Build fails with precision=double

[van800]

Godot version

4.5

godot-cpp version

4.5

System information

all OS

Issue description

in the godot-cpp branch 4.5
gdextension/extension_api.json
contains
"precision": "single"
which prevents compiling gdextension with precision=double

I am getting:
Cannot do a precision=double build using 'godot-cpp/gdextension/extension_api.json' which was generated by Godot built with precision=single
in https://github.com/JetBrains/godot-support/actions/runs/23481943723/job/68327711213

Full error message

Run scons target=editor platform=macos arch=universal precision=double
scons: Reading SConscript files ...
Auto-detected 3 CPU cores available for build parallelism. Using 3 cores by default. You can override it with the -j argument.
Building for architecture universal on platform macos
scons: done reading SConscript files.
scons: Building targets ...
Generating godot-cpp/gen/include/godot_cpp/core/ext_wrappers.gen.inc ...
Compiling godot-cpp/src/core/memory.cpp ...
scons: *** [godot-cpp/gen/include/godot_cpp/core/ext_wrappers.gen.inc] Exception : Cannot do a precision=double build using 'godot-cpp/gdextension/extension_api.json' which was generated by Godot built with precision=single
Compiling shared src/rider_path_locator_common.cpp ...
Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/3.14/lib/python3.14/site-packages/SCons/Action.py", line 1318, in execute
    result = self.execfunction(target=target, source=rsources, env=env)
  File "/Users/runner/work/godot-support/godot-support/godot-editor-plugin/addons/rider-plugin/cpp/godot-cpp/tools/godotcpp.py", line 162, in scons_generate_bindings
    _generate_bindings(
    ~~~~~~~~~~~~~~~~~~^
        api,
        ^^^^
    ...<4 lines>...
        env["godot_cpp_gen_dir"],
        ^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/Users/runner/work/godot-support/godot-support/godot-editor-plugin/addons/rider-plugin/cpp/godot-cpp/binding_generator.py", line 289, in _generate_bindings
    raise Exception(
        f"Cannot do a precision={precision} build using '{api_filepath}' which was generated by Godot built with precision={api['header']['precision']}"
    )
Exception: Cannot do a precision=double build using 'godot-cpp/gdextension/extension_api.json' which was generated by Godot built with precision=single
scons: building terminated because of errors.

[dsnopek]

To build with double precision you need to provide your own extension_api.json dumped from a Godot that was built with double precision. I presume you already have one, so this is just a matter of running godot --dump-extension-api and then pointing SCons at it via scons custom_api_file=path/to/extension_api.json

[Ivorforce]

I think the error message is already pretty decent, but maybe we should add an "action item" to it? Like refer to the docs or something

[van800]

I just want the gdextension to be compiled on CI with both single and double precision.
It worked with godot-cpp 4.4 and stopped working with godot-cpp 4.5.
I have never tried myself Godot with double precision.

[Ivorforce]

Just to be clear: Your workflow was also broken before. What happened before godot-cpp 4.5 was that it didn't recognize you were using the wrong extension_api.json file, and it was using the single-precision file instead. This might have worked in some situations, but would eventually crash in others.
The only thing that changed in godot-cpp 4.5 is that the system now realizes this improper usage is happening and prevents you from doing it.

[van800]

Thank you for explaining!
I think I will drop the double precision builds for now and think of it again, if there would be requests for it.
Please feel free to close the ticket, if there is nothing you want to improve regarding the message clarity of supplying both signle and double extension_api.json in advance.