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Description:

delocate 0.12.0

Delocate
macOS utilities to:

find dynamic libraries imported from python extensions
copy needed dynamic libraries to directory within package
update macOS install_names and rpath to cause code to load from copies
of libraries

Provides scripts:

delocate-listdeps – show libraries a tree depends on
delocate-path – copy libraries a tree depends on into the tree and relink
delocate-wheel – rewrite wheel having copied and relinked library
dependencies into the wheel tree.
delocate-merge – combine two wheels with different architectures into one
wheel with dual architecture binaries.

Auditwheel is a similar tool for Linux.
Auditwheel started life as a partial fork of Delocate.

The problem
Let’s say you have built a wheel somewhere, but it’s linking to dynamic
libraries elsewhere on the machine, so you can’t distribute it, because others
may not have these same libraries. Here we analyze the dependencies for
a Scipy wheel:
$ delocate-listdeps scipy-0.14.0b1-cp34-cp34m-macosx_10_6_intel.whl
/usr/local/Cellar/gfortran/4.8.2/gfortran/lib/libgcc_s.1.dylib
/usr/local/Cellar/gfortran/4.8.2/gfortran/lib/libgfortran.3.dylib
/usr/local/Cellar/gfortran/4.8.2/gfortran/lib/libquadmath.0.dylib
By default, this does not include libraries in /usr/lib and /System.
See those too with:
$ delocate-listdeps --all scipy-0.14.0-cp34-cp34m-macosx_10_6_intel.whl
/System/Library/Frameworks/Accelerate.framework/Versions/A/Accelerate
/usr/lib/libSystem.B.dylib
/usr/lib/libstdc++.6.dylib
/usr/local/Cellar/gfortran/4.8.2/gfortran/lib/libgcc_s.1.dylib
/usr/local/Cellar/gfortran/4.8.2/gfortran/lib/libgfortran.3.dylib
/usr/local/Cellar/gfortran/4.8.2/gfortran/lib/libquadmath.0.dylib
The output tells me that Scipy has picked up dynamic libraries from my
Homebrew installation of gfortran (as well as the system libs).
You can get a listing of the files depending on each of the libraries,
using the --depending flag:
$ delocate-listdeps --depending scipy-0.14.0-cp34-cp34m-macosx_10_6_intel.whl
/usr/local/Cellar/gfortran/4.8.2/gfortran/lib/libgcc_s.1.dylib:
scipy/interpolate/dfitpack.so
scipy/special/specfun.so
scipy/interpolate/_fitpack.so
...

A solution
We can fix like this:
$ delocate-wheel -w fixed_wheels -v scipy-0.14.0-cp34-cp34m-macosx_10_6_intel.whl
Fixing: scipy-0.14.0-cp34-cp34m-macosx_10_6_intel.whl
Copied to package .dylibs directory:
/usr/local/Cellar/gfortran/4.8.2/gfortran/lib/libgcc_s.1.dylib
/usr/local/Cellar/gfortran/4.8.2/gfortran/lib/libgfortran.3.dylib
/usr/local/Cellar/gfortran/4.8.2/gfortran/lib/libquadmath.0.dylib
The -w flag tells delocate-wheel to output to a new wheel directory
instead of overwriting the old wheel. -v (verbose) tells you what
delocate-wheel is doing. In this case it has made a new directory in the
wheel zipfile, named scipy/.dylibs. It has copied all the library
dependencies that are outside the macOS system trees into this directory, and
patched the python .so extensions in the wheel to use these copies instead
of looking in /usr/local/Cellar/gfortran/4.8.2/gfortran/lib.
Check the links again to confirm:
$ delocate-listdeps --all fixed_wheels/scipy-0.14.0-cp34-cp34m-macosx_10_6_intel.whl
/System/Library/Frameworks/Accelerate.framework/Versions/A/Accelerate
/usr/lib/libSystem.B.dylib
/usr/lib/libstdc++.6.0.9.dylib
@loader_path/../../../../.dylibs/libgcc_s.1.dylib
@loader_path/../../../../.dylibs/libgfortran.3.dylib
@loader_path/../../../../.dylibs/libquadmath.0.dylib
@loader_path/../../../.dylibs/libgcc_s.1.dylib
@loader_path/../../../.dylibs/libgfortran.3.dylib
@loader_path/../../../.dylibs/libquadmath.0.dylib
@loader_path/../../.dylibs/libgcc_s.1.dylib
@loader_path/../../.dylibs/libgfortran.3.dylib
@loader_path/../../.dylibs/libquadmath.0.dylib
@loader_path/../.dylibs/libgcc_s.1.dylib
@loader_path/../.dylibs/libgfortran.3.dylib
@loader_path/../.dylibs/libquadmath.0.dylib
@loader_path/libgcc_s.1.dylib
@loader_path/libquadmath.0.dylib
So - system dylibs the same, but the others moved into the wheel tree.
This makes the wheel more likely to work on another machine which does not have
the same version of Gfortran installed - in this example.

Checking required architectures
Current Python.org Python and the macOS system Python (/usr/bin/python)
are both dual architecture binaries. For example:
$ lipo -info /usr/bin/python
Architectures in the fat file: /usr/bin/python are: x86_64 arm64e
Note: you can compile ARM binaries for basic ARM (arm64), or to use
some extended ARM capabilities (arm64e) - see this SO post. Both
types of binaries work on Mac M1 and M2 machines, so we will use arm64 to
refer to either arm64 or arm64e.
The Big Sur macOS Python above has both x86_64 and arm64 (M1) versions
fused into one file. Earlier versions of macOS had dual architectures that
were 32-bit (i386) and 64-bit (x86_64).
For full compatibility with system and Python.org Python, wheels built for
Python.org Python or system Python should have the corresponding architectures
— e.g. x86_64 and arm64 versions of the Python extensions and their
libraries. It is easy to link Python extensions against single architecture
libraries by mistake, and therefore get single architecture extensions and /
or libraries. In fact my Scipy wheel is one such example, because I
inadvertently linked against the Homebrew libraries, which were x86_64
only. To check this you can use the --require-archs flag:
$ delocate-wheel --require-archs=intel scipy-0.14.0-cp34-cp34m-macosx_10_6_intel.whl
Traceback (most recent call last):
File "/Users/mb312/.virtualenvs/delocate/bin/delocate-wheel", line 77, in <module>
main()
File "/Users/mb312/.virtualenvs/delocate/bin/delocate-wheel", line 69, in main
check_verbose=opts.verbose)
File "/Users/mb312/.virtualenvs/delocate/lib/python2.7/site-packages/delocate/delocating.py", line 477, in delocate_wheel
"Some missing architectures in wheel")
delocate.delocating.DelocationError: Some missing architectures in wheel
Notice that this command was using an earlier version of Delocate that
supported Python 2; we now support Python 3 only.
The intel argument to --require-archs above requires dual 32- and 64-
bit architecture extensions and libraries. You can see which extensions are at
fault by adding the -v (verbose) flag:
$ delocate-wheel -w fixed_wheels --require-archs=intel -v scipy-0.14.0-cp34-cp34m-macosx_10_6_intel.whl
Fixing: scipy-0.14.0-cp34-cp34m-macosx_10_6_intel.whl
Required arch i386 missing from /usr/local/Cellar/gfortran/4.8.2/gfortran/lib/libgfortran.3.dylib
Required arch i386 missing from /usr/local/Cellar/gfortran/4.8.2/gfortran/lib/libquadmath.0.dylib
Required arch i386 missing from scipy/fftpack/_fftpack.so
Required arch i386 missing from scipy/fftpack/convolve.so
Required arch i386 missing from scipy/integrate/_dop.so
...
I need to rebuild this wheel to link with dual-architecture libraries.

Making dual-architecture binaries
Modern Mac wheels can be either arm64 (M1/M2 ARM), x86_64 (64-bit
Intel) or both (universal2).
Building an entire Python wheel as dual-architecture can be difficult, perhaps
because you need to link different libraries in the two cases, or you need
different compiler flags, or because you build for arm64 on one continuous
integration platform (such as - at time of writing - Cirrus CI), and x86_64
on another.
One solution to this problem is to do an entire arm64 wheel build, and then
an entire x86_64 wheel build, and fuse the two wheels into a universal
wheel.
That is what the delocate-merge command does.
Let’s say you have built an ARM and Intel wheel, called, respectively:

scipy-1.9.3-cp311-cp311-macosx_12_0_arm64.whl
scipy-1.9.3-cp311-cp311-macosx_10_9_x86_64.whl

Then you could create a new fused (universal2) wheel in the tmp
subdirectory with:
delocate-merge scipy-1.9.3-cp311-cp311-macosx_12_0_arm64.whl scipy-1.9.3-cp311-cp311-macosx_10_9_x86_64.whl -w tmp
The output wheel in that case would be:

tmp/scipy-1.9.3-cp311-cp311-macosx_12_0_universal2.whl

In the new wheel, you will find, using lipo -archs - that all binaries with
the same name in each wheel are now universal (x86_64 and arm64).

:warning: Note: In previous versions (<0.12.0) making dual architecture binaries was
performed with the delocate-fuse command. This commannd would overwrite the
first wheel passed in by default. This led to the user needing to rename the
wheel to correctly describe what platforms it supported. For this and other
reasons, wheels created with this were often incorrect. From version 0.12.0
and on, the delocate-fuse command has been removed and replaced with
delocate-merge. The delocate-merge command will create a new wheel with an
automatically generated name based on the wheels that were merged together.
There is no need to perform any further changes to the merged wheel’s name. If
the old behavior is needed (not recommended), pin the version to
delocate==0.11.0.

Troubleshooting
DelocationError: “library does not exist”
When running delocate-wheel or its sister command delocate-path, you
may get errors like this:
delocate.delocating.DelocationError: library "<long temporary path>/wheel/libme.dylib" does not exist
This happens when one of your libraries gives a library dependency with a
relative path. For example, let’s say that some file in my wheel has this for
the output of otool -L myext.so:
myext.so:
libme.dylib (compatibility version 10.0.0, current version 10.0.0)
/usr/lib/libstdc++.6.dylib (compatibility version 7.0.0, current version 60.0.0)
/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1197.1.1)
The first line means that myext.so expects to find libme.dylib at
exactly the path ./libme.dylib - the current working directory from which
you ran the executable. The output should be something like:
myext.so:
/path/to/libme.dylib (compatibility version 10.0.0, current version 10.0.0)
/usr/lib/libstdc++.6.dylib (compatibility version 7.0.0, current version 60.0.0)
/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1197.1.1)
To set the path to the library, the linker is using the install name id of
the linked library. In this bad case, then otool -L libme.dylib will give
something like:
libme.dylib (compatibility version 10.0.0, current version 10.0.0)
/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1197.1.1)
where the first line is the install name id that the linker picked up when
linking myext.so to libme.dylib. Your job is to fix the build process
so that libme.dylib has install name id /path/to/libme.dylib.
This is not a problem specific to Delocate; you will need to do this to
make sure that myext.so can load libme.dylib without libme.dylib
being in the current working directory. For CMAKE builds you may want to
check out CMAKE_INSTALL_NAME_DIR.

Code
See https://github.com/matthew-brett/delocate
Released under the BSD two-clause license - see the file LICENSE in the
source distribution.
GitHub Actions
kindly tests the code automatically.
The latest released version is at https://pypi.python.org/pypi/delocate

Support
Please put up issues on the Delocate issue tracker.