Retire the setup_requires hack in cases where it isn't needed (and can cause build problems). refs #2286

Signed-off-by: Daira Hopwood <daira@jacaranda.org>

NEWS.rst

@@ -121,6 +121,43 @@ of the 1.10.0 release:
   the directory itself", the tool creates "./local/missing/dir/file.txt".
 
 
+Compatibility and Dependency Updates
+------------------------------------
+
+- Twisted >= 13.0.0
+- Nevow >= 0.11.1
+- foolscap >= 0.8.0
+- service-identity
+- characteristic >= 14.0.0
+- pyasn1 >= 0.1.4
+- pyasn1-modules >= 0.0.5
+
+On Windows, if pywin32 is not installed then the dependencies on Twisted
+and Nevow become:
+
+- Twisted >= 11.1.0, <= 12.1.0
+- Nevow >= 0.9.33, <= 0.10
+
+On all platforms, if pyOpenSSL >= 0.14 is installed, then it will be used,
+but if not then only pyOpenSSL >= 0.13, <= 0.13.1 will be built when directly
+invoking `setup.py build` or `setup.py install`.
+
+We strongly advise OS packagers to take the option of making a tahoe-lafs
+package depend on pyOpenSSL >= 0.14. In order for that to work, the following
+additional Python dependencies are needed:
+
+- cryptography
+- cffi >= 0.8
+- six >= 1.4.1
+- enum34
+- pycparser
+
+as well as libffi (for Debian/Ubuntu, the name of the needed OS package is
+`libffi6`).
+
+Tahoe-LAFS is now compatible with setuptools version 8 and pip version 6
+or later.
+
 
 Release 1.10.0 (2013-05-01)
 '''''''''''''''''''''''''''

setup.py

@@ -64,6 +64,7 @@ else:
 adglobals = {}
 execfile('src/allmydata/_auto_deps.py', adglobals)
 install_requires = adglobals['install_requires']
+setup_requires = adglobals['setup_requires']
 
 if len(sys.argv) > 1 and sys.argv[1] == '--fakedependency':
     del sys.argv[1]
@@ -113,23 +114,6 @@ trove_classifiers=[
     ]
 
 
-setup_requires = []
-
-# Nevow imports itself when building, which causes Twisted and zope.interface
-# to be imported. We need to make sure that the versions of Twisted and
-# zope.interface used at build time satisfy Nevow's requirements. If not
-# then there are two problems:
-#  - prior to Nevow v0.9.33, Nevow didn't declare its dependency on Twisted
-#    in a way that enabled setuptools to satisfy that requirement at
-#    build time.
-#  - some versions of zope.interface, e.g. v3.6.4, are incompatible with
-#    Nevow, and we need to avoid those both at build and run-time.
-#
-# This only matters when compatible versions of Twisted and zope.interface
-# are not already installed. Retire this hack when
-# https://bugs.launchpad.net/nevow/+bug/812537 has been fixed.
-setup_requires += [req for req in install_requires if req.startswith('Twisted') or req.startswith('zope.interface')]
-
 # We no longer have any requirements specific to tests.
 tests_require=[]
 

src/allmydata/_auto_deps.py

@@ -106,49 +106,58 @@ if not hasattr(sys, 'frozen'):
     package_imports.append(('setuptools', 'setuptools'))
 
