17 messages in org.apache.myfaces.devRe: [DISCUSS] how to get rid of tons ...| From | Sent On | Attachments |
|---|---|---|
| Mark Struberg | Oct 22, 2011 4:08 pm |  .txt |
| Jakob Korherr | Oct 23, 2011 2:59 am | |
| Mark Struberg | Oct 23, 2011 8:55 am | |
| Jakob Korherr | Oct 23, 2011 9:14 am | |
| Leonardo Uribe | Oct 23, 2011 11:27 am | |
| Leonardo Uribe | Oct 23, 2011 12:08 pm | |
| Mark Struberg | Oct 23, 2011 3:37 pm | |
| Leonardo Uribe | Oct 23, 2011 7:35 pm | |
| Mark Struberg | Oct 24, 2011 1:37 am | |
| Leonardo Uribe | Oct 24, 2011 10:17 am | |
| Mark Struberg | Oct 24, 2011 3:14 pm | |
| Leonardo Uribe | Oct 24, 2011 3:29 pm | |
| Leonardo Uribe | Oct 24, 2011 7:02 pm | |
| Mark Struberg | Oct 24, 2011 11:38 pm | |
| Mark Struberg | Oct 25, 2011 4:32 am | |
| Leonardo Uribe | Oct 25, 2011 8:47 am | |
| Mark Struberg | Oct 25, 2011 9:23 am |
| Subject: | Re: [DISCUSS] how to get rid of tons of duplicated code | |
|---|---|---|
| From: | Leonardo Uribe (lu4...@gmail.com) | |
| Date: | Oct 23, 2011 7:35:46 pm | |
| List: | org.apache.myfaces.dev | |
Hi
2011/10/23 Mark Struberg <stru...@yahoo.de>:
I've now read through the old mail archives and understand what the original
problem was. But actually I don't think we solved it correctly right now. Of
course we solved to original problem, but opened a can of worms causing other
problems.
The problem as far as I remember has been that myfaces-shared had tons of
duplicated code in it. One for core, one for tomahawk, one for trinidad, etc.
The shared part for core got moved to myfaces-core, but the deeper problem was
that it was not easily possible to have multiple different versions of
myfaces-shared. This now got solved by using the maven-shade-plugin. So we
should rethink the practice to duplicate all the code and aim for a _clean_
solution.
Really that was not solved using maven-shade-plugin. What we did was copy the code into myfaces-core and create a mirror of the same code under shared. There, there is a profile called "synch-myfaces-impl-shared", when it is added, the code is copied and then a manual commit do the trick.
Also (being a maven guy) I cannot quite follow the argument about the release
cycles. Running a myfaces-shared release and then (with the same staging repo) a
myfaces-core release is a task of 15 minutes. + the time for running the TCK,
but this gets run via CI anyway, right? Thus this is barely a problem.
If it is then I'd happily volunteer to do the next release (do this for a few
projects already) As you know, performing a release really got _much_ easier
nowadays with our new apache-parent pom.
But maybe this argument was only meant for our old release process (which I
agree was a lot of work)?
If your answer is 'it's still needed' then can we just unify all other usages?
Make a release is just the first of the problems. Take into account that each release requires a vote and that vote takes 3 days to get fixed. So in practice a problem in core can effectively block a release of other artifacts. That's very inconvenient. Suppose we have a new TCK and that one found a problem on myfaces core. Again even if the other artifacts are good enough, this becomes a blocker. There are enough historical evidence that supports this point. In conclusion this slow down the whole release cycle we have on myfaces. So ignore that is not an option.
Instead, maybe the option is reorganize myfaces core to allow alternate release lifecycles per module. For example, each maven plugin in myfaces has its own release lifecycle and there is a parent pom with a different release procedure. This requires some changes to create the source-release.zip file inherited from apache pom. But it could be a cleaner solution.
This means myfaces-commons project should be "merged" in some way with myfaces core. It has sense.
One question which bothers me with the 'shared' approach if what would happen to
our build-tools annotation scanning (@JSFWebConfigParam, etc)? Does this already
work with dependencies? Do we have this problem already due to the fact that we
import such annotated classes via dependency?
Those annotations comes from myfaces-builder-annotations. They are source code annotations but all that information are saved on myfaces-metadata.xml, so even if dissapear on compile time, the information can be gathered from there. It is not a problem.
Additionally, we increase the risk of "side effects", because a change done in core could introduce a bug in other parts.
