What is variable 'MESON_CMAKE_ROOT'?

[sinkinben]

When I build some projects (scripts are provided by others), some errors are thrown by meson.

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/mesonbuild/mesonmain.py", line 129, in run
    return options.run_func(options)
  File "/usr/lib/python3/dist-packages/mesonbuild/msetup.py", line 245, in run
    app.generate()
  File "/usr/lib/python3/dist-packages/mesonbuild/msetup.py", line 159, in generate
    self._generate(env)
  File "/usr/lib/python3/dist-packages/mesonbuild/msetup.py", line 192, in _generate
    intr.run()
  File "/usr/lib/python3/dist-packages/mesonbuild/interpreter.py", line 4167, in run
    super().run()
  File "/usr/lib/python3/dist-packages/mesonbuild/interpreterbase.py", line 412, in run
    self.evaluate_codeblock(self.ast, start=1)
  File "/usr/lib/python3/dist-packages/mesonbuild/interpreterbase.py", line 436, in evaluate_codeblock
    raise e
  File "/usr/lib/python3/dist-packages/mesonbuild/interpreterbase.py", line 430, in evaluate_codeblock
    self.evaluate_statement(cur)
  File "/usr/lib/python3/dist-packages/mesonbuild/interpreterbase.py", line 473, in evaluate_statement
    return self.evaluate_foreach(cur)
  File "/usr/lib/python3/dist-packages/mesonbuild/interpreterbase.py", line 700, in evaluate_foreach
    self.evaluate_codeblock(node.block)
  File "/usr/lib/python3/dist-packages/mesonbuild/interpreterbase.py", line 436, in evaluate_codeblock
    raise e
  File "/usr/lib/python3/dist-packages/mesonbuild/interpreterbase.py", line 430, in evaluate_codeblock
    self.evaluate_statement(cur)
  File "/usr/lib/python3/dist-packages/mesonbuild/interpreterbase.py", line 441, in evaluate_statement
    return self.function_call(cur)
  File "/usr/lib/python3/dist-packages/mesonbuild/interpreterbase.py", line 788, in function_call
    return func(node, posargs, kwargs)
  File "/usr/lib/python3/dist-packages/mesonbuild/interpreterbase.py", line 285, in wrapped
    return f(*wrapped_args, **wrapped_kwargs)
  File "/usr/lib/python3/dist-packages/mesonbuild/interpreterbase.py", line 174, in wrapped
    return f(*wrapped_args, **wrapped_kwargs)
  File "/usr/lib/python3/dist-packages/mesonbuild/interpreter.py", line 3689, in func_subdir
    self.evaluate_codeblock(codeblock)
  File "/usr/lib/python3/dist-packages/mesonbuild/interpreterbase.py", line 436, in evaluate_codeblock
    raise e
  File "/usr/lib/python3/dist-packages/mesonbuild/interpreterbase.py", line 430, in evaluate_codeblock
    self.evaluate_statement(cur)
  File "/usr/lib/python3/dist-packages/mesonbuild/interpreterbase.py", line 451, in evaluate_statement
    return self.evaluate_if(cur)
  File "/usr/lib/python3/dist-packages/mesonbuild/interpreterbase.py", line 530, in evaluate_if
    self.evaluate_codeblock(i.block)
  File "/usr/lib/python3/dist-packages/mesonbuild/interpreterbase.py", line 436, in evaluate_codeblock
    raise e
  File "/usr/lib/python3/dist-packages/mesonbuild/interpreterbase.py", line 430, in evaluate_codeblock
    self.evaluate_statement(cur)
  File "/usr/lib/python3/dist-packages/mesonbuild/interpreterbase.py", line 443, in evaluate_statement
    return self.assignment(cur)
  File "/usr/lib/python3/dist-packages/mesonbuild/interpreterbase.py", line 1064, in assignment
    value = self.evaluate_statement(node.value)
  File "/usr/lib/python3/dist-packages/mesonbuild/interpreterbase.py", line 441, in evaluate_statement
    return self.function_call(cur)
  File "/usr/lib/python3/dist-packages/mesonbuild/interpreterbase.py", line 788, in function_call
    return func(node, posargs, kwargs)
  File "/usr/lib/python3/dist-packages/mesonbuild/interpreterbase.py", line 285, in wrapped
    return f(*wrapped_args, **wrapped_kwargs)
  File "/usr/lib/python3/dist-packages/mesonbuild/interpreterbase.py", line 285, in wrapped
    return f(*wrapped_args, **wrapped_kwargs)
  File "/usr/lib/python3/dist-packages/mesonbuild/interpreterbase.py", line 285, in wrapped
    return f(*wrapped_args, **wrapped_kwargs)
  [Previous line repeated 2 more times]
  File "/usr/lib/python3/dist-packages/mesonbuild/interpreterbase.py", line 155, in wrapped
    ret = f(*wrapped_args, **wrapped_kwargs)
  File "/usr/lib/python3/dist-packages/mesonbuild/interpreterbase.py", line 174, in wrapped
    return f(*wrapped_args, **wrapped_kwargs)
  File "/usr/lib/python3/dist-packages/mesonbuild/interpreter.py", line 3236, in func_dependency
    d = self.dependency_impl(name, display_name, kwargs)
  File "/usr/lib/python3/dist-packages/mesonbuild/interpreter.py", line 3283, in dependency_impl
    dep = dependencies.find_external_dependency(name, self.environment, kwargs)
  File "/usr/lib/python3/dist-packages/mesonbuild/dependencies/base.py", line 2234, in find_external_dependency
    d = c()
  File "/usr/lib/python3/dist-packages/mesonbuild/dependencies/base.py", line 1104, in __init__
    CMakeDependency.class_cmakeinfo[self.for_machine] = self._get_cmake_info()
  File "/usr/lib/python3/dist-packages/mesonbuild/dependencies/base.py", line 1198, in _get_cmake_info
    'cmake_root': temp_parser.get_cmake_var('MESON_CMAKE_ROOT')[0],
IndexError: list index out of range

What is MESON_CMAKE_ROOT ? How can I fix this?

• I search such log on google/stackoverflow, but got little information.
• export MESON_CMAKE_ROOT=/usr/bin/cmake does not work.

Shall I need to define MESON_CMAKE_ROOT in cmake files?

[eli-schwartz]

It's an internal implementation detail of meson that is used when meson generates a dummy cmake project to see if a dependency can be found using find_package(). It should never show up exposed to users and the fact that it produces an IndexError indicates a meson bug.

What version of meson did you use?

[sinkinben]

This problem can be solved by installing meson (pip install meson).