144 something to opt into requirements.txt

src/usethis/_core/tool.py

@@ -1,11 +1,13 @@
+from pathlib import Path
+
 from usethis._ci import (
     add_bitbucket_pre_commit_step,
     is_bitbucket_used,
     remove_bitbucket_pre_commit_step,
     remove_bitbucket_pytest_steps,
     update_bitbucket_pytest_steps,
 )
-from usethis._console import box_print
+from usethis._console import box_print, info_print, tick_print
 from usethis._integrations.pre_commit.core import (
     install_pre_commit_hooks,
     remove_pre_commit_config,
@@ -18,6 +20,7 @@
     ignore_ruff_rules,
     select_ruff_rules,
 )
+from usethis._integrations.uv.call import call_uv_subprocess
 from usethis._integrations.uv.deps import add_deps_to_group, remove_deps_from_group
 from usethis._integrations.uv.init import ensure_pyproject_toml
 from usethis._tool import (
@@ -26,6 +29,7 @@
     PreCommitTool,
     PyprojectFmtTool,
     PytestTool,
+    RequirementsTxtTool,
     RuffTool,
 )
 
@@ -57,6 +61,15 @@ def use_pre_commit(*, remove: bool = False) -> None:
         for _tool in ALL_TOOLS:
             if _tool.is_used():
                 _tool.add_pre_commit_repo_configs()
+
+        if PyprojectFmtTool().is_used():
+            # We will use pre-commit instead of the dev-dep.
+            remove_deps_from_group(PyprojectFmtTool().get_unique_dev_deps(), "dev")
+            use_pyproject_fmt()
+
+        if RequirementsTxtTool().is_used():
+            use_requirements_txt()
+
         if not get_hook_names():
             add_placeholder_hook()
 
@@ -84,6 +97,9 @@ def use_pre_commit(*, remove: bool = False) -> None:
         if PyprojectFmtTool().is_used():
             use_pyproject_fmt()
 
+        if RequirementsTxtTool().is_used():
+            use_requirements_txt()
+
 
 def use_pyproject_fmt(*, remove: bool = False) -> None:
     tool = PyprojectFmtTool()
@@ -148,6 +164,50 @@ def use_pytest(*, remove: bool = False) -> None:
         remove_pytest_dir()  # Last, since this is a manual step
 
 
+def use_requirements_txt(*, remove: bool = False) -> None:
+    tool = RequirementsTxtTool()
+
+    path = Path.cwd() / "requirements.txt"
+
+    if not remove:
+        is_pre_commit = PreCommitTool().is_used()
+
+        if is_pre_commit:
+            tool.add_pre_commit_repo_configs()
+
+        if not path.exists():
+            # N.B. this is where a task runner would come in handy, to reduce duplication.
+            tick_print("Writing 'requirements.txt'.")
+            call_uv_subprocess(
+                [
+                    "export",
+                    "--frozen",
+                    "--no-dev",
+                    "--output-file=requirements.txt",
+                    "--quiet",
+                ]
+            )
+
+        if not is_pre_commit:
+            box_print(
+                "Call the 'uv export --frozen --no-dev --output-file=requirements.txt --quiet' command to manually export to 'requirements.txt'."
+            )
+            info_print(
+                "You can automate the export of requirements.txt with pre-commit. Try `usethis tool pre-commit`."
+            )
+        else:
+            box_print(
+                "Call the 'pre-commit run uv-export' command to manually export to 'requirements.txt'."
+            )
+    else:
+        if PreCommitTool().is_used():
+            tool.remove_pre_commit_repo_configs()
+
+        if path.exists() and path.is_file():
+            tick_print("Removing 'requirements.txt'.")
+            path.unlink()
+
+
 def use_ruff(*, remove: bool = False) -> None:
     tool = RuffTool()
 

src/usethis/_integrations/pre_commit/hooks.py

@@ -16,6 +16,7 @@
 
 _HOOK_ORDER = [
     "validate-pyproject",
+    "uv-export",
     "pyproject-fmt",
     "ruff",  # ruff followed by ruff-format seems to be the recommended way by Astral
     "ruff-format",

src/usethis/_interface/tool.py

@@ -10,6 +10,7 @@
     use_pre_commit,
     use_pyproject_fmt,
     use_pytest,
+    use_requirements_txt,
     use_ruff,
 )
 from usethis.errors import UsethisError
@@ -59,6 +60,17 @@ def pytest(
         _run_tool(use_pytest, remove=remove)
 
