Install requirements from pyproject

news/11440.feature.rst

@@ -0,0 +1 @@
+Handle pyproject.toml in "install -r".

src/pip/_internal/cli/req_command.py

@@ -31,8 +31,8 @@
     install_req_from_parsed_requirement,
     install_req_from_req_string,
 )
+from pip._internal.req.dependencies_file import parse_dependencies, parse_requirements
 from pip._internal.req.req_dependency_group import parse_dependency_groups
-from pip._internal.req.req_file import parse_requirements
 from pip._internal.req.req_install import InstallRequirement
 from pip._internal.resolution.base import BaseResolver
 from pip._internal.utils.temp_dir import (
@@ -269,7 +269,7 @@ def get_requirements(
 
         # NOTE: options.require_hashes may be set if --require-hashes is True
         for filename in options.requirements:
-            for parsed_req in parse_requirements(
+            for parsed_req in parse_dependencies(
                 filename, finder=finder, options=options, session=session
             ):
                 req_to_add = install_req_from_parsed_requirement(

src/pip/_internal/req/dependencies_file.py

@@ -0,0 +1,31 @@
+"""
+Common actions for dealing with dependencies file,
+either requirements.txt or pyproject.toml
+"""
+
+from __future__ import annotations
+
+import optparse
+import pathlib
+from collections.abc import Generator
+
+from pip._internal.index.package_finder import PackageFinder
+from pip._internal.network.session import PipSession
+from pip._internal.req.pyproject_file import parse_pyproject_requirements
+from pip._internal.req.req_file import ParsedRequirement, parse_requirements
+
+
+def parse_dependencies(
+    filename: str,
+    session: PipSession,
+    finder: PackageFinder | None = None,
+    options: optparse.Values | None = None,
+) -> Generator[ParsedRequirement, None, None]:
+    if pathlib.PurePath(filename).name == "pyproject.toml":
+        return parse_pyproject_requirements(
+            filename, finder=finder, options=options, session=session
+        )
+    else:
+        return parse_requirements(
+            filename, finder=finder, options=options, session=session
+        )

src/pip/_internal/req/pyproject_file.py

@@ -0,0 +1,42 @@
+from __future__ import annotations
+
+import optparse
+from collections.abc import Generator
+
+from pip._internal.exceptions import InstallationError
+from pip._internal.index.package_finder import PackageFinder
+from pip._internal.network.session import PipSession
+from pip._internal.req.req_file import ParsedRequirement
+from pip._internal.utils.compat import tomllib
+
+
+def parse_pyproject_requirements(
+    filename: str,
+    session: PipSession,
+    finder: PackageFinder | None = None,
+    options: optparse.Values | None = None,
+) -> Generator[ParsedRequirement, None, None]:
+    try:
+        with open(filename, "rb") as f:
+            pyproject = tomllib.load(f)
+    except OSError as exc:
+        raise InstallationError(f"Could not open requirements file: {exc}")
+
+    project = pyproject.get("project", {})
+    dynamic = project.get("dynamic", [])
+
+    if "dependencies" in dynamic:
+        raise InstallationError(
+            "Installing dynamic dependencies is not supported "
+            "(dynamic dependencies in {filename})"
+        )
+
+    for dependency_line in project.get("dependencies", []):
+        yield ParsedRequirement(
+            requirement=dependency_line,
+            is_editable=False,
+            comes_from=f"-r {filename}",
+            constraint=False,
+            options={},  # TODO
+            line_source=filename,
+        )