Russ Allbery <r...@debian.org> (30/06/2010): > Here's a proposed patch that I think says what we now want to say about > *.la files. Objections or seconds? > > diff --git a/policy.sgml b/policy.sgml > index 9fe7158..2635fa8 100644 > --- a/policy.sgml > +++ b/policy.sgml > @@ -7361,40 +7361,58 @@ strip --strip-unneeded <var>your-lib</var> > </p> > > <p> > - An ever increasing number of packages are using > - <prgn>libtool</prgn> to do their linking. The latest GNU > - libtools (>= 1.3a) can take advantage of the metadata in the > - installed <prgn>libtool</prgn> archive files (<file>*.la</file> > - files). The main advantage of <prgn>libtool</prgn>'s > - <file>.la</file> files is that it allows <prgn>libtool</prgn> to > - store and subsequently access metadata with respect to the > - libraries it builds. <prgn>libtool</prgn> will search for > - those files, which contain a lot of useful information about > - a library (such as library dependency information for static > - linking). Also, they're <em>essential</em> for programs > - using <tt>libltdl</tt>.<footnote> > - Although <prgn>libtool</prgn> is fully capable of > - linking against shared libraries which don't have > - <tt>.la</tt> files, as it is a mere shell script it can > - add considerably to the build time of a > - <prgn>libtool</prgn>-using package if that shell script > - has to derive all this information from first principles > - for each library every time it is linked. With the > - advent of <prgn>libtool</prgn> version 1.4 (and to a > - lesser extent <prgn>libtool</prgn> version 1.3), the > - <file>.la</file> files also store information about > - inter-library dependencies which cannot necessarily be > - derived after the <file>.la</file> file is deleted. > + Packages that use <prgn>libtool</prgn> to create and install > + their shared libraries install a file containing additional > + metadata (ending in <file>.la</file>) alongside the library. > + For public libraries intended for use by other packages, these > + files normally should not be included in the Debian package, > + since the information they include is not necessary to link with > + the shared library on Debian and can add unnecessary additional > + dependencies to other programs or libraries.<footnote> > + These files store, among other things, all libraries on which > + that shared library depends. Unfortunately, if > + the <file>.la</file> file is present and contains that > + dependency information, using <prgn>libtool</prgn> when > + linking against that library will cause the resulting program > + or library to be linked against those dependencies as well, > + even if this is unnecessary. This can create unneeded > + dependencies on shared library packages that would otherwise > + be hidden behind the library ABI, and can make library > + transitions to new SONAMEs unnecessarily complicated and > + difficult to manage. > </footnote> > + If the <file>.la</file> file is required for that library (if, > + for instance, it's loaded via <tt>libltdl</tt> in a way that > + requires that meta-information), the <tt>dependency_libs</tt> > + setting in the <file>.la</file> file should normally be set to > + the empty string. If the shared library development package has > + historically included the <file>.la</file>, it must be retained > + in the development package (with <tt>dependency_libs</tt> > + emptied) until all libraries that depend on it have removed or > + emptied <tt>dependency_libs</tt> in their <file>.la</file> > + files to prevent linking with those other libraries > + using <prgn>libtool</prgn> from failing. > + </p> > + > + <p> > + If the <file>.la</file> must be included, it should be included > + in the development (<tt>-dev</tt>) package, unless the library > + will be loaded by <prgn>libtool</prgn>'s <tt>libltdl</tt> > + library. If it is intended for use with <tt>libltdl</tt>, > + the <file>.la</file> files must go in the run-time library > + package. > </p> > > <p> > - Packages that use <prgn>libtool</prgn> to create shared > - libraries should include the <file>.la</file> files in the > - <tt>-dev</tt> package, unless the package relies on > - <tt>libtool</tt>'s <tt>libltdl</tt> library, in which case > - the <tt>.la</tt> files must go in the run-time library > - package. > + These requirements for handling of <file>.la</file> files do not > + apply to loadable modules or libraries not installed in > + directories searched by default by the dynamic linker. Packages > + installing loadable modules will frequently need to install > + the <file>.la</file> files alongside the modules so that they > + can be loaded by <tt>libltdl</tt>. <tt>dependency_libs</tt> > + does not need to be modified for libraries or modules that are > + not installed in directories searched by the dynamic linker by > + default and not intended for use by other packages. > </p> > > <p>
Sounds good to me, thanks. Seconded. Mraw, KiBi.
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