Opened 7 years ago

Closed 6 years ago

#3896 closed task (fixed)

Make the GHC build system accommodate extra packages

Reported by: simonpj Owned by:
Priority: normal Milestone: 7.0.1
Component: Build System Version:
Keywords: Cc:
Operating System: Unknown/Multiple Architecture: Unknown/Multiple
Type of failure: None/Unknown Test Case:
Blocked By: Blocking:
Related Tickets: Differential Rev(s):
Wiki Page:


Simon and I discussed the extra-packages story in GHC's build system. Here's a summary:

  • Simon added these 'extra-packages' stuff to help automate the process of downloading and building packages
    • that are not boot packages
    • but which we want to test regularly
  • DPH is another such package. It's not really a boot package, in the sense that (a) it's not necessary to build GHC and (b) it can only be built with a stage-2 compiler. The main reason it's treated as a boot package today is so that new patches are validated against it; it is a particularly good stress test. But it seems a bit overkill for it to masquerade as a boot package for that reason alone.
  • The current extra-packages story is a bit of a mess:
    • The extra packages are listed in $(TOP)/packages
    • But they are, quite separately listed in a make variable EXTRA_PACKAGES, and then stuffed into PACKAGES by 'addPackage' in $(TOP)/
    • A series of addPackage calls in duplicates the list of boot packages in $(TOP)/packages.
    • Moreover, the list in EXTRA_PACKAGES must be in dependency order.

We propose the following plan

  • Make the list in $(TOP)/packages the authoritative list.
  • Make 'sh boot' construct the list $(PACKAGES) from $(TOP)/packages and stuff it somewhere appropriate. ['sh boot' has to iterate over the packages anyhow, to boot them, but doesn't currently consult $(TOP)/packages to do so; it looks a the file system, which is less good.]
  • Make DPH into an extra package
  • And/or add a tag 'validated' to mean "this is an extra package, not a boot package, but it should be validated before pushing patches". That doesn't necessarily apply to all extra packages (eg stm).
  • The list in $(TOP)/packages is really a list of repositories not a list of packages. For example, utils/hcs2hs isn't a package. We probably want a tag ("util"?) to distinguish non-packages from packages.
  • DPH is unusual because it is a single repository that contains several packages. We can tell this because it has a file ghc-packages in its root directory, that lists the packages it contains. 'sh boot' must understand this when constructing $(PACKAGES); indeed it already does understand this.
  • Packages must be built in dependency order, and the build system has no way of figuring out the right order. But it would be easy to stipulate that $(TOP)/packages (and the ghc-packages file, if any, in the repo) should list the packages in dependency order.

We don't need to execute this plan right away, but would be a very nice clean-up if anyone felt up to doing something about it.

Change History (3)

comment:1 Changed 7 years ago by simonpj

Related to #3882

comment:2 Changed 7 years ago by igloo

Milestone: 6.14 branch6.14.1

comment:3 Changed 6 years ago by igloo

Resolution: fixed
Status: newclosed


Fri Sep 17 15:44:09 PDT 2010  Ian Lynagh <>
  * extra packages info is now read from packages file
  rather than being repeated in the build system
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