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

@@ -23,10 +23,14 @@ 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 +75,15 @@ def export(self, fmt: str, cwd: Path, output: IO | str) -> None:
 
         getattr(self, self.EXPORT_METHODS[fmt])(cwd, output)
 
+    def _export_constraints_txt(self, cwd: Path, output: IO | str) -> None:
+        return self._export_generic_txt(cwd, output, export_as_constraints=True)
+
     def _export_requirements_txt(self, cwd: Path, output: IO | str) -> None:
+        return self._export_generic_txt(cwd, output, export_as_constraints=False)
+
+    def _export_generic_txt(
+        self, cwd: Path, output: IO | str, export_as_constraints: bool
+    ) -> None:
         from poetry.core.packages.utils.utils import path_to_url
 
         indexes = set()
@@ -90,10 +102,18 @@ def _export_requirements_txt(self, cwd: Path, output: IO | str) -> None:
         ):
             line = ""
 
+            if export_as_constraints:
+                dependency_package = dependency_package.without_features()
+
             dependency = dependency_package.dependency
             package = dependency_package.package
 
             if package.develop:
+                if export_as_constraints:
