[GHC] #15538: GHC boot script can't handle Git origin not named origin

[GHC]

#15538: GHC boot script can't handle Git origin not named origin
-------------------------------------+-------------------------------------
           Reporter:  ChaiTRex       |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:  8.6.1
          Component:  Build System   |           Version:
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  Building GHC
  Unknown/Multiple                   |  failed
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
-------------------------------------+-------------------------------------
 == Problem

 I ran the following to get the sources for GHC to build them:

 {{{
 git clone -o ghc --recursive http://git.haskell.org/ghc.git
 }}}

 Note especially the `-o ghc` part, which uses the Git origin name `ghc`
 instead of the default `origin`. When a custom origin name is used,
 `./boot` fails:

 {{{
 $ ./boot
 Traceback (most recent call last):
   File "./boot", line 193, in <module>
     check_for_url_rewrites()
   File "./boot", line 29, in check_for_url_rewrites
     subprocess.check_output('git config
 remote.origin.url'.split()).find(b'github.com') != -1 and \
   File "/usr/lib/python3.5/subprocess.py", line 626, in check_output
     **kwargs).stdout
   File "/usr/lib/python3.5/subprocess.py", line 708, in run
     output=stdout, stderr=stderr)
 subprocess.CalledProcessError: Command '['git', 'config',
 'remote.origin.url']' returned non-zero exit status 1

 $ git config remote.origin.url

 $ echo $?
 1
 }}}

 == Solution

 To get the URL of the proper origin name, `git config
 branch.master.remote` can be used to get the origin name to use to get the
 URL:

 {{{
 $ git config "remote.$( git config branch.master.remote ).url"
 http://git.haskell.org/ghc.git
 }}}

 == Workaround

 Rename the origin to `origin`:

 {{{
 $ git remote rename "$( git config branch.master.remote )" origin
 $ ./boot
 Creating libraries/mtl/ghc.mk
 Creating libraries/unix/ghc.mk
 Creating libraries/text/ghc.mk
 ⋮
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15538>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler