Add extra-arguments for Conan CLI overrides in pyproject.toml (#47)

* add extra-arguments

* wip

* bump version

Author: czoido

docs/configuration.md

@@ -20,6 +20,7 @@ All project-level options live under
 |--------|--------------|-------------|---------|
 | `conanfile-path` | `[tool.conan-py-build]` | Path to the Conan recipe, relative to project root | `"."` |
 | `extra-profile` | `[tool.conan-py-build]` | Extra Conan profile composed on top of the active one | (none) |
+| `extra-arguments` | `[tool.conan-py-build]` | Extra Conan CLI flags appended to `conan build` and `conan export-pkg` | `[]` |
 | `version.file` | `[tool.conan-py-build.version]` | Python file with `__version__` | (none) |
 | `version.provider` | `[tool.conan-py-build.version]` | `"setuptools_scm"` for version from git tags | (none) |
 | `packages` | `[tool.conan-py-build.wheel]` | Paths to Python packages in the wheel | `["src/<name>"]` |
@@ -29,6 +30,10 @@ Variants for extra profiles: `extra-profile-host`,
 `extra-profile-build`, `extra-profile-all`.
 Paths relative to project root.
 
+For one-off Conan overrides without shipping a separate
+profile file, use `extra-arguments` (see *Extra Conan
+arguments* below).
+
 Default `packages` is `src/<normalized_project_name>`
 (hyphens → underscores).
 
@@ -119,6 +124,47 @@ or `CONAN_HOME` / `.conanrc`). Set
 `CONAN_PY_BUILD_PROFILE_AUTODETECT=1` to autodetect
 the profile instead of requiring `default`.
 
+## Extra Conan arguments
+
+CLI flags appended to `conan build` and
+`conan export-pkg`. Symmetric with `extra-profile`,
+with higher precedence — CLI flags win against any
+profile entry.
+
+Bump `compiler.cppstd` to match a transitive dep
+(e.g. `gdal/3.12.1` requires C++17, MSVC defaults
+to 14):
+
+```toml
+[tool.conan-py-build]
+extra-arguments = ["-s=compiler.cppstd=17"]
+```
+
+Disable an optional dep feature and pin parallelism:
+
+```toml
+[tool.conan-py-build]
+extra-arguments = [
+    "-o=gdal/*:with_arrow=False",
+    "-c=tools.build:jobs=4",
+]
+```
+
+For values with embedded double quotes (dict / list
+`[conf]` literals), use TOML literal strings (`'...'`):
+
+```toml
+extra-arguments = [
+    '-c=tools.build:cflags+=["-O2", "-fPIC"]',
+    '-c=tools.cmake.cmaketoolchain:extra_variables={"FOO": "bar"}',
+]
+```
+
+Any Conan CLI flag works: `-s` / `-o` / `-c` (host),
+`-s:b` / `-o:b` / `-c:b` (build context),
+`--build=...`, `--lockfile=...`. Pair-form
+(`["-s", "compiler.cppstd=17"]`) is also accepted.
+
 ## Entry points (PEP 621)
 
 `[project.scripts]`, `[project.gui-scripts]` and

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "conan-py-build"
-version = "0.4.2"
+version = "0.4.3"
 description = "A minimal PEP 517 compliant build backend that uses Conan to build Python C/C++ extensions"
 readme = "README.md"
 license = {text = "MIT"}

src/conan_py_build/build.py

@@ -225,6 +225,23 @@ def _autodetect_profile() -> bool:
     return env_val in ("1", "true", "yes")
 
 
+def _extra_arguments(tool_cfg: dict) -> List[str]:
+    """Return ``[tool.conan-py-build].extra-arguments`` validated as ``list[str]``.
+
+    Appended verbatim to ``conan build`` and ``conan export-pkg`` invocations,
+    symmetric with ``extra-profile``. Typical uses: ``-s`` / ``-o`` / ``-c``
+    overrides, ``--lockfile``, ``--build=...``, per-context ``-s:b`` flags.
+    """
+    args = tool_cfg.get("extra-arguments")
+    if args is None:
+        return []
+    if not isinstance(args, list) or not all(isinstance(a, str) for a in args):
+        raise RuntimeError(
+            "[tool.conan-py-build].extra-arguments must be a list of strings."
+        )
+    return args
+
+
 def _resolve_default_profiles(conan_api, source_dir: Path, host_profile: str, build_profile: str) -> Tuple[str, str]:
     if host_profile != "default" and build_profile != "default":
         return host_profile, build_profile
@@ -525,6 +542,8 @@ def _do_build_wheel(
         arg = key[len("extra-"):].replace("-", ":", 1)  # profile-host -> profile:host
         profile_args.extend([f"--{arg}", str(p)])
 
+    extra_args = _extra_arguments(tool)
+
     conanfile_path = tool.get("conanfile-path") or "."
     resolved_conanfile = str(_resolve_conanfile_path(conanfile_path, source_dir))
 
@@ -549,6 +568,7 @@ def _do_build_wheel(
         "--build=missing",
     ]
     build_cmd.extend(profile_args)
+    build_cmd.extend(extra_args)
 
     print(
         f"Running conan build (profiles: host={host_profile}, build={build_profile})...",
@@ -580,6 +600,7 @@ def _do_build_wheel(
         user_presets_conf,
     ]
     export_pkg_cmd.extend(profile_args)
+    export_pkg_cmd.extend(extra_args)
     try:
         export_result = conan_api.command.run(export_pkg_cmd)
     except Exception as e:

tests/test_unit.py

@@ -21,6 +21,7 @@
     _get_wheel_packages,
     _create_dist_info,
     _write_entry_points,
+    _extra_arguments,
     _build_wheel_with_tags,
     _copy_license_files_from_paths,
     _validate_version_config,
@@ -157,6 +158,44 @@ def test_move_deploy_to_wheel_copies_shared_libs_next_to_extension(tmp_path):
     assert (pkg / "libdep.so").read_text() == "so"
 
 
+def test_extra_arguments_empty_when_unset():
+    assert _extra_arguments({}) == []
+    assert _extra_arguments({"extra-arguments": []}) == []
+
+
+def test_extra_arguments_returns_list_verbatim():
+    args = ["-s=compiler.cppstd=17", "-o=gdal/*:shared=True", "-c=tools.build:jobs=4"]
+    assert _extra_arguments({"extra-arguments": args}) == args
+
+
+def test_extra_arguments_supports_pair_form():
+    """Pair-form ``["-s", "value"]`` is passed through unchanged — argparse
+    accepts both ``-s value`` and ``-s=value`` on Conan's CLI."""
+    args = ["-s", "compiler.cppstd=17", "-o", "gdal/*:shared=True", "-c", "tools.build:jobs=4"]
+    assert _extra_arguments({"extra-arguments": args}) == args
+
+
+def test_extra_arguments_supports_mixed_pair_and_equals_form():
+    """Mixing equals-form and pair-form in the same list works — argparse
+    processes each token independently."""
+    args = [
+        "-s=compiler.cppstd=17",
+        "-o", "gdal/*:shared=True",
+        "-c=tools.build:jobs=4",
+    ]
+    assert _extra_arguments({"extra-arguments": args}) == args
+
+
+def test_extra_arguments_rejects_non_list():
+    with pytest.raises(RuntimeError, match="must be a list of strings"):
+        _extra_arguments({"extra-arguments": "-s=compiler.cppstd=17"})
+
+
+def test_extra_arguments_rejects_non_string_items():
+    with pytest.raises(RuntimeError, match="must be a list of strings"):
+        _extra_arguments({"extra-arguments": ["-s", {"k": "v"}]})
+
+
 def test_get_sdist_config_minimal_pyproject(tmp_path):
     make_pyproject_minimal(tmp_path)
     assert _get_sdist_config(tmp_path) == {"include": [], "exclude": []}