unix: stop building _gdbm extension on 3.10

indygreg · indygreg · commit 25e3387ad66e · 2021-09-27T20:06:08.000-07:00
With the switch from readline to libedit, _gdbm was our final GPL
licensed dependency on Linux. In my opinion, the benefits of removing
the last GPL/copyleft license from the distributions outweighs the
benefits that the _gdbm extension provides.

If someone complains, we could potentially provide GPL versions
of the distributions containing readline and _gdbm. But until
someone asks, let's avoid the complexity.
diff --git a/cpython-unix/disabled-static-modules.3.10.linux64 b/cpython-unix/disabled-static-modules.3.10.linux64
@@ -0,0 +1,2 @@
+# We don't support GDBM because it is GPL v3.
+_gdbm
diff --git a/cpython-unix/static-modules.3.10.aarch64-unknown-linux-gnu b/cpython-unix/static-modules.3.10.aarch64-unknown-linux-gnu
@@ -12,7 +12,6 @@ _curses_panel _curses_panel.c -DHAVE_NCURSESW=1 -I/tools/deps/include/ncursesw -
 _dbm _dbmmodule.c -DHAVE_BERKDB_H -DDB_DBM_HSEARCH -I/tools/deps/include -L/tools/deps/lib -ldb
 _decimal _decimal/_decimal.c _decimal/libmpdec/basearith.c _decimal/libmpdec/constants.c _decimal/libmpdec/context.c _decimal/libmpdec/convolute.c _decimal/libmpdec/crt.c _decimal/libmpdec/difradix2.c _decimal/libmpdec/fnt.c _decimal/libmpdec/fourstep.c _decimal/libmpdec/io.c _decimal/libmpdec/mpalloc.c _decimal/libmpdec/mpdecimal.c _decimal/libmpdec/numbertheory.c _decimal/libmpdec/sixstep.c _decimal/libmpdec/transpose.c -DCONFIG_64=1 -DANSI=1 -DHAVE_UINT128_T=1 -IModules/_decimal/libmpdec
 _elementtree _elementtree.c -DHAVE_EXPAT_CONFIG_H=1 -DXML_POOR_ENTROPY=1 -DUSE_PYEXPAT_CAPI -IModules/expat
-_gdbm _gdbmmodule.c -DHAVE_NDBM_H -I/tools/deps/include -L/tools/deps/lib -lgdbm
 _hashlib _hashopenssl.c -I/tools/deps/include -L/tools/deps/lib -lcrypto
 _json _json.c
 _lsprof _lsprof.c rotatingtree.c
diff --git a/cpython-unix/static-modules.3.10.armv7-unknown-linux-gnueabi b/cpython-unix/static-modules.3.10.armv7-unknown-linux-gnueabi
@@ -12,7 +12,6 @@ _curses_panel _curses_panel.c -DHAVE_NCURSESW=1 -I/tools/deps/include/ncursesw -
 _dbm _dbmmodule.c -DHAVE_BERKDB_H -DDB_DBM_HSEARCH -I/tools/deps/include -L/tools/deps/lib -ldb
 _decimal _decimal/_decimal.c _decimal/libmpdec/basearith.c _decimal/libmpdec/constants.c _decimal/libmpdec/context.c _decimal/libmpdec/convolute.c _decimal/libmpdec/crt.c _decimal/libmpdec/difradix2.c _decimal/libmpdec/fnt.c _decimal/libmpdec/fourstep.c _decimal/libmpdec/io.c _decimal/libmpdec/mpalloc.c _decimal/libmpdec/mpdecimal.c _decimal/libmpdec/numbertheory.c _decimal/libmpdec/sixstep.c _decimal/libmpdec/transpose.c -DCONFIG_32=1 -DANSI=1 -IModules/_decimal/libmpdec
 _elementtree _elementtree.c -DHAVE_EXPAT_CONFIG_H=1 -DXML_POOR_ENTROPY=1 -DUSE_PYEXPAT_CAPI -IModules/expat
-_gdbm _gdbmmodule.c -DHAVE_NDBM_H -I/tools/deps/include -L/tools/deps/lib -lgdbm
 _hashlib _hashopenssl.c -I/tools/deps/include -L/tools/deps/lib -lcrypto
 _json _json.c
 _lsprof _lsprof.c rotatingtree.c
diff --git a/cpython-unix/static-modules.3.10.armv7-unknown-linux-gnueabihf b/cpython-unix/static-modules.3.10.armv7-unknown-linux-gnueabihf
@@ -12,7 +12,6 @@ _curses_panel _curses_panel.c -DHAVE_NCURSESW=1 -I/tools/deps/include/ncursesw -
 _dbm _dbmmodule.c -DHAVE_BERKDB_H -DDB_DBM_HSEARCH -I/tools/deps/include -L/tools/deps/lib -ldb
 _decimal _decimal/_decimal.c _decimal/libmpdec/basearith.c _decimal/libmpdec/constants.c _decimal/libmpdec/context.c _decimal/libmpdec/convolute.c _decimal/libmpdec/crt.c _decimal/libmpdec/difradix2.c _decimal/libmpdec/fnt.c _decimal/libmpdec/fourstep.c _decimal/libmpdec/io.c _decimal/libmpdec/mpalloc.c _decimal/libmpdec/mpdecimal.c _decimal/libmpdec/numbertheory.c _decimal/libmpdec/sixstep.c _decimal/libmpdec/transpose.c -DCONFIG_32=1 -DANSI=1 -IModules/_decimal/libmpdec
 _elementtree _elementtree.c -DHAVE_EXPAT_CONFIG_H=1 -DXML_POOR_ENTROPY=1 -DUSE_PYEXPAT_CAPI -IModules/expat
-_gdbm _gdbmmodule.c -DHAVE_NDBM_H -I/tools/deps/include -L/tools/deps/lib -lgdbm
 _hashlib _hashopenssl.c -I/tools/deps/include -L/tools/deps/lib -lcrypto
 _json _json.c
 _lsprof _lsprof.c rotatingtree.c
diff --git a/cpython-unix/static-modules.3.10.linux64 b/cpython-unix/static-modules.3.10.linux64
@@ -12,7 +12,6 @@ _ctypes_test _ctypes/_ctypes_test.c -lm
 _decimal _decimal/_decimal.c _decimal/libmpdec/basearith.c _decimal/libmpdec/constants.c _decimal/libmpdec/context.c _decimal/libmpdec/convolute.c _decimal/libmpdec/crt.c _decimal/libmpdec/difradix2.c _decimal/libmpdec/fnt.c _decimal/libmpdec/fourstep.c _decimal/libmpdec/io.c _decimal/libmpdec/mpalloc.c _decimal/libmpdec/mpdecimal.c _decimal/libmpdec/numbertheory.c _decimal/libmpdec/sixstep.c _decimal/libmpdec/transpose.c -DCONFIG_64=1 -DASM=1 -IModules/_decimal/libmpdec
 _dbm _dbmmodule.c -DHAVE_BERKDB_H -DDB_DBM_HSEARCH -I/tools/deps/include -L/tools/deps/lib -ldb
 _elementtree _elementtree.c -DHAVE_EXPAT_CONFIG_H=1 -DXML_POOR_ENTROPY=1 -DUSE_PYEXPAT_CAPI -IModules/expat
-_gdbm _gdbmmodule.c -DHAVE_NDBM_H -I/tools/deps/include -L/tools/deps/lib -lgdbm
 _hashlib _hashopenssl.c -I/tools/deps/include -L/tools/deps/lib -lcrypto
 _json _json.c
 _lsprof _lsprof.c rotatingtree.c
diff --git a/cpython-unix/static-modules.3.10.mips-unknown-linux-gnu b/cpython-unix/static-modules.3.10.mips-unknown-linux-gnu
@@ -12,7 +12,6 @@ _curses_panel _curses_panel.c -DHAVE_NCURSESW=1 -I/tools/deps/include/ncursesw -
 _dbm _dbmmodule.c -DHAVE_BERKDB_H -DDB_DBM_HSEARCH -I/tools/deps/include -L/tools/deps/lib -ldb
 _decimal _decimal/_decimal.c _decimal/libmpdec/basearith.c _decimal/libmpdec/constants.c _decimal/libmpdec/context.c _decimal/libmpdec/convolute.c _decimal/libmpdec/crt.c _decimal/libmpdec/difradix2.c _decimal/libmpdec/fnt.c _decimal/libmpdec/fourstep.c _decimal/libmpdec/io.c _decimal/libmpdec/mpalloc.c _decimal/libmpdec/mpdecimal.c _decimal/libmpdec/numbertheory.c _decimal/libmpdec/sixstep.c _decimal/libmpdec/transpose.c -DCONFIG_32=1 -DANSI=1 -IModules/_decimal/libmpdec
 _elementtree _elementtree.c -DHAVE_EXPAT_CONFIG_H=1 -DXML_POOR_ENTROPY=1 -DUSE_PYEXPAT_CAPI -IModules/expat
-_gdbm _gdbmmodule.c -DHAVE_NDBM_H -I/tools/deps/include -L/tools/deps/lib -lgdbm
 _hashlib _hashopenssl.c -I/tools/deps/include -L/tools/deps/lib -lcrypto
 _json _json.c
 _lsprof _lsprof.c rotatingtree.c
diff --git a/cpython-unix/static-modules.3.10.mipsel-unknown-linux-gnu b/cpython-unix/static-modules.3.10.mipsel-unknown-linux-gnu
@@ -12,7 +12,6 @@ _curses_panel _curses_panel.c -DHAVE_NCURSESW=1 -I/tools/deps/include/ncursesw -
 _dbm _dbmmodule.c -DHAVE_BERKDB_H -DDB_DBM_HSEARCH -I/tools/deps/include -L/tools/deps/lib -ldb
 _decimal _decimal/_decimal.c _decimal/libmpdec/basearith.c _decimal/libmpdec/constants.c _decimal/libmpdec/context.c _decimal/libmpdec/convolute.c _decimal/libmpdec/crt.c _decimal/libmpdec/difradix2.c _decimal/libmpdec/fnt.c _decimal/libmpdec/fourstep.c _decimal/libmpdec/io.c _decimal/libmpdec/mpalloc.c _decimal/libmpdec/mpdecimal.c _decimal/libmpdec/numbertheory.c _decimal/libmpdec/sixstep.c _decimal/libmpdec/transpose.c -DCONFIG_32=1 -DANSI=1 -IModules/_decimal/libmpdec
 _elementtree _elementtree.c -DHAVE_EXPAT_CONFIG_H=1 -DXML_POOR_ENTROPY=1 -DUSE_PYEXPAT_CAPI -IModules/expat
-_gdbm _gdbmmodule.c -DHAVE_NDBM_H -I/tools/deps/include -L/tools/deps/lib -lgdbm
 _hashlib _hashopenssl.c -I/tools/deps/include -L/tools/deps/lib -lcrypto
 _json _json.c
 _lsprof _lsprof.c rotatingtree.c
diff --git a/cpython-unix/static-modules.3.10.s390x-unknown-linux-gnu b/cpython-unix/static-modules.3.10.s390x-unknown-linux-gnu
@@ -12,7 +12,6 @@ _curses_panel _curses_panel.c -DHAVE_NCURSESW=1 -I/tools/deps/include/ncursesw -
 _dbm _dbmmodule.c -DHAVE_BERKDB_H -DDB_DBM_HSEARCH -I/tools/deps/include -L/tools/deps/lib -ldb
 _decimal _decimal/_decimal.c _decimal/libmpdec/basearith.c _decimal/libmpdec/constants.c _decimal/libmpdec/context.c _decimal/libmpdec/convolute.c _decimal/libmpdec/crt.c _decimal/libmpdec/difradix2.c _decimal/libmpdec/fnt.c _decimal/libmpdec/fourstep.c _decimal/libmpdec/io.c _decimal/libmpdec/mpalloc.c _decimal/libmpdec/mpdecimal.c _decimal/libmpdec/numbertheory.c _decimal/libmpdec/sixstep.c _decimal/libmpdec/transpose.c -DCONFIG_64=1 -DANSI=1 -DHAVE_UINT128_T=1 -IModules/_decimal/libmpdec
 _elementtree _elementtree.c -DHAVE_EXPAT_CONFIG_H=1 -DXML_POOR_ENTROPY=1 -DUSE_PYEXPAT_CAPI -IModules/expat
-_gdbm _gdbmmodule.c -DHAVE_NDBM_H -I/tools/deps/include -L/tools/deps/lib -lgdbm
 _hashlib _hashopenssl.c -I/tools/deps/include -L/tools/deps/lib -lcrypto
 _json _json.c
 _lsprof _lsprof.c rotatingtree.c
diff --git a/docs/running.rst b/docs/running.rst
@@ -92,7 +92,10 @@ Python and its various dependencies are governed by varied software use
 licenses. This impacts the rights and requirements of downstream consumers.
 
 Most licenses are fairly permissive. Notable exceptions to this are GDBM and
-readline, which are both licensed under GPL Version 3.
+readline, which are both licensed under GPL Version 3. Python 3.10 and
+newer distributions do not link against GDBM and readline and are not
+GPL encumbered. Older Python distributions may link against these libraries
+and may be subject to the GPL.
 
 **It is important to understand the licensing requirements when integrating
 the output of this project into derived works.** To help with this, the
diff --git a/docs/technotes.rst b/docs/technotes.rst
@@ -57,6 +57,9 @@ older are licensed under the Sleepycat License. The Sleepycat License
 is more permissive. So we build the ``_dbm`` extension against BDB
 6.0.19.
 
+We explicitly disable the ``_gdbm`` extension on all macOS versions
+and on Python 3.10+ Linux distributions to avoid the GPL dependency.
+
 readline / libedit / ncurses
 ----------------------------
 
diff --git a/pythonbuild/utils.py b/pythonbuild/utils.py
@@ -56,8 +56,9 @@ def target_needs(yaml_path: pathlib.Path, target: str, python_version: str):
     needs = set(settings["needs"])
 
     # We only ship libedit linked readline extension on 3.10+ to avoid a GPL
-    # dependency.
+    # dependency. Ditto for gdbm.
     if not python_version.startswith(("3.8", "3.9")):
+        needs.discard("gdbm")
         needs.discard("readline")
 
     return needs

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,2 @@`
	`1`	`+# We don't support GDBM because it is GPL v3.`
	`2`	`+_gdbm`