setup: use execfile to access _auto_deps.py in its proper location of src/allmydata/ instead of copying it into place when setup.py is executed

Makefile

@@ -243,10 +243,10 @@ test-darcs-boringfile:
 	$(PYTHON) misc/build_helpers/test-darcs-boringfile.py
 
 test-clean:
-	find . |grep -vEe "_darcs|allfiles.tmp|src/allmydata/_(version|auto_deps|appname).py" |sort >allfiles.tmp.old
+	find . |grep -vEe "_darcs|allfiles.tmp|src/allmydata/_(version|appname).py" |sort >allfiles.tmp.old
 	$(MAKE)
 	$(MAKE) clean
-	find . |grep -vEe "_darcs|allfiles.tmp|src/allmydata/_(version|auto_deps|appname).py" |sort >allfiles.tmp.new
+	find . |grep -vEe "_darcs|allfiles.tmp|src/allmydata/_(version|appname).py" |sort >allfiles.tmp.new
 	diff allfiles.tmp.old allfiles.tmp.new
 
 clean:

setup.py

@@ -48,11 +48,6 @@ from setuptools import find_packages, setup
 from setuptools.command import sdist
 from setuptools import Command
 
-# Make the dependency-version-requirement, which is used by the Makefile at
-# build-time, also available to the app at runtime:
-shutil.copyfile("_auto_deps.py",
-                os.path.join("src", "allmydata", "_auto_deps.py"))
-
 trove_classifiers=[
     "Development Status :: 5 - Production/Stable",
     "Environment :: Console",
@@ -224,8 +219,9 @@ class CheckAutoDeps(Command):
     def finalize_options(self):
         pass
     def run(self):
-        import _auto_deps
-        _auto_deps.require_auto_deps()
+        adglobals = {}
+        execfile('src/allmydata/_auto_deps.py', adglobals)
+        adglobals['require_auto_deps']()
 
 
 class MakeExecutable(Command):
@@ -326,7 +322,9 @@ class MySdist(sdist.sdist):
 # Tahoe's dependencies are managed by the find_links= entry in setup.cfg and
 # the _auto_deps.install_requires list, which is used in the call to setup()
 # below.
-from _auto_deps import install_requires
+adglobals = {}
+execfile('src/allmydata/_auto_deps.py', adglobals)
+install_requires = adglobals['install_requires']
 
 APPNAME='allmydata-tahoe'
 APPNAMEFILE = os.path.join('src', 'allmydata', '_appname.py')

src/allmydata/_auto_deps.py

@@ -1,3 +1,10 @@
+# Note: do not import any module from Tahoe-LAFS itself in this
+# file. Also please avoid importing modules from other packages than
+# the Python Standard Library if at all possible (exception: we rely
+# on importing pkg_resources, which is provided by setuptools,
+# zetuptoolz, distribute, and perhaps in the future distutils2, for
+# the require_auto_deps() function.)
+
 install_requires=[
                   # we require newer versions of setuptools (actually
                   # zetuptoolz) to build, but can handle older versions to run
@@ -64,6 +71,7 @@ if sys.version_info < (2, 5):
 
 if hasattr(sys, 'frozen'): # for py2exe
     install_requires=[]
+del sys # clean up namespace
 
 def require_python_version():
     import sys, platform