bpo-36302: Sort list of sources (pythonGH-12341)

When building packages (e.g. for openSUSE Linux) (random) filesystem order of input files influences ordering of functions in the output .so files. Thus without the patch, builds (in disposable VMs) would usually differ. Without this patch, all callers have to be patched individually ofalk/libdnet#42 sass/libsass-python#212 tahoe-lafs/pycryptopp#41 yt-project/yt#2206 pyproj4/pyproj#142 pytries/datrie#49 Roche/pyreadstat#37 but that is an infinite effort. See https://reproducible-builds.org/ for why this matters.
DinoV · Jan 14, 2020 · ff1dab2 · ff1dab2
1 parent e6da8ee
commit ff1dab2
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diff --git a/Lib/distutils/command/build_ext.py b/Lib/distutils/command/build_ext.py
@@ -490,7 +490,8 @@ def build_extension(self, ext):
                   "in 'ext_modules' option (extension '%s'), "
                   "'sources' must be present and must be "
                   "a list of source filenames" % ext.name)
-        sources = list(sources)
+        # sort to make the resulting .so file build reproducible
+        sources = sorted(sources)
 
         ext_path = self.get_ext_fullpath(ext.name)
         depends = sources + ext.depends

diff --git a/Misc/NEWS.d/next/Library/2019-03-21-19-23-46.bpo-36302.Yc591g.rst b/Misc/NEWS.d/next/Library/2019-03-21-19-23-46.bpo-36302.Yc591g.rst
@@ -0,0 +1,2 @@
+distutils sorts source file lists so that Extension .so files
+build more reproducibly by default
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,2 @@
		distutils sorts source file lists so that Extension .so files
		build more reproducibly by default