#9955: ghc-stage1 compiles with bootstrapping ghc package, not the built one -------------------------------------+------------------------------------- Reporter: ezyang | Owner: Type: bug | Status: new Priority: high | Milestone: 7.10.1 Component: Build System | Version: 7.11 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect result | Unknown/Multiple at runtime | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Revisions: -------------------------------------+------------------------------------- Changes (by ezyang): * priority: highest => high Comment: Falsified previous hypothesis. In fact, building GHC HEAD 7.10 works just fine; it's just the other way around that is a problem. Here's what's going on: When there are multiple wired in packages, we seem to ignore the hide-all- packages directive, and instead simply take all instances of the wired in package and *select the newest version*. Thus, when we compile GHC HEAD with GHC 7.10, the ghc package from GHC HEAD has a newer version than the system ghc package from 7.10, and we use that when compiling. However, when we build 7.10 with GHC HEAD, we always select the system GHC HEAD library, which works about as well as you'd expect. What is going on with the `--show-iface`? The key is that package dependency description is done by a lookup in the package database. The package key for 'ghc' is always ghc, no matter what the version is (since it's wired in), but I notably have NOT told ghc about the inplace package database in my show-iface command. So we lookup the package keyed 'ghc' in the default database, which is 7.10's, voila. This behavior sort of makes sense. In particular, it does make sense for GHC to try to output something besides a package key when referring to packages in debug output, because in general you don't necessarily care about the key in question, and the output is a lot more readable if you just get package name-version. The downside is it's easy to mess up wired in packages. It's possible #9652 is caused by the same underlying mechanism. My proposed fix for the wired in problem is to properly teach GHC to respect `-hide-all-packages -package wired-in-0.1.2`: we really SHOULD pick 0.1.2, even if there is a newer version. Of course, if we don't mention the wired in package, it probably makes sense to default back to the newest version. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9955#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#9955: ghc-stage1 compiles with bootstrapping ghc package, not the built one -------------------------------------+------------------------------------- Reporter: ezyang | Owner: Type: bug | Status: patch Priority: high | Milestone: 7.10.1 Component: Build System | Version: 7.11 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect result | Unknown/Multiple at runtime | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Revisions: Phab:D603 -------------------------------------+------------------------------------- Comment (by Edward Z. Yang ): In [changeset:"1f1595195443700b7c2708fa903969fa2f0a927b/ghc"]: {{{ #!CommitTicketReference repository="ghc" revision="1f1595195443700b7c2708fa903969fa2f0a927b" Respect package visibility when deciding wired in packages. Summary: Previously, we would consider ALL versions of a wired-in package, no matter if they were exposed or not, and pick the latest version. This patch is a minor refinement on the behavior: now we try to pick the wired in package from just the list of exposed packages, and if there are no candidates fall back on the full list. This means that if you do: -hide-all-packages -package wired-in-OLD-VERSION it will actually work by default (whereas previously you needed to *explicitly* -ignore-package the newer version). This is especially useful for the 'ghc' package. Fixes #9955. Signed-off-by: Edward Z. Yang Test Plan: validate Reviewers: simonpj, austin Reviewed By: austin Subscribers: carter, thomie Differential Revision: https://phabricator.haskell.org/D603 GHC Trac Issues: #9955 }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9955#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#9955: ghc-stage1 compiles with bootstrapping ghc package, not the built one -------------------------------------+------------------------------------- Reporter: ezyang | Owner: Type: bug | Status: closed Priority: high | Milestone: 7.10.1 Component: Build System | Version: 7.11 Resolution: fixed | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect result | Unknown/Multiple at runtime | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Revisions: Phab:D603 -------------------------------------+------------------------------------- Changes (by thoughtpolice): * status: merge => closed * resolution: => fixed Comment: Merged to `ghc-7.10` (via 57df7b312c408338401140474f5afc6951d49cf9). -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9955#comment:6 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler