BUG: Avoid compilation error of wrapper file generated with SWIG >= 4.4 #30128
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
The `import_array` macro, which is defined in the file `numpy/core/code_generators/generate_numpy_api.py`, is intended for use inside an internal SWIG function that is called in the generated C wrapper file. This macro contains a return statement whose argument must match the function definition. Until version 4.3 of SWIG, the aforementioned function returned a `void*` value. However, in version 4.4, the return value was changed to `int`. This causes compilation of code using import_array() to fail with the following error message: `returning 'void *' from a function with return type 'int' makes integer from pointer without a cast [-Wint-conversion].` This commit resolves the issue by returning either `NULL` or `0`, depending on the SWIG version being used (< 3.4 or >= 3.4, respectively). This change has been successfully tested against SWIG versions 4.3 and 4.4. Closes: numpy#30122
Member
|
As mentioned in the issue, we don't really hit this code in our tests (which is why we missed it in the first place). Could you suggest a meson-based small code sample that uses SWIG? Then we can try to incorporate this into the Using Python as glue guide, and make it run in C to test it for bitrot. |
Member
|
The example idea can be in a separate PR if you wish, this one should be good to go. |
Contributor
Author
My knowledge of meson is virtually nonexistent. Could you direct me to a relevant example in the NumPy source code that could serve as a template for the proposed SWIG test? |
Member
|
Thanks @rlaboiss . Let's get this in and leave an example test for another PR. |
Contributor
Author
|
Thanks for merging the PR. I just noticed that the bug can be triggered in NumPy's current source, with SWIG 4.4. installed in the system $ swig --version | grep Version
SWIG Version 4.4.0
$ cd tools/swig/test/
$ make
swig -c++ -python Array.i
swig -c++ -python Farray.i
swig -c++ -python Vector.i
swig -c++ -python Matrix.i
swig -c++ -python Tensor.i
swig -c++ -python Fortran.i
swig -c++ -python Flat.i
./setup.py build_ext -i
Array_wrap.cxx: In function ‘int SWIG_mod_exec(PyObject*)’:
Array_wrap.cxx:8533:3: warning: converting to non-pointer type ‘int’ from NULL [-Wconversion-null]
8533 | import_array();
| ^~~~~~~~~~~~
Farray_wrap.cxx: In function ‘int SWIG_mod_exec(PyObject*)’:
Farray_wrap.cxx:6485:3: warning: converting to non-pointer type ‘int’ from NULL [-Wconversion-null]
6485 | import_array();
| ^~~~~~~~~~~~
Vector_wrap.cxx: In function ‘int SWIG_mod_exec(PyObject*)’:
Vector_wrap.cxx:9405:3: warning: converting to non-pointer type ‘int’ from NULL [-Wconversion-null]
9405 | import_array();
| ^~~~~~~~~~~~
Matrix_wrap.cxx: In function ‘int SWIG_mod_exec(PyObject*)’:
Matrix_wrap.cxx:9028:3: warning: converting to non-pointer type ‘int’ from NULL [-Wconversion-null]
9028 | import_array();
| ^~~~~~~~~~~~
Tensor_wrap.cxx: In function ‘int SWIG_mod_exec(PyObject*)’:
Tensor_wrap.cxx:9112:3: warning: converting to non-pointer type ‘int’ from NULL [-Wconversion-null]
9112 | import_array();
| ^~~~~~~~~~~~
Fortran_wrap.cxx: In function ‘int SWIG_mod_exec(PyObject*)’:
Fortran_wrap.cxx:5414:3: warning: converting to non-pointer type ‘int’ from NULL [-Wconversion-null]
5414 | import_array();
| ^~~~~~~~~~~~
Flat_wrap.cxx: In function ‘int SWIG_mod_exec(PyObject*)’:
Flat_wrap.cxx:5088:3: warning: converting to non-pointer type ‘int’ from NULL [-Wconversion-null]
5088 | import_array();
| ^~~~~~~~~~~~ |
charris
pushed a commit
to charris/numpy
that referenced
this pull request
Nov 3, 2025
….4 (numpy#30128) The `import_array` macro, which is defined in the file `numpy/core/code_generators/generate_numpy_api.py`, is intended for use inside an internal SWIG function that is called in the generated C wrapper file. This macro contains a return statement whose argument must match the function definition. Until version 4.3 of SWIG, the aforementioned function returned a `void*` value. However, in version 4.4, the return value was changed to `int`. This causes compilation of code using import_array() to fail with the following error message: `returning 'void *' from a function with return type 'int' makes integer from pointer without a cast [-Wint-conversion].` This commit resolves the issue by returning either `NULL` or `0`, depending on the SWIG version being used (< 3.4 or >= 3.4, respectively). This change has been successfully tested against SWIG versions 4.3 and 4.4. Closes: numpy#30122
charris
added a commit
that referenced
this pull request
Nov 3, 2025
BUG: Avoid compilation error of wrapper file generated with SWIG >= 4.4 (#30128)
cakedev0
pushed a commit
to cakedev0/numpy
that referenced
this pull request
Dec 5, 2025
….4 (numpy#30128) The `import_array` macro, which is defined in the file `numpy/core/code_generators/generate_numpy_api.py`, is intended for use inside an internal SWIG function that is called in the generated C wrapper file. This macro contains a return statement whose argument must match the function definition. Until version 4.3 of SWIG, the aforementioned function returned a `void*` value. However, in version 4.4, the return value was changed to `int`. This causes compilation of code using import_array() to fail with the following error message: `returning 'void *' from a function with return type 'int' makes integer from pointer without a cast [-Wint-conversion].` This commit resolves the issue by returning either `NULL` or `0`, depending on the SWIG version being used (< 3.4 or >= 3.4, respectively). This change has been successfully tested against SWIG versions 4.3 and 4.4. Closes: numpy#30122
IndifferentArea
pushed a commit
to IndifferentArea/numpy
that referenced
this pull request
Dec 7, 2025
….4 (numpy#30128) The `import_array` macro, which is defined in the file `numpy/core/code_generators/generate_numpy_api.py`, is intended for use inside an internal SWIG function that is called in the generated C wrapper file. This macro contains a return statement whose argument must match the function definition. Until version 4.3 of SWIG, the aforementioned function returned a `void*` value. However, in version 4.4, the return value was changed to `int`. This causes compilation of code using import_array() to fail with the following error message: `returning 'void *' from a function with return type 'int' makes integer from pointer without a cast [-Wint-conversion].` This commit resolves the issue by returning either `NULL` or `0`, depending on the SWIG version being used (< 3.4 or >= 3.4, respectively). This change has been successfully tested against SWIG versions 4.3 and 4.4. Closes: numpy#30122
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
3 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
The
import_arraymacro, which is defined in the filenumpy/core/code_generators/generate_numpy_api.py, is intended for use inside an internal SWIG function that is called in the generated C wrapper file. This macro contains a return statement whose argument must match the function definition.Until version 4.3 of SWIG, the aforementioned function returned a
void*value. However, in version 4.4, the return value was changed toint. This causes compilation of code using import_array() to fail with the following error message:returning 'void *' from a function with return type 'int' makes integer from pointer without a cast [-Wint-conversion].This commit resolves the issue by returning either
NULLor0, depending on the SWIG version being used (< 4.4 or >= 4.4, respectively). This change has been successfully tested against SWIG versions 4.3 and 4.4.Closes: #30122