 
+@app.command(
+    name="requirements.txt",
+    help="Use a requirements.txt file exported from the uv lockfile.",
+)
+def requirements_txt(
+    remove: bool = remove_opt, offline: bool = offline_opt, quiet: bool = quiet_opt
+) -> None:
+    with usethis_config.set(offline=offline, quiet=quiet):
+        _run_tool(use_requirements_txt, remove=remove)
+
+
 @app.command(help="Use Ruff: an extremely fast Python linter and code formatter.")
 def ruff(
     remove: bool = remove_opt, offline: bool = offline_opt, quiet: bool = quiet_opt

src/usethis/_tool.py

@@ -288,6 +288,37 @@ def get_managed_files(self):
         return [Path("tests/conftest.py")]
 
 
+class RequirementsTxtTool(Tool):
+    @property
+    def name(self) -> str:
+        return "requirements.txt"
+
+    @property
+    def dev_deps(self) -> list[str]:
+        return []
+
+    def get_pre_commit_repos(self) -> list[LocalRepo | UriRepo]:
+        return [
+            LocalRepo(
+                repo="local",
+                hooks=[
+                    HookDefinition(
+                        id="uv-export",
+                        name="uv-export",
+                        files="^uv\\.lock$",
+                        pass_filenames=False,
+                        entry="uv export --frozen --no-dev --output-file=requirements.txt --quiet",
+                        language=Language("system"),
+                        require_serial=True,
+                    )
+                ],
+            )
+        ]
+
+    def get_managed_files(self) -> list[Path]:
+        return [Path("requirements.txt")]
+
+
 class RuffTool(Tool):
     @property
     def name(self) -> str:
@@ -359,5 +390,6 @@ def get_managed_files(self):
     PreCommitTool(),
     PyprojectFmtTool(),
     PytestTool(),
+    RequirementsTxtTool(),
     RuffTool(),
 ]

tests/usethis/_core/test_tool.py

@@ -572,7 +572,7 @@ def test_use_after(self, uv_init_repo_dir: Path):
             assert "pyproject-fmt" in hook_names
 
         @pytest.mark.usefixtures("_vary_network_conn")
-        def test_remove(
+        def test_remove_with_precommit(
             self, uv_init_repo_dir: Path, capfd: pytest.CaptureFixture[str]
         ):
             with change_cwd(uv_init_repo_dir):
@@ -592,6 +592,27 @@ def test_remove(
             assert out == (
                 "✔ Removing pyproject-fmt config from 'pyproject.toml'.\n"
                 "✔ Removing hook 'pyproject-fmt' from '.pre-commit-config.yaml'.\n"
+            )
+            # N.B. we don't remove it as a dependency because it's not a dep when
+            # pre-commit is used.
+
+        @pytest.mark.usefixtures("_vary_network_conn")
+        def test_remove_without_precommit(
+            self, uv_init_repo_dir: Path, capfd: pytest.CaptureFixture[str]
+        ):
+            with change_cwd(uv_init_repo_dir):
+                # Arrange
+                with usethis_config.set(quiet=True):
+                    use_pyproject_fmt()
+
+                # Act
+                use_pyproject_fmt(remove=True)
+
+            # Assert
+            out, err = capfd.readouterr()
+            assert not err
+            assert out == (
+                "✔ Removing pyproject-fmt config from 'pyproject.toml'.\n"
                 "✔ Removing dependency 'pyproject-fmt' from the 'dev' group in 'pyproject.toml'.\n"
             )