`Failed to build atheris==3.0.0`

[khteh]

Ubuntu 26.04, Python 3.14.4

 x Failed to build `atheris==3.0.0`
  |-> The build backend returned an error
  `-> Call to `setuptools.build_meta:__legacy__.build_wheel` failed (exit
      status: 1)

      [stdout]
      running bdist_wheel
      running build
      running build_py
      creating build/lib.linux-x86_64-cpython-314
      copying atheris_no_libfuzzer.py -> build/lib.linux-x86_64-cpython-314
      creating build/lib.linux-x86_64-cpython-314/atheris
      copying src/custom_mutator_fuzz_test.py ->
      build/lib.linux-x86_64-cpython-314/atheris
      copying src/__init__.py -> build/lib.linux-x86_64-cpython-314/atheris
      copying src/pyinstaller_coverage_test.py ->
      build/lib.linux-x86_64-cpython-314/atheris
      copying src/version_dependent.py ->
      build/lib.linux-x86_64-cpython-314/atheris
      copying src/str_hook_test.py ->
      build/lib.linux-x86_64-cpython-314/atheris
      copying src/fuzz_test.py -> build/lib.linux-x86_64-cpython-314/atheris
      copying src/import_hook.py -> build/lib.linux-x86_64-cpython-314/atheris
      copying src/regex_coverage_test.py ->
      build/lib.linux-x86_64-cpython-314/atheris
      copying src/fuzzed_data_provider_test.py ->
      build/lib.linux-x86_64-cpython-314/atheris
      copying src/instrument_bytecode_test.py ->
      build/lib.linux-x86_64-cpython-314/atheris
      copying src/fuzz_test_lib.py ->
      build/lib.linux-x86_64-cpython-314/atheris
      copying src/instrument_all_test.py ->
      build/lib.linux-x86_64-cpython-314/atheris
      copying src/function_hooks.py ->
      build/lib.linux-x86_64-cpython-314/atheris
      copying src/custom_crossover_fuzz_test.py ->
      build/lib.linux-x86_64-cpython-314/atheris
      copying src/instrument_bytecode.py ->
      build/lib.linux-x86_64-cpython-314/atheris
      copying src/custom_mutator_and_crossover_fuzz_test.py ->
      build/lib.linux-x86_64-cpython-314/atheris
      copying src/regex_match_generation_test.py ->
      build/lib.linux-x86_64-cpython-314/atheris
      copying src/hook-atheris.py -> build/lib.linux-x86_64-cpython-314/atheris
      copying src/utils.py -> build/lib.linux-x86_64-cpython-314/atheris
      creating build/lib.linux-x86_64-cpython-314/atheris/mock_libfuzzer
      copying src/mock_libfuzzer/mockutils.py ->
      build/lib.linux-x86_64-cpython-314/atheris/mock_libfuzzer
      running build_ext

      [stderr]
      /root/.cache/uv/sdists-v9/pypi/atheris/3.0.0/cZCeBGz_zTp1qpXplA9QB/src/setup_utils/find_libfuzzer.sh:
      line 44: clang: command not found
      Failed to find libFuzzer; set either $CLANG_BIN to point to your Clang
      binary, or $LIBFUZZER_LIB to point directly to your libFuzzer .a file.
      If needed, download and build the latest version of Clang:
          git clone --depth=1 https://github.com/llvm/llvm-project.git
          cd llvm-project
          cmake -DLLVM_ENABLE_PROJECTS='clang;compiler-rt' -G "Unix Makefiles"
      -S llvm -B build
          NPROC=$(sysctl -n hw.logicalcpu 2>/dev/null || nproc)
          cmake --build build --parallel $NPROC # This step is very slow.
      Then, set $CLANG_BIN="$(pwd)/bin/clang" and run pip again.
      You should use this same Clang for building any Python extensions you
      plan to fuzz.

      Traceback (most recent call last):
        File "<string>", line 107, in get_libfuzzer_lib
        File "/usr/lib/python3.14/subprocess.py", line 473, in check_output
          return run(*popenargs, stdout=PIPE, timeout=timeout, check=True,
                 ~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
                     **kwargs).stdout
                     ^^^^^^^^^
        File "/usr/lib/python3.14/subprocess.py", line 578, in run
          raise CalledProcessError(retcode, process.args,
                                   output=stdout, stderr=stderr)
      subprocess.CalledProcessError: Command
      '['/root/.cache/uv/sdists-v9/pypi/atheris/3.0.0/cZCeBGz_zTp1qpXplA9QB/src/setup_utils/find_libfuzzer.sh']'
      returned non-zero exit status 1.