Imo it's exactly the opposite. If you use the same code in 7 projects, then it
is more likely that a bug gets found and fixed.
And the opposite case is (sadly) absolutely unlikely. If you have a class
duplicated 7 times and find a bug in one project, it is highly unlikely that all
6 other projects will get this fix applied :(
But what happen when you have some code that does not have a clear "interface". If somebody removes or change some code because he/she thinks it is not used in core or whatever, all 6 projects that could require it will be affected and will require to rework its code. Things get uglier when you have one library working with version 1.1.1 and 1.1.2 is binary incompatible with version 1.1.1, but my other dependency requires it and kaboooom, the application does not work. So, the first assumption we need to preserve in those "shared" artifacts is build it as an API, preserving binary compatibility.
So we can't just grab the code from shared as is and say to users "... you can use that into its own projects ...". If the project is maintained inside myfaces we can fix such problems, but outside myfaces we should be more strict. So, we need a "public shared" code like the one proposed in myfaces commons and other code "myfaces shared" to use in projects like tomahawk or portletbridge or whatever inside our land.
regards,
Leonardo Uribe
LieGrue, strub
----- Original Message -----
From: Leonardo Uribe <lu4...@gmail.com> To: MyFaces Development <de...@myfaces.apache.org> Cc: Mark Struberg <stru...@yahoo.de> Sent: Sunday, October 23, 2011 9:08 PM Subject: Re: [DISCUSS] how to get rid of tons of duplicated code
Hi
Ok, let's check the proposal
MS>> So the suggestion is: MS>> MS>> 1.) cleanup myfaces-shared. mf-shared has almost no checkstyle rules applied.
Yes, sounds good.
MS>> 2.) add unit tests for myfaces-shared. Currently there are not many...
Ok, sounds good too.
MS>> 3.) move the shared code parts back to myfaces-shared and add unit tests.
So, this means do one step back and move the code from myfaces-core "shared" to myfaces-shared project? This breaks effectively the changes done some months ago to make easier work with myfaces core itself.
In that time the conclusion was: "core has priority over anything else, so shared code must live in core, but myfaces-shared project should just copy the code from there and have its own lifecycle" (these are my own words as I understood).
So this point does not have practical sense, and go against everything discussed earlier.
MS>> 4.) import myfaces-shared via maven dependency and use <minimizeJar> and <relocations> to package the stuff
maven-shade-plugin is a good "tool" but doesn't fit well in this scenario. The reason is we need an alternate release lifecycle for the shared code between myfaces core and other projects.
Historically that was the very first intention behind myfaces-shared project. Any myfaces core release requires some additional steps to do (TCK), so that becomes a problem when you try to release other libraries that depends of shared. So, to fix that, "shared" was created, so the code can be released in a independent way, and prevent myfaces core becomes an obstacle to release any other project (tomahawk, portlet-bridge, ... ). So, to release tomahawk you release shared first and then tomahawk.
maven-shade-plugin requires a released artifact to do its job. So, use it impose that restriction. In "shared" case, preserve the original intention becomes "imperative", and that's the reason why a goal was created to copy the code from myfaces-core shared, so the release manager can run this goal, commit the changes and then run a release.
My proposal in this case is do the same we did for shared, but for "myfaces commons" case. Then we can use maven-shade-plugin in other projects, but not over shared, instead over a released version of myfaces-commons-utils. Keep tomahawk or portlet-bridge as is, using shared project, because by its nature, those projects require classes that are not meant to be used outside those cases.
Note do any hack in this part makes a little bit "obscure" how to make changes, because everything becomes "centralized", but makes easier maintain code. Additionally, we increase the risk of "side effects", because a change done in core could introduce a bug in other parts. So at the end this is a matter of how to keep our code "balanced", even if some times it becomes a decision about "choose the less inconvenient alternative".
regards,
Leonardo Uribe
2011/10/23 Leonardo Uribe <lu4...@gmail.com>:
Hi
2011/10/23 Jakob Korherr <jako...@gmail.com>:
Hi Mark,
+1 - that's exactly what I have been trying to accomplish some time ago (introducing common-shades [1]). Unfortunately, I was not successful back then.
It is clear we need to "split" myfaces-impl into multiple modules. There are some parts that are useful for other projects. The code you did on commons-shade was the attempt to solve the problem of the duplicate code used on myfaces-test.