 
-# Splitting the dependencies for Windows and non-Windows helps to fix
-# <https://tahoe-lafs.org/trac/tahoe-lafs/ticket/2249> and
-# <https://tahoe-lafs.org/trac/tahoe-lafs/ticket/2028>.
+# * On Linux we need at least Twisted 10.1.0 for inotify support
+#   used by the drop-upload frontend.
+# * We also need Twisted 10.1.0 for the FTP frontend in order for
+#   Twisted's FTP server to support asynchronous close.
+# * The SFTP frontend depends on Twisted 11.0.0 to fix the SSH server
+#   rekeying bug <https://twistedmatrix.com/trac/ticket/4395>
+# * The FTP frontend depends on Twisted >= 11.1.0 for
+#   filepath.Permissions
+#
+# On Windows, Twisted >= 12.2.0 has a dependency on pywin32.
+# Since pywin32 can only be installed manually, we fall back to
+# requiring earlier versions of Twisted and Nevow if it is not
+# already installed.
+# <https://tahoe-lafs.org/trac/tahoe-lafs/ticket/2028>
+#
+# When the fallback is used we also need to work around the fact
+# that Nevow imports itself when building, which causes Twisted
+# and zope.interface to be imported; therefore, we need to set
+# setup_requires to make sure that the versions of Twisted and
+# zope.interface used at build time satisfy Nevow's requirements.
+#
+# In cases where this fallback isn't needed, we prefer Nevow >= 0.11.1
+# which can be installed using pip, and Twisted >= 13.0.0 which
+# Nevow 0.11.1 depends on. In this case we should *not* use the
+# setup_requires hack, because if we do then the build will break
+# when Twisted < 13.0.0 is already installed (even though it could
+# have succeeded by building a later version under support/ ).
+#
+# <https://tahoe-lafs.org/trac/tahoe-lafs/ticket/2032>
+# <https://tahoe-lafs.org/trac/tahoe-lafs/ticket/2249>
+# <https://tahoe-lafs.org/trac/tahoe-lafs/ticket/2291>
+# <https://tahoe-lafs.org/trac/tahoe-lafs/ticket/2286>
 
+setup_requires = []
+
+_use_old_Twisted_and_Nevow = False
 if sys.platform == "win32":
-    install_requires += [
-        # * On Windows we need at least Twisted 9.0 to avoid an indirect
-        #   dependency on pywin32.
-        # * We also need Twisted 10.1 for the FTP frontend in order for
-        #   Twisted's FTP server to support asynchronous close.
-        # * When the cloud backend lands, it will depend on Twisted 10.2.0
-        #   which includes the fix to <https://twistedmatrix.com/trac/ticket/411>.
-        # * The SFTP frontend depends on Twisted 11.0.0 to fix the SSH server
-        #   rekeying bug <https://twistedmatrix.com/trac/ticket/4395>
-        # * The FTP frontend depends on Twisted >=11.1.0 for
-        #   filepath.Permissions
-        # * We don't want Twisted >= 12.2.0 to avoid a dependency of its endpoints
-        #   code on pywin32. <https://tahoe-lafs.org/trac/tahoe-lafs/ticket/2028>
-        #
-        "Twisted >= 11.1.0, <= 12.1.0",
+    try:
+        import win32api
+    except ImportError:
+        _use_old_Twisted_and_Nevow = True
 
-        # * We need Nevow >= 0.9.33 to avoid a bug in Nevow's setup.py
-        #   which imported twisted at setup time.
-        # * We don't want Nevow 0.11 because that requires Twisted >= 13.0
-        #   which conflicts with the Twisted requirement above.
-        #   <https://tahoe-lafs.org/trac/tahoe-lafs/ticket/2291>
-        #
+if _use_old_Twisted_and_Nevow:
+    install_requires += [
+        "Twisted >= 11.1.0, <= 12.1.0",
         "Nevow >= 0.9.33, <= 0.10",
     ]
+    setup_requires += [req for req in install_requires if req.startswith('Twisted')
+                                                       or req.startswith('zope.interface')]
 else:
     install_requires += [
-        # * On Linux we need at least Twisted 10.1.0 for inotify support
-        #   used by the drop-upload frontend.
-        # * Nevow 0.11.1 requires Twisted >= 13.0.0 so we might as well
-        #   require it directly; this helps to work around
-        #   <https://tahoe-lafs.org/trac/tahoe-lafs/ticket/2286>.
-        #   This also satisfies the requirements for the FTP and SFTP
-        #   frontends and cloud backend mentioned in the Windows section
-        #   above.
-        #
         "Twisted >= 13.0.0",
-
-        # Nevow >= 0.11.1 can be installed using pip.
         "Nevow >= 0.11.1",
     ]