[GHC] #4900: DEPENDS pragma

[GHC]

#4900: DEPENDS pragma
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  Reporter:  cdsmith           |          Owner:                  
      Type:  feature request   |         Status:  patch           
  Priority:  normal            |      Milestone:  7.6.1           
 Component:  Build System      |        Version:                  
Resolution:                    |       Keywords:                  
        Os:  Unknown/Multiple  |   Architecture:  Unknown/Multiple
   Failure:  None/Unknown      |     Difficulty:  Unknown         
  Testcase:  TH_Depends        |      Blockedby:                  
  Blocking:                    |        Related:                  
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Changes (by parcs):

 * cc: patrick@… (added)
  * status:  new => patch


Comment:

 Hi,

 Currently this feature does not work with GHCi, as that has its own
 recompilation  checking for determining whether to pass a module down to
 the "standard" compilation pipeline.

 I have attached a patch that extends this feature to work GHCi, so that
 modules will be reloaded when their usage files have changed. Overview of
 changes:

  1. A field is added to ModSummary to keep track of the latest
 modification time of the module's usage files (`ms_uf_date`)
  2. When summarising a module/file, `ms_uf_date` is checked for freshness
 and updated if necessary.
  3. A module is now marked unstable if `ms_uf_date` is later than its
 'linkableTime'.

 Is this a reasonable solution?

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/4900#comment:43>
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