[bug] missing CMakeUserPresets.json

Conan 1.48.0 does not generate CMakeUserPresets.json if conanfile.txt used instead of .py.

Probably this is duplicate of #11172.

Environment Details

• Operating System: linux
• Conan version: 1.48.0

Steps to reproduce

cd "$(mktemp -d)"
conan new hello/0.1 -m=cmake_exe
rm conanfile.py
echo -e "[generators]\nCMakeToolchain" > conanfile.txt
mkdir build
(cd build && conan install ..)
tree "$(pwd)"

Output

/tmp/tmp.6FdEpSMGTR
├── CMakeLists.txt
├── build
│   ├── CMakePresets.json
│   ├── conan.lock
│   ├── conan_toolchain.cmake
│   ├── conanbuildinfo.txt
│   ├── conaninfo.txt
│   └── graph_info.json
├── conanfile.txt
├── include
│   └── hello.h
├── src
│   ├── hello.cpp
│   └── main.cpp
└── test_package
    └── conanfile.py

[lasote]

We have finally implemented https://github.com/conan-io/conan/pull/11348 to be released in Conan 1.49. So you can declare:

[layout]
cmake_layout

in the conanfile.txt to get the CMakeUserPresets.json generated correctly

[memsharded]

Does it mean that usage of .txt is discouraged and will be deprecated in 2.0?

No, the .txt will still be there. And the new CMake integration will still generate a CMakePresets.json file, it is only the CMakeUserPresets.json that might be generated under certain conditions (it is not already existing), and that might be used to aggregate multiple different configurations (each one might have a different CMakePresets.json in a different folder), but for this functionality to be manageable, a layout is necessary, otherwise it becomes too messy. So it is the CMakeUserPresets.json that only will be generated for more advanced cases that will require a conanfile.py, while for simple usage a conanfile.txt with the CMakePresets.json would be the solution.