[commit: ghc] master: Fix recompilation detection when set of signatures to merge changes. (db23ccf)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/db23ccfa2016902301a2fe71dedc2d6d3f3427be/ghc

>---------------------------------------------------------------

commit db23ccfa2016902301a2fe71dedc2d6d3f3427be
Author: Edward Z. Yang <ezyang at cs.stanford.edu>
Date:   Sun Dec 11 19:42:29 2016 -0800

    Fix recompilation detection when set of signatures to merge changes.
    
    Summary:
    Previously, we only checked to recompile if a signature we
    previously depended on changed; however, if the -unit-id
    settings changed, this could have resulted in more or less
    signatures needing to be merged in; we weren't checking
    for this case.
    
    (Note that this logic is irrelevant for normal module imports,
    which we also check using -unit-id, as we record each import
    and redo it, forcing a recompile if the result changed.)
    
    Signed-off-by: Edward Z. Yang <ezyang at cs.stanford.edu>
    
    Test Plan: validate
    
    Reviewers: simonpj, austin, bgamari
    
    Subscribers: thomie
    
    Differential Revision: https://phabricator.haskell.org/D2832


>---------------------------------------------------------------

db23ccfa2016902301a2fe71dedc2d6d3f3427be
 compiler/basicTypes/Module.hs                      | 22 +++++++++++++
 compiler/iface/MkIface.hs                          | 19 +++++++++++-
 testsuite/driver/extra_files.py                    |  1 +
 .../tests/backpack/cabal/bkpcabal03/.gitignore     |  1 +
 testsuite/tests/backpack/cabal/bkpcabal03/Makefile | 36 ++++++++++++++++++++++
 testsuite/tests/backpack/cabal/bkpcabal03/Mod.hs   |  4 +++
 .../cabal/{bkpcabal01 => bkpcabal03}/Setup.hs      |  0
 .../T12733 => backpack/cabal/bkpcabal03}/all.T     |  4 +--
 .../tests/backpack/cabal/bkpcabal03/asig1/A.hsig   |  2 ++
 .../backpack/cabal/bkpcabal03/asig1/asig1.cabal    | 12 ++++++++
 .../tests/backpack/cabal/bkpcabal03/asig2/A.hsig   |  2 ++
 .../backpack/cabal/bkpcabal03/asig2/asig2.cabal    | 12 ++++++++
 .../backpack/cabal/bkpcabal03/bkpcabal03.cabal.in1 | 12 ++++++++
 .../backpack/cabal/bkpcabal03/bkpcabal03.cabal.in2 | 12 ++++++++
 .../backpack/cabal/bkpcabal03/bkpcabal03.stderr    |  2 ++
 15 files changed, 138 insertions(+), 3 deletions(-)

Diff suppressed because of size. To see it, use:

    git diff-tree --root --patch-with-stat --no-color --find-copies-harder --ignore-space-at-eol --cc db23ccfa2016902301a2fe71dedc2d6d3f3427be