      During handling of the above exception, another exception occurred:

      Traceback (most recent call last):
        File "<string>", line 11, in <module>
          wheel_filename =
      backend.build_wheel("/root/.cache/uv/builds-v0/.tmp2CAp1Q", {}, None)
        File
      "/root/.cache/uv/builds-v0/.tmpe7oLrG/lib/python3.14/site-packages/setuptools/build_meta.py",
      line 438, in build_wheel
          return _build(['bdist_wheel'])
        File
      "/root/.cache/uv/builds-v0/.tmpe7oLrG/lib/python3.14/site-packages/setuptools/build_meta.py",
      line 429, in _build
          return self._build_with_temp_dir(
                 ~~~~~~~~~~~~~~~~~~~~~~~~~^
              cmd,
              ^^^^
          ...<3 lines>...
              self._arbitrary_args(config_settings),
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
          )
          ^
        File
      "/root/.cache/uv/builds-v0/.tmpe7oLrG/lib/python3.14/site-packages/setuptools/build_meta.py",
      line 410, in _build_with_temp_dir
          self.run_setup()
          ~~~~~~~~~~~~~~^^
        File
      "/root/.cache/uv/builds-v0/.tmpe7oLrG/lib/python3.14/site-packages/setuptools/build_meta.py",
      line 520, in run_setup
          super().run_setup(setup_script=setup_script)
          ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^
        File
      "/root/.cache/uv/builds-v0/.tmpe7oLrG/lib/python3.14/site-packages/setuptools/build_meta.py",
      line 317, in run_setup
          exec(code, locals())
          ~~~~^^^^^^^^^^^^^^^^
        File "<string>", line 460, in <module>
        File
      "/root/.cache/uv/builds-v0/.tmpe7oLrG/lib/python3.14/site-packages/setuptools/__init__.py",
      line 117, in setup
          return distutils.core.setup(**attrs)  # type: ignore[return-value]
                 ~~~~~~~~~~~~~~~~~~~~^^^^^^^^^
        File
      "/root/.cache/uv/builds-v0/.tmpe7oLrG/lib/python3.14/site-packages/setuptools/_distutils/core.py",
      line 186, in setup
          return run_commands(dist)
        File
      "/root/.cache/uv/builds-v0/.tmpe7oLrG/lib/python3.14/site-packages/setuptools/_distutils/core.py",
      line 202, in run_commands
          dist.run_commands()
          ~~~~~~~~~~~~~~~~~^^
        File
      "/root/.cache/uv/builds-v0/.tmpe7oLrG/lib/python3.14/site-packages/setuptools/_distutils/dist.py",
      line 1000, in run_commands
          self.run_command(cmd)
          ~~~~~~~~~~~~~~~~^^^^^
        File
      "/root/.cache/uv/builds-v0/.tmpe7oLrG/lib/python3.14/site-packages/setuptools/dist.py",
      line 1107, in run_command
          super().run_command(command)
          ~~~~~~~~~~~~~~~~~~~^^^^^^^^^
        File
      "/root/.cache/uv/builds-v0/.tmpe7oLrG/lib/python3.14/site-packages/setuptools/_distutils/dist.py",
      line 1019, in run_command
          cmd_obj.run()
          ~~~~~~~~~~~^^
        File
      "/root/.cache/uv/builds-v0/.tmpe7oLrG/lib/python3.14/site-packages/setuptools/command/bdist_wheel.py",
      line 370, in run
          self.run_command("build")
          ~~~~~~~~~~~~~~~~^^^^^^^^^
        File
      "/root/.cache/uv/builds-v0/.tmpe7oLrG/lib/python3.14/site-packages/setuptools/_distutils/cmd.py",
      line 341, in run_command
          self.distribution.run_command(command)
          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^
        File
      "/root/.cache/uv/builds-v0/.tmpe7oLrG/lib/python3.14/site-packages/setuptools/dist.py",
      line 1107, in run_command
          super().run_command(command)
          ~~~~~~~~~~~~~~~~~~~^^^^^^^^^
        File
      "/root/.cache/uv/builds-v0/.tmpe7oLrG/lib/python3.14/site-packages/setuptools/_distutils/dist.py",
      line 1019, in run_command
          cmd_obj.run()
          ~~~~~~~~~~~^^
        File
      "/root/.cache/uv/builds-v0/.tmpe7oLrG/lib/python3.14/site-packages/setuptools/_distutils/command/build.py",
      line 135, in run
          self.run_command(cmd_name)
          ~~~~~~~~~~~~~~~~^^^^^^^^^^
        File
      "/root/.cache/uv/builds-v0/.tmpe7oLrG/lib/python3.14/site-packages/setuptools/_distutils/cmd.py",
      line 341, in run_command
          self.distribution.run_command(command)
          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^
        File
      "/root/.cache/uv/builds-v0/.tmpe7oLrG/lib/python3.14/site-packages/setuptools/dist.py",
      line 1107, in run_command
          super().run_command(command)
          ~~~~~~~~~~~~~~~~~~~^^^^^^^^^
        File
      "/root/.cache/uv/builds-v0/.tmpe7oLrG/lib/python3.14/site-packages/setuptools/_distutils/dist.py",
      line 1019, in run_command
          cmd_obj.run()
          ~~~~~~~~~~~^^
        File
      "/root/.cache/uv/builds-v0/.tmpe7oLrG/lib/python3.14/site-packages/setuptools/command/build_ext.py",
      line 97, in run
          _build_ext.run(self)
          ~~~~~~~~~~~~~~^^^^^^
        File
      "/root/.cache/uv/builds-v0/.tmpe7oLrG/lib/python3.14/site-packages/setuptools/_distutils/command/build_ext.py",
      line 367, in run
          self.build_extensions()
          ~~~~~~~~~~~~~~~~~~~~~^^
        File "<string>", line 347, in build_extensions
        File "<string>", line 111, in get_libfuzzer_lib
      RuntimeError: Failed to find libFuzzer; set either $CLANG_BIN to point
      to your Clang binary, or $LIBFUZZER_LIB to point directly to your
      libFuzzer .a file. If needed, download and build the latest version
      of Clang:
          git clone --depth=1 https://github.com/llvm/llvm-project.git
          cd llvm-project
          cmake -DLLVM_ENABLE_PROJECTS='clang;compiler-rt' -G "Unix Makefiles"
      -S llvm -B build
          NPROC=$(sysctl -n hw.logicalcpu 2>/dev/null || nproc)
          cmake --build build --parallel $NPROC # This step is very slow.
      Then, set $CLANG_BIN="$(pwd)/bin/clang" and run pip again.
      You should use this same Clang for building any Python extensions you
      plan to fuzz.


