\package-info.class
   Deleting duplicate plugin: D:...\ImageJ\plugins\A\package-info.class
   

One more issue: The deleted .class files get nevertheless listed in the Plugins menu, so when a user selects any of these a "class-not-found" error occurs!

[rasband]

Hi Wilhelm,

Do you any suggestions for how the ClassChecker can be modified to fix these issues?

[imagingbook]

Sure, I'd be happy to fix it but I am still unclear about its intent. Apparently ClassChecker is supposed to find plugins with identical names in (evidently) different packages and delete all but the most recent .class file.

• I find the idea of purging .class files a bit irritating and do not see why deletion of duplicates is necessary at all.
• What happens if identically named plugins are loaded from a JAR file? Seems in this case ClassChecker can't do anything.

I tried to run ImageJ with ClassChecker completely deactivated and it seems to be doing just fine. So perhaps it could be removed all together, or I have overlooked something?

[rasband]

The ImageJ 1.53s6 daily build deactivates ClassChecker except when the Compile and Run command is used.

[rasband]

The ClassChecker in the ImageJ 1.53s7 daily build displays warning messages but no longer deletes files. It only runs when you use the Compile and Run command, which typically creates class files that are not in a package.

[imagingbook]

I cannot see this change in this repo. Has the 1.53s7 build been pushed?

[rasband]

The new 1.53s10 commit has all the ClassChecker changes.