Re: Testing platform

[Dr. David Kirkby]

Ralf Wildenhues wrote:
> Hello David,
>
> * Dr. David Kirkby wrote on Thu, Oct 15, 2009 at 11:53:01PM CEST:
> > I've got this bit of code, which checks for 'bash'. The user does
> > not need to use the bash shell, but many scripts assume the back
> > shell and will fail otherwise (no, I did not write them myself!)
>
> The first question that comes up is: what is $foobar used for?
> If it is needed for executing the configure script itself, then
> this is the wrong approach, and Autoconf should let you integrate
> your requirements in its better-shell search (which is currently
> possible only using the undocumented _AS_DETECT_REQUIRED macro).

foobar was only intended to do the test to find if bash was in the path 
or not. Other than in the lines I showed, it is not needed.

In fact, this whole configure script does need to produce a working 
makefile (such a file is never used). The idea of this script is to 
check that the build environment are sane and has all the requirements 
to build all parts of Sage (some 250 MB compressed). We want to avoid 
someone starting to build Sage, spending several hours doing so, then 
only to find their version of perl is too old to build a package that 
requires a specific version. We would rather highlight any issues we can 
think of as soon as possible. One issue would be them not having bash in 
their path.

Other programs in Sage will have their own configure scripts to actually 
build the code. The script I wrote checks things like

* CC and CXX do not contain a mix of GNU and non-GNU compilers
* Perl on the system is not too old.
* GCC version (if gcc is used) is not 4.0.0, as that version has known 
bugs.
* If gcc and g++ are used as compilers, they are the same version.
* gcc and g++ if used are not too old.
* Warns if non-GNU compilers are used, as Sage has never been built 
without a GNU compiler, though it is my aim to make it build with Sun 
Studio.

So this script is only for checking the perquisite parts are present.

Any makefile produced is ignored. In fact, I should remove the line of 
code which creates the makefile, if there is one there, which I think 
there is.

> If you need it while building the package, i.e., on the $build system,
> then an automatic search seems ok.  I'd however use AC_PATH_PROG, and
> use its fourth argument to append, say, /opt/OpenSource/bin and
> /opt/pware/bin and maybe /opt/freeware/bin or so to the path for
> searching.

If bash is not in the users path, the build process will fail, due to 
things totally outside the control of this configure script. So if bash 
is not in the path, an error must be produced. I guess it would be 
useful to tell them where to find bash on their system if its not in 
their path, so perhaps doing a search for them would be useful. But even 
if bash is found, but is not in their path, the script must exit with an 
error.

> If you need $foobar on the $host system (i.e., after 'make install'),
> then an automatic search only makes sense if you are not building for
> another system, be that because you're cross-compiling, or just because
> the other system has bash in a different directory.

bash will almost certainly be needed after 'make install'. However, that 
does not mean

However, we need to be practical about this. It would require a huge 
effort to port  Sage to HP-UX or AIX due to numerous GNUism. I doubt 
more than a couple of the 100+ packages in Sage have ever been tested on 
AIX or HP-UX until I started to test some. I doubt we would ever 
distribute AIX or HP-UX binaries, but would expect people to build this 
on their own system from source.

> In any case, you should not use $foobar for both; if you need both, have
> two variables, which can default to the same thing.  And let your user
> know which is what, and how they can be overridden.
>
> > AC_CHECK_PROG(foobar,bash,[yes],[no],[])
> > if test x$foobar  != xyes
>
> The foobar variable will not be set to "yes" if bash is found anywhere,
> but to the command you can use to invoke bash.

Strange that, as it seemed to work. If I understand you correctly, 
(which I guess I am not), you are implying the script will not work at all.

I just modified it, so instead of search for bash, it searched for 
'fddfbash' which were just a few random letters I added in front of the 
command I was really looking for. The script seemed to have the desired 
effect, and reported it could not find 'fddfbash'

checking for bison... bison -y
checking for fddfbash... no
configure: WARNING: Sorry, the 'bash' shell is needed to build Sage
configure: WARNING: All modern systems will have the 'bash' shell 
installed somewhere
configure: WARNING: On HP-UX you may try adding /opt/OpenSource/bin/ to 
your path
configure: WARNING: On AIX you may try adding /opt/pware/bin to your path
configure: error: Exiting, as 'bash' was not found
 ERROR: You do not have all of the prerequisites needed
 to build Sage from source.  See the errors above.
make[1]: *** [installed/prereq-0.5] Error 1


> > As you can see, it offers suggestions of locations where 'bash' may
> > be found. Clearly, if the person is running on AIX, there is not
> > much point in telling them where to find bash on HP-UX.
>
> I don't think that is much of a problem.  Of course, you could be
> smarter, and run either of AC_CANONICAL_{BUILD,HOST} before and refine
> your suggestions based on $build or $host; but that's like icing the
> cake.

I already had one of AC_CANONICAL_BUILD or  AC_CANONICAL_BUILD, but now 
have both. How can I use them? On my HP-UX box, I now see in config.log

uname -s = HP-UX
ac_cv_build=hppa2.0w-hp-hpux11.11
ac_cv_host=hppa2.0w-hp-hpux11.11
build='hppa2.0w-hp-hpux11.11'
build_os='hpux11.11'
host='hppa2.0w-hp-hpux11.11'
host_os='hpux11.11'

I do not want to test for each individual release of HP-UX before giving 
a message. There must be hundreds of minor releases, and I've no idea 
what they are.

On my Solaris box, I see:

build='sparc-sun-solaris2.10'
build_os='solaris2.10'
host='sparc-sun-solaris2.10'
host_os='solaris2.10'

Again something with just 'solaris' would be useful. But there is some 
point in me having these, as I would like to do a test if the box is 
solaris 7, 8, or 9, and say it is unsupported. (Needless to say older 
version are not supported either. I assume one would give 
host_os='solaris2.5' and host_os='solaris2.6' on ancient systems, but 
anyone building Sage on such an old release would want their head tested.

Is there any way of just getting this as 'solaris' or just 'hpux' or 
'hp-ux' or 'aix' ?. Whilst I can see the point of have the version, I do 
not want to have to do a test for every version of AIX, just to decide 
what warning to give. I want a warning for any version of AIX, and any 
version of HP-UX, as both of them seem to have not have bash in the path 
 which a user might not expect. I've not no idea on very old Solaris 
systems, but all modern ones have it in /usr/bin. I do not have access 
to any machine with old versions of Solaris on, and can't be bothered to 
install it on a Sun just to find out where bash is, given we do not 
intend supporting Solaris versions of less than 10.

> Hope that helps.

Yes and no. I'm still confused about the best way to do this.

> Cheers,
> Ralf