[commit: ghc] master: sphinx-build: fix python stack overflow (Trac #10950) (4c11db6)

[git at git.haskell.org]

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

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/4c11db6377aa4fba0c4d70a1e9508247fd053bce/ghc

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

commit 4c11db6377aa4fba0c4d70a1e9508247fd053bce
Author: Sergei Trofimovich <slyfox at gentoo.org>
Date:   Thu Jan 21 21:43:37 2016 +0000

    sphinx-build: fix python stack overflow (Trac #10950)
    
    Summary:
    commit a034031a102bc08c76a6cdb104b72922ae22c96b did not
    fix problem completely. Stack overflows still occasionally
    happen.
    
    Easy to test by the following Torture Test:
    
      while sphinx-build -T -N -E -a -b html \
            -d docs/users_guide/.doctrees-html \
            -D latex_paper_size=letter \
            docs/users_guide docs/users_guide/build-html/users_guide
      do
        echo again
      done
    
    sphinx build large nested data structures when parses GHC manual
    (docs/users_guide/glasgow_exts.rst is 455KB in size) which
    can't be serialized useing default python call stack depth of 1000
    calls.
    
    The patch increases stack depth 10 times. Survived 2 hours of
    Torture Test.
    
    Signed-off-by: Sergei Trofimovich <siarheit at google.com>
    
    Test Plan: ran Torture Test to make sure it is stable
    
    Reviewers: austin, bgamari
    
    Reviewed By: bgamari
    
    Subscribers: thomie
    
    Differential Revision: https://phabricator.haskell.org/D1809
    
    GHC Trac Issues: #10950


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

4c11db6377aa4fba0c4d70a1e9508247fd053bce
 docs/users_guide/conf.py | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/docs/users_guide/conf.py b/docs/users_guide/conf.py
index 119223a..f9c326e 100644
--- a/docs/users_guide/conf.py
+++ b/docs/users_guide/conf.py
@@ -147,6 +147,8 @@ def parse_flag(env, sig, signode):
 def setup(app):
     from sphinx.util.docfields import Field, TypedField
 
+    increase_python_stack()
+
     # the :ghci-cmd: directive used in ghci.rst
     app.add_object_type('ghci-cmd', 'ghci-cmd',
                         parse_node=parse_ghci_cmd,
@@ -171,3 +173,11 @@ def setup(app):
                             Field('since', label='Introduced in GHC version', names=['since']),
                             Field('static')
                         ])
+
+def increase_python_stack():
+    # Workaround sphinx-build recursion limit overflow:
+    # pickle.dump(doctree, f, pickle.HIGHEST_PROTOCOL)
+    #  RuntimeError: maximum recursion depth exceeded while pickling an object
+    #
+    # Default python allows recursion depth of 1000 calls.
+    sys.setrecursionlimit(10000)