Tx for the report
On Wed, Aug 16, 2017 at 11:31 PM, bdurin <bruno.du...@gmail.com> wrote: > Hi, > > I stumbled upon what seems to me a strange issue in Pharo 5. The RBParser > fails to correctly parse the legacy FFI pragmas. This completely breaks down > the browser, the inspector and debugger (because as far as I understand all > use RBParser to correctly highlight syntax). I had the image crashed and > some red boxes at some point while insisting to inspect and debug. Overall > this is not a big issue but it raises some more general bells to me. > > In order to reproduce this: > - load the official Pharo 5 (curl get.pharo.org/50+vm | bash) > - launch the image (./pharo-ui Pharo.image &) > - add the following repository > MCSmalltalkhubRepository > owner: 'panuw' > project: 'zeromq' > user: '' > password: '' > - load the last versions of ZeroMQ and ConfigurationOfZeroMQ (not sure if > the latter is needed) > - open a Nautilus Browser and look at the class method apiZmqBind:to: of the > ZmqApi class in the ZeroMQ package: you get a MessageNotUnderstood error > (receiver of keywords is nil). You can get past this by clicking on > "Abandon" but the source code is displayed in a corrupted way: > apiZmqBind: s > ocket to: endpoint <cdecl > - repeat a few times by looking at other methods until you get a red box: > then you cannot look at source code any more with this browser. If you are > obstinate and "lucky" you will succeed in crashing the image. > - you can pin the problem by running in a Playground > RBParser parseFaultyMethod: 'apiZmqBind: socket to: endpoint > <cdecl: long ''zmq_bind'' (ZmqApiSocket* char*) module:''zmq''> > ^self externalCallFailed'. > and you'll see that the pragmas is not correctly parsed. (The root cause is > that the legacy adapter RBFFICallPragma does not follow the API defined by > its super class RBPragmaNode (selector, arguments, positions) and so is not > a properly defined node. I corrected the problem by computing and setting > the corresponding instance variables.) > 1) As a beginner at Pharo, I find it difficult to deal with the various > versions of Pharo. ZeroMQ is the (only) Smalltalk-Pharo binding for zmq. It > dates back to Feb 2014 so I expected it to work in Pharo as of 3 years and a > half later (Pharo 6 dates back to June 2017). We maintain actively 2 versions on 5 OSes. On many system old libraries do not work on new versions. By definition I never believe that a version of Mac OS 9 is working on Mac OS 11 and Mac has a lot of money. A lot more than us. > I naively tried to load the package in a Pharo 6 image and it failed because > of a syntax error. As I had read a lot about the various FFI mechanisms, I > quickly understood that it must be because the FFI declarations in pragma > are not supported anymore. They still are but you probably hit an edge case. > I then loaded the package in a Pharo 5 image and I got the error that I > described. After finding the error and solving it, I guess that the FFI > declaration in pragma was barely supported in Pharo 5, which has already > switched to UFFI and that it is something dating back to Pharo 4. (I did not > try with Pharo 4 as I do not want to work with versions before 5). Normally we took care to be backward compatible to ease moving from one version to the other one. Esteban was on vacation and I asked him to have a look. > Is there a way to know for a package what the compatible Pharo version is? > It seems that currently I have to look at dates, look at the features used > by the package and look for the history of development (fortunately the > mailing lists are easy to search) to understand which version is likely to > work. People should - publish their package in the catalog of a given version. - have test - have a configuration because this configuration list also the version of Pharo. > Are not deprecations a bit too fast if a package written 3 years ago cannot > work in the latest Pharo version and trigger bugs in Pharo 5, which dates > back to May 2016 (so only a bit more than 2 years after)? This is not a deprecation. This is probably just a case that was not handle. We spent 8 months developing a new FFI and there is still points to be added. > I find it a bit too fast as compared to mainstream languages. To my mind, > either deprecations should be slower or a version/dependencies system should > be there to help users. Please do not generalise from one case. We pay attention to make sure that people can move. Now > > 2) Another question about versions: Pharo 6 is out since June, Pharo 7 is > under development. What is