I used to package my various Eclipse RCP products with PDE, for years.
With my latest upgrade attempt to Eclipse Oxygen, I got some new strange resolution errors which I could not solve, and I decided it really was time to give Tycho a try. I followed the excellent article about Tycho by Lars Vogel, and after a bit of tweaking, it worked well (and I was not stucked by the same resolution errors as in PDE! Yay!).
But indeed it was a simple test: I created a folder for my bundles, another for my features, created my poms, and so on. Now I look at the degree of automating in my PDE and find quite a huge gap.
In PDE, there is a build.properties where you give your master feature file and a map file, and the process will, seemingly:
(note : the git part needs you provide the egit fetchfactory)
Now in Tycho, I have to create poms, but it is not the problem. I have to create some master poms, and for the individual plugin poms, I have either the pomless option, or the pom generator. The pom generator also seems to have the advantage of creating the parent pom which contains all the plugins as modules. So far so good.
But I have to fill the features and plugins folders, and I'm stuck here. I do not have PSFs for my products, because I never needed it: in PDE, map + product definition does the trick.
Does it mean I will have to maintain PSFs from now on or is there another tycho solution I did not find? (Tycho doc is quite scarce, in my opinion). Maintaining PSFs seems redundant to me because I have product and map, and also because I have many products, many plugins, and many of which are common to several products.
(Indeed, a basic solution would be to take the git repositories mentioned in the map file, dump them all and launch tycho. Tycho would compile all the plugins, and then the p2 part would package only the product-relevant ones. The problem is that I have plenty of different products that rely on plenty of different repositories. And even in a given git repo, I have plugins that may or may not be relevant for a given product. Thus, I would compile hundreds of useless plugins in the process.)
My need is to copy in the tycho folders only the plugins and features which are referenced in my product and which are not already in my target platform. Generating a PSF from my product and my map would be shifting the problem.
Indeed, I can code this, and I will if needed. But given that all this is already automated in PDE, is there at least some parts of the process that could be automated with some tycho plugins I did not uncover?
After some time of digging, here is the solution I finally chose.
In order to fetch the relevant features and plugins, I used... PDE ! I digged in PDE and found the various steps in its process. The first one is to fetch (it is an ant task named eclipse.fetch). I externalized this part, and my script launches it, then generates the master poms by scanning the fetched features names and fecthed plugins names, then adds the other tycho confugurations and then launches tycho.
In the end, granted, it is not a full tycho solution, it is a hybrid one PDE + Tycho. But it works like a charm, and the build/package process is Tycho, only the initial fetch is delegated to PDE. (anyway, PDE build/package process does not work in my case, as stated initially)