On 04/01/2014 01:46 PM, Jiri Vanek wrote: > On 04/01/2014 01:28 PM, Mikolaj Izdebski wrote: >> Fedora 21 will likely introduce so called "weak" or "soft" dependencies, >> also known as recommends and suggests. For proposed change see [1]. >> What do you think about Java packages adopting usage of weak >> dependencies? >> >> An example: Dependencies declared as optional in POM files could be >> translated by dependency generators to Recommends instead of Requires. >> >> Any thoughts on this? >> >> [1] https://fedoraproject.org/wiki/Changes/RPM-4.12 >> > > There is always issue that end users will hardly know why, should he > install something and mostly there is no nice dialogue "This feature > works only when you download also .....(and put it on classapth)" Not > mentioning that upstreams do not care about "to enable this feature yum > install someRpm" > > Well I have (me-touching) example in mind. IcedTea-Web have "weak" > dependence on tagsoup. Well it works without it, but then some JNLP > files are not parsed. User get jsut "invalid xml" exception in this > case. So he will have no clue, that he should install tagsoup, > > Will there be any mechanism for this? I doubt:( > > TBH - I can come only with one good usage - to use soft dependence > *only* for dependence which are not in fedora. Once it is packed, lets > it be installed all. I don't think what you described here is the behaviour of Recommends. If package A recommends B then by installing A you also install B, unless something conflicts with it or obsoletes it. After installing A you can erase B without breaking dependencies. Example. Lets assume we have package maven with: Requires: java-headless Recommends: java-devel Suggests: maven-doc When you do "yum install maven", YUM should print something like: Installing: maven Installing for dependencies: java-1.8.0-openjdk-headless Installing recommended dependencies: java-1.8.0-openjdk-devel You may also consider installing: maven-doc Maven obviously cannot run without java-headless, so hard requirement is used here. Maven is usually used to compile Java sources, hence Recommends on java-devel. But Maven itself works perfectly fine without java-devel, so users can erase java-devel after installing maven, if they want to. java-devel is a dependency that most users would expect, so it is "recommends". maven-doc is just added as suggestion and it will not be pulled by yum with default settings. It's added there just to point users to other useful resources. -- Mikolaj Izdebski Software Engineer, Red Hat IRC: mizdebsk -- java-devel mailing list java-devel@xxxxxxxxxxxxxxxxxxxxxxx https://admin.fedoraproject.org/mailman/listinfo/java-devel
