Add constraints.txt support

README.md

@@ -2,7 +2,7 @@
 
 This package is a plugin that allows the export of locked packages to various formats.
 
-**Note**: For now, only the `requirements.txt` format is available.
+**Note**: For now, only the `constraints.txt` and `requirements.txt` formats are available.
 
 This plugin provides the same features as the existing `export` command of Poetry which it will eventually replace.
 
@@ -36,11 +36,11 @@ The plugin provides an `export` command to export to the desired format.
 poetry export -f requirements.txt --output requirements.txt
 ```
 
-**Note**: Only the `requirements.txt` format is currently supported.
+**Note**: Only the `constraints.txt` and `requirements.txt` formats are currently supported.
 
 ### Available options
 
-* `--format (-f)`: The format to export to (default: `requirements.txt`). Currently, only `requirements.txt` is supported.
+* `--format (-f)`: The format to export to (default: `requirements.txt`). Currently, only `constraints.txt` and `requirements.txt` are supported.
 * `--output (-o)`: The name of the output file.  If omitted, print to standard output.
 * `--without`: The dependency groups to ignore when exporting.
 * `--with`: The optional dependency groups to include when exporting.

docs/_index.md

@@ -14,7 +14,7 @@ menu:
 The export plugin allows the export of locked packages to various formats.
 
 {{% note %}}
-Only the `requirements.txt` format is currently supported.
+Only the `constraints.txt` and `requirements.txt` formats are currently supported.
 {{% /note %}}
 
 ## Exporting packages
@@ -65,7 +65,7 @@ poetry export --only test,docs
 
 ### Available options
 
-* `--format (-f)`: The format to export to (default: `requirements.txt`). Currently, only `requirements.txt` is supported.
+* `--format (-f)`: The format to export to (default: `requirements.txt`). Currently, only `constraints.txt` and `requirements.txt` are supported.
 * `--output (-o)`: The name of the output file.  If omitted, print to standard output.
 * `--without`: The dependency groups to ignore when exporting.
 * `--with`: The optional dependency groups to include when exporting.

src/poetry_plugin_export/command.py

@@ -15,7 +15,8 @@ class ExportCommand(GroupCommand):
         option(
             "format",
             "f",
-            "Format to export to. Currently, only requirements.txt is supported.",
+            "Format to export to. Currently, only constraints.txt and requirements.txt"
+            " are supported.",
             flag=False,
             default=Exporter.FORMAT_REQUIREMENTS_TXT,
         ),

src/poetry_plugin_export/exporter.py

@@ -2,6 +2,7 @@
 
 import urllib.parse
 
+from functools import partialmethod
 from typing import TYPE_CHECKING
 from typing import Iterable
 
@@ -23,10 +24,14 @@ class Exporter:
     Exporter class to export a lock file to alternative formats.
     """
 
+    FORMAT_CONSTRAINTS_TXT = "constraints.txt"
     FORMAT_REQUIREMENTS_TXT = "requirements.txt"
     ALLOWED_HASH_ALGORITHMS = ("sha256", "sha384", "sha512")
 
-    EXPORT_METHODS = {FORMAT_REQUIREMENTS_TXT: "_export_requirements_txt"}
+    EXPORT_METHODS = {
+        FORMAT_CONSTRAINTS_TXT: "_export_constraints_txt",
+        FORMAT_REQUIREMENTS_TXT: "_export_requirements_txt",
+    }
 
     def __init__(self, poetry: Poetry) -> None:
         self._poetry = poetry
@@ -71,7 +76,9 @@ def export(self, fmt: str, cwd: Path, output: IO | str) -> None:
 
         getattr(self, self.EXPORT_METHODS[fmt])(cwd, output)
 
-    def _export_requirements_txt(self, cwd: Path, output: IO | str) -> None:
+    def _export_generic_txt(
+        self, cwd: Path, output: IO | str, with_extras: bool, allow_editable: bool
+    ) -> None:
         from poetry.core.packages.utils.utils import path_to_url
 
         indexes = set()
@@ -90,10 +97,18 @@ def _export_requirements_txt(self, cwd: Path, output: IO | str) -> None:
         ):
             line = ""
 
+            if not with_extras:
+                dependency_package = dependency_package.without_features()
+
             dependency = dependency_package.dependency
             package = dependency_package.package
 
             if package.develop:
+                if not allow_editable:
+                    raise RuntimeError(
+                        f"{package.pretty_name} is locked in develop (editable) mode,"
+                        " which is incompatible with the constraints.txt format."
+                    )
                 line += "-e "
 
             requirement = dependency.to_pep_508(with_extras=False)
@@ -182,12 +197,16 @@ def _export_requirements_txt(self, cwd: Path, output: IO | str) -> None:
 
             content = indexes_header + "\n" + content
 
-        self._output(content, cwd, output)
-
-    def _output(self, content: str, cwd: Path, output: IO | str) -> None:
         if isinstance(output, IO):
             output.write(content)
         else:
-            filepath = cwd / output
-            with filepath.open("w", encoding="utf-8") as f:
-                f.write(content)
+            with (cwd / output).open("w", encoding="utf-8") as txt:
+                txt.write(content)
+
+    _export_constraints_txt = partialmethod(