Now the objective is find a way about how to reuse code in myfaces core between multiple projects effectively.
However, there is a slight problem with moving all this stuff into MyFaces shared, which I want to point out: code size. If we really put all the code that is shared across any MyFaces subproject into shared, it will get fat and ugly (even more than it is right now). In addition, if we continue including the whole shared project into MyFaces core, MyFaces core impl will get bigger and bigger.
Yes, the problem basically is MyFaces shared does not have any order or any notion of API. There are code that is used only in tomahawk but not intended to use in any other place. There are some useful utitlities but sometimes without documentation, and there are some other code that is just obsolete. It it clear a cleanup of that location is necessary, but note priorities comes first, so this task has been delayed in order to deal with other important stuff. Now it is a good time to fix this.
Thus I'd like to suggest something similar which I wanted to accomplish with common-shades: Introduce a new shared module, which consists of many submodules that each handle a specific functionality instead of being one fat module. With this approach each MyFaces subproject would be able to pick out only the stuff it really needs. Furthermore we would see more easily which code in shared is not used anymore (I guess at the moment there is a lot of it), just by checking which modules are still used in our poms.
That is the big question, how to split myfaces-impl and shared. Precisely the intention of myfaces-commons-utils projects was take the stuff that is useful from shared and build an usable API for developers outside MyFaces.
For example, MyFaces HTML5 subproject was a good experiment to see which code is useful and should be added in a API. Some weeks ago I checked and removed all duplicate code to use myfaces-commons-utils. So the 1.0.2 release contains those classes taken from shared.
regards,
Leonardo Uribe
Regards, Jakob
[1] https://svn.apache.org/repos/asf/myfaces/common-shades/
2011/10/23 Mark Struberg <stru...@yahoo.de>:
Hi! While working on the mafyces-commons cleanup I figured that we have tons of duplicated code spread over MyFaces.
As an example I like to mention myfaces-commons-resourcehandler. There are 43 classes in total, and 35 of them are just 1:1 copied from other projects to provide resource management, zip, etc. For me this is an absolute no-go. Those classes have neither tests nor any documentation where they got forked from. Nor will any bug which gets fixed in another module make it's way over to all the other projects containing that very forked code. That's just ... unbelievable unmaintainable.
There are 2 different ways to solve this (depending on the problem):
A.) drop the functionality and provide a generalized solution. The GZIP of myfaces-commons-resourcehandleris an obvious example: We now copy this code over the 4th time or even more. Instead of doing this, we should rather do it in the classic unix fashion: do one thing, but do it well. Which means I'd rather see all the GZIP stuff factored out into an own mf-commons module as a Servlet Filter. This can then get applied to what ever other mechanism you like. This could also (commonly) cover cases like detecting http UserAgents which are not able to handle zipped resources, etc. That way we could provide this logic ONCE and have complete freedom over the configuration.
B.) code reusable components once and use them in other projects (ev via shading it in). ClassLoaderResourceLoader would be a perfect candidate! I grepped through only the few pits which I have checked out locally and found this class 7 SEVEN times! I just can't believe that we can't move this stuff to a shared modul...
Same for FacesServletMapping. 6 times copied around, WebConfigProviderFactory 5 times, ... There are whole packages with 10++ classes which got copied 1:1!
I really could cry seeing this :(
What can we do to solve this?
Theoretically myfaces-shared should contain this stuff. This is exactly what it is for! Historically there have been some hand forged tweeks and ugly hacks, but nowadays we have the maven-shade-plugin to make our live easier.
So the suggestion is:
1.) cleanup myfaces-shared. mf-shared has almost no checkstyle rules applied. 2.) add unit tests for myfaces-shared. Currently there are not many... 3.) move the shared code parts back to myfaces-shared and add unit tests. 4.) import myfaces-shared via maven dependency and use <minimizeJar> and <relocations> to package the stuff
[+1] fine go ahead (ideally: yes, what parts can I help with?) [0] dont care [-1] wont work because ...
I've attached a file which contains all Classes which name exists multiple times in MyFaces. The number is the cound how often they exist in MyFaces. I excluded current20. Please note that classes with the same name do not necessarily have the same content - but quite a lot actually do have! (scroll to the bottom of the file ...)
LieGrue, strub
-- Jakob Korherr
blog: http://www.jakobk.com twitter: http://twitter.com/jakobkorherr work: http://www.irian.at