the status of Pharo 5? Already history or still > relevant? We do not actively back port fix to Pharo 50. But you can execute Pharo 50 and we build regularly vms. > I am asking because I corrected the problem of FFI declaration in pragma, > but it seems to me that it is not useful to publish this change as starting > from Pharo 6 this way to do FFI is not supported. So should I contribute? Please send your fixes so that we can have a look at it. > yes, how to "attach" the patch to Pharo 5? You can - open a bug entry and publish a slice in the Pharo50Inbox - fileout your changes and send them to the mailing-list to start with. > > 3) As explained above, in Pharo 5, looking at the source trigger an error. > Even if this looks like a rare corner case, I think that the developer tools > should not trigger bugs when looking at source code, even less trigger a red > box in the source code viewer (in the browser, but the problem also occurs > --less strongly-- when looking at the object in an inspector: there should > not be "error printing" when it is only a syntax highlight problem). If the > code is malformed and the parser used to highlight syntax fails, there > should be a fallback such as the source code being displayed without any > highlight. It sends a very bad impression to have this kind of bugs when one > simply wants to look at code, not even running it. Yes you are correct. > I have not dug enough in this area of Pharo, but it seems to me that the > parser that is used to build the AST for code execution / method compilation > should not be the same as the parser used to highligh syntax. (Of course I > am not saying that there should be 2 distincts code base for the 2 parsers, > but they should at least run differently.) The first one must be strict with > errors as a malformed AST cannot be executed. The second one must be > lenient, as a malformed AST does not prevent to print the string of the > source code. Of course, at the end if the code is malformed there will be an > error at execution, but if the source code can be displayed even when it is > malformed, at least I have the opportunity to correct it so that it runs > correctly. (In this case, convert the old FFI pragma declaration into a > fficall:) This is more than that. A parser error should not blow up the UI. This is a problem in the current architecture. Pharo is not perfect but we are working on it. > I may be missing something here but if this works the same in the most > up-to-date version of Pharo, the same kind of error might appear again. > What do you think? We have a long list of improvements that we should do. Pharo is not perfect. It is what we have now and that we use daily, improve daily but developing robust and good quality software is taking a lot of time. We have to prioritize for each version. Now we make progress. Each version of Pharo is getting better. > > 4) A final remark: let us classify people as Beginner/Confirmed in > programming and B/C in Pharo (A BB is a beginner in programming and in > Pharo, a CC confirmed in both, a BC cannot exists and CB are those who > discover Pharo while knowing well other languages). Pharo seems to be great > for BB and CC. I went through the MOOC and the various books which are > great. My first steps in Pharo environment were great. > As a CC it seems to be great also as in the very small area of the system > where I took the time to drill into all the details, I could very easily > change things (and correct a bug), that would have been very difficult to > understand and change in a lot of other languages. Even hacking the VM seems > to be possible for a non-VM expert. > But I consider myself rather as a CB. As such I tend to try and do complex > things that I usually do in other languages and run into tricky problems. > These problems are rather dealt with and corrected by Pharo developers but > that as a user I would expect them to remain hidden to me or to be clearly > advertised in the docs. As compared to a BB, a CB is not going to stay in a > well delimited area where everything is smooth. > True, in a way it is a very strong incentive to become a Pharo expert! But I > am wondering if this aspect could be improved. Freedom of action is a two edge sword. We are concerned by that aspect. Now often it is not easily to hide and reveal on demand a reflective system. Stef > > Thanks, > Bruno > > > > -- > View this message in context: > http://forum.world.st/Parser-failure-on-FFI-pragmas-declaration-in-Pharo-5-tp4961737.html > Sent from the Pharo Smalltalk Users mailing list archive at Nabble.com. >