      hint: This usually indicates a problem with the package or the build
      environment.
  help: `atheris` (v3.0.0) was included because `rag-agent:dev` (v1.0.0)
        depends on `atheris`

Exited with code exit status 1

[MaGaroo]

Do you have clang on your system?

      line 44: clang: command not found
      Failed to find libFuzzer; set either $CLANG_BIN to point to your Clang
      binary, or $LIBFUZZER_LIB to point directly to your libFuzzer .a file.
      If needed, download and build the latest version of Clang:
          git clone --depth=1 https://github.com/llvm/llvm-project.git
          cd llvm-project
          cmake -DLLVM_ENABLE_PROJECTS='clang;compiler-rt' -G "Unix Makefiles"
      -S llvm -B build
          NPROC=$(sysctl -n hw.logicalcpu 2>/dev/null || nproc)
          cmake --build build --parallel $NPROC # This step is very slow.
      Then, set $CLANG_BIN="$(pwd)/bin/clang" and run pip again.
      You should use this same Clang for building any Python extensions you
      plan to fuzz.

[khteh]

Does this make sense for container app used in CI/CD to run the fuzz testing?

[khteh]

Yes, clang is preinstalled with the Ubuntu distribution:

$ which clang
/usr/bin/clang
$ clang --version
Ubuntu clang version 21.1.8 (6ubuntu1)
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/lib/llvm-21/bin