[opam-devel] [ocaml-platform] A small script for compiler hackers: create short-lived opam switches out of any git branch

Anil Madhavapeddy anil at recoil.org
Tue Mar 19 14:26:23 GMT 2013

Yeah.  Is there any reason not to distribute your script with OPAM in a 
contrib/ directory btw?  It would be good to keep these in one place
just to make testing easier.


On 18 Mar 2013, at 13:03, Gabriel Scherer <gabriel.scherer at gmail.com> wrote:

> I think my approach and the "patch" feature fulfill different needs:
> the point here is that opam does *not* recompile the sources when
> installing the switch. If you only provide an archive and a patch,
> opam will have to recompile the sources.
> I see my script as useful locally for compiler hackers (make
> world.opt, hack a bit, make all to recompile only what's changed, opam
> install & test, hack a bit, make all, opam install & test).
> On the other side, the "patch" feature is useful if you want to
> distribute your patches to less savvy users ("check my new
> optimization patchset against your own programs", BER-MetaOCaml,
> etc...).
> On Mon, Mar 18, 2013 at 5:41 PM, Wojciech Meyer
> <wojciech.meyer at gmail.com> wrote:
>> So the idea here was to use command line to quick apply patches and
>> test the integrity them after reviewing, but do this in such way I am
>> not forced to make the tree full of diffs.
>> On other hand maybe Gabriel idea scales better, I agree as we want to
>> commit them eventually.
>> The idea came to my mind after struggling with testing my patches and
>> trying out ocamlbuild on OPAM repo which I did but saying just "make
>> world.opt opt.opt install".
>> So probably the shell script takes precedence.
>> On Mon, Mar 18, 2013 at 4:13 PM, Anil Madhavapeddy <anil at recoil.org> wrote:
>>> On 17 Mar 2013, at 14:18, Wojciech Meyer <wojciech.meyer at gmail.com> wrote:
>>>> Hi Gabriel,
>>>> all is needed for testing ocamlbuild and local patches for the compiler,
>>>> thank you.
>>>> Other useful thing in general for OPAM would be something like:
>>>> opam patch add <ordered list_of_patches>
>>>> opam patch reset
>>>> then we are able quickly test some local patches without touching
>>>> command line and invoking makefiles.
>>> Just to clarify this, are you asking for this for the compiler switches,
>>> or for packages, or for both?
>>> Local patches can be made to work with packages via `opam pin`, although
>>> supporting a patch queue model may be useful in the future.
>>> Compiler patches don't exist at the moment within OPAM, but I like Gabriel's
>>> approach of taking an existing tree (that's, e.g., a git repo) and moving
>>> it into the OPAM space.  You can just use the underlying VCS to track your
>>> patches and branches without requiring more complexity in OPAM.
>>> -anil
>>>> Gabriel Scherer <gabriel.scherer at gmail.com> writes:
>>>>> As part of the slowly-evolving benchmark work, I have developed a
>>>>> script to turn any repository that quacks like an OCaml compiler and
>>>>> can run "make world.opt" into an OPAM compiler switch.
>>>>> https://github.com/gasche/opam-compiler-conf
>>>>> The intended use case is to change something, recompile what need be,
>>>>> get a compiler switch for that, and install one or two packages for
>>>>> testing something. You could envision, for example, OPAM being used in
>>>>> the internal loop of a bisection process. In this case it is important
>>>>> that OPAM does not recompile the compiler on its side (so the usual
>>>>> technique of making a tarball of the compiler source and letting OPAM
>>>>> do its job from there is not pleasant in that situation); the scripts
>>>>> makes use of voodoo OPAM compiler options (thanks to Thomas in
>>>>> https://github.com/OCamlPro/opam/pull/519 ) to have it just run "make
>>>>> install" each time "opam switch reinstall" is called.
>>>>> This is a quick&dirty shell script that works on my machine. No
>>>>> guarantee that it will work on yours. It also assumes that the
>>>>> version-control system (VCS) used is git, and calls "git branch" to
>>>>> infer the name of the compiler switch to use. Eventual patches to
>>>>> support other VCSs (or, for example, infer the switch name from the
>>>>> directory name) would be welcome.
>>>> _______________________________________________
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>>>> Platform at lists.ocaml.org
>>>> http://lists.ocaml.org/listinfo/platform

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