+        _export_generic_txt, with_extras=False, allow_editable=False
+    )
+
+    _export_requirements_txt = partialmethod(
+        _export_generic_txt, with_extras=True, allow_editable=True
+    )

tests/test_exporter.py

@@ -664,7 +664,7 @@ def test_exporter_can_export_requirements_txt_with_standard_packages_and_sorted_
     assert content == expected
 
 
-def test_exporter_requirements_txt_with_standard_packages_and_hashes_disabled(
+def test_exporter_can_export_requirements_txt_with_standard_packages_and_hashes_disabled(  # noqa: E501
     tmp_dir: str, poetry: Poetry
 ) -> None:
     poetry.locker.mock_lock_data(  # type: ignore[attr-defined]
@@ -2479,6 +2479,137 @@ def test_exporter_omits_unwanted_extras(
     assert io.fetch_output() == "\n".join(expected) + "\n"
 
 
+@pytest.mark.parametrize(
+    ["fmt", "expected"],
+    [
+        (
+            "constraints.txt",
+            [
+                f"bar==4.5.6 ; {MARKER_PY}",
+                f"baz==7.8.9 ; {MARKER_PY}",
+                f"foo==1.2.3 ; {MARKER_PY}",
+            ],
+        ),
+        (
+            "requirements.txt",
+            [
+                f"bar==4.5.6 ; {MARKER_PY}",
+                f"bar[baz]==4.5.6 ; {MARKER_PY}",
+                f"baz==7.8.9 ; {MARKER_PY}",
+                f"foo==1.2.3 ; {MARKER_PY}",
+            ],
+        ),
+    ],
+)
+def test_exporter_omits_and_includes_extras_for_txt_formats(
+    tmp_dir: str, poetry: Poetry, fmt: str, expected: list[str]
+) -> None:
+    poetry.locker.mock_lock_data(  # type: ignore[attr-defined]
+        {
+            "package": [
+                {
+                    "name": "foo",
+                    "version": "1.2.3",
+                    "category": "main",
+                    "optional": False,
+                    "python-versions": "*",
+                    "dependencies": {
+                        "bar": {
+                            "extras": ["baz"],
+                            "version": ">=0.1.0",
+                        }
+                    },
+                },
+                {
+                    "name": "bar",
+                    "version": "4.5.6",
+                    "category": "main",
+                    "optional": False,
+                    "python-versions": "*",
+                    "dependencies": {
+                        "baz": {
+                            "version": ">=0.1.0",
+                            "optional": True,
+                            "markers": "extra == 'baz'",
+                        }
+                    },
+                    "extras": {"baz": ["baz (>=0.1.0)"]},
+                },
+                {
+                    "name": "baz",
+                    "version": "7.8.9",
+                    "category": "main",
+                    "optional": False,
+                    "python-versions": "*",
+                },
+            ],
+            "metadata": {
+                "python-versions": "*",
+                "content-hash": "123456789",
+                "files": {"foo": [], "bar": [], "baz": []},
+            },
+        }
+    )
+    set_package_requires(poetry)
+
+    exporter = Exporter(poetry)
+    exporter.export(fmt, Path(tmp_dir), "exported.txt")
+
+    with (Path(tmp_dir) / "exported.txt").open(encoding="utf-8") as f:
+        content = f.read()
+
+    assert content == "\n".join(expected) + "\n"
+
+
+def test_exporter_raises_exception_for_constraints_txt_with_editable_packages(
+    tmp_dir: str, poetry: Poetry
+) -> None:
+    poetry.locker.mock_lock_data(  # type: ignore[attr-defined]
+        {
+            "package": [
+                {
+                    "name": "foo",
+                    "version": "1.2.3",
+                    "category": "main",
+                    "optional": False,
+                    "python-versions": "*",
+                    "source": {
+                        "type": "git",
+                        "url": "https://github.com/foo/foo.git",
+                        "reference": "123456",
+                    },
+                    "develop": True,
+                },
+                {
+                    "name": "bar",
+                    "version": "4.5.6",
+                    "category": "main",
+                    "optional": False,
+                    "python-versions": "*",
+                    "source": {
+                        "type": "directory",
+                        "url": "tests/fixtures/sample_project",
+                        "reference": "",
+                    },
+                    "develop": True,
+                },
+            ],
+            "metadata": {
+                "python-versions": "*",
+                "content-hash": "123456789",
+                "files": {"foo": [], "bar": []},
+            },
+        }
+    )
+    set_package_requires(poetry)
+
+    with pytest.raises(RuntimeError):
+        exporter = Exporter(poetry)
+        exporter.export("constraints.txt", Path(tmp_dir), "constraints.txt")
+
+    assert not (Path(tmp_dir) / "constraints.txt").exists()
+
+
 def test_exporter_respects_package_sources(tmp_dir: str, poetry: Poetry) -> None:
     poetry.locker.mock_lock_data(  # type: ignore[attr-defined]
         {