Archive:PackagingDrafts/Ada Guidelines Changes

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Contents

Discussion

This is a proposal to make some changes to the Ada packaging guidelines.

Source code in -devel packages

There is currently a rule that a -devel package must not contain all the source files of the library, only those that are necessary for compilation of code that uses the library. I think that this rule costs more than it's worth. It's very difficult for a reviewer to know which files are needed and which ones aren't. The GNAT tools know of course, and will install only the needed files, but not all Ada projects use the GNAT tools to do the installation. Manually keeping track of which body files are needed for recompilation can be error-prone even for upstream developers, so Make-based build systems are likely to just install the complete sources, and it would be a lot of work for a packager to rework makefiles to make them follow the rule.

The code is free so we have no reason to hide it, and disk space won't be an issue on developers' workstations or on build servers. Thus I think the rule should be removed and replaced with a note to the effect that including all body files is not required. We could keep it as a "should not", but then I expect that the guideline would be followed only when the upstream buildsystem follows it. Such a guideline wouldn't make any difference, so it's better to remove it.

Macros with compiler and linker flags

When RPMbuild was packaged it turned out that passing the same command line parameters to RPMbuild as to Gnatmake wasn't optimal, so we replaced GNAT_optflags with two different macros: Gnatmake_optflags and GPRbuild_optflags. It might also happen that some package's build system invokes the underlying GNAT tools directly for some reason, without using Gnatmake or GPRbuild, in which case the packager may need to add some parameters for those tools.

The sentences "The RPM macro %{GNAT_optflags} MUST be used in the compilation. It contains the standard Fedora optimization flags adapted to GNAT." should be replaced with the following paragraph:

The RPM macros Gnatmake_optflags and GPRbuild_optflags expand to Fedora's standard compiler and linker flags adapted for Gnatmake and GPRbuild respectively. The appropriate macro MUST be used in packages that are built with Gnatmake or GPRbuild. In case the package's build system invokes the underlying GNAT tools without using Gnatmake or GPRbuild, then the appropriate macro for each tool MUST be used. If for example Gnatlink is invoked directly, then the expansion of Gnatlink_flags shall be passed to it.

GNAT_arches

Maintainers of some secondary architectures want to prevent build attempts that would always fail because they haven't bootstrapped GNAT on their architectures. A macro has been defined to help with this. I propose to add the following paragraph to the Compilation section:

The macro GNAT_arches expands to a list of architectures where GNAT packages are available in Fedora. Starting with Fedora 18, when there is a need to prevent attempts to build an Ada package on secondary architectures where GNAT has not been bootstrapped, this MUST be done with "ExclusiveArch: %{GNAT_arches}".

_GNAT_project_dir

The value of _GNAT_project_dir has now been changed to "/usr/share/gpr" in Rawhide, so the note about that can be removed.

Category

Although the current Ada guidelines were approved on the 23rd of February 2011, the page is still in the Packaging guidelines drafts category. If I understand the process right it should be moved to the Packaging guidelines category.

Proposed new wording

The full text with the proposed changes follows below.

Packaging Ada programs and libraries

This document describes the current policies for packaging Ada programs and libraries for Fedora. These are Ada-specific amendments to the generic Packaging Guidelines. Ada packages must also conform to the Packaging Guidelines and the Review Guidelines.

Compilation

Devel packages

GNAT project files

Here's an example of what a project file installed with a library may look like: 

with "directories";
project Example is
   for Library_Name use "example";
   for Source_Dirs use (Directories.Includedir & "/example");
   for Library_Dir use Directories.Libdir;
   for Library_ALI_Dir use Directories.Libdir & "/example";
   for Externally_Built use "true";
end Example;

File placement

Rpmlint and Ada packages

Rpmlint is a program that checks packages for common problems. For Ada packages, some of the rpmlint messages, such as "executable-stack", can be disregarded, because GNAT uses trampolines for pointers to nested functions. (See for example this entry in the GCC Bugzilla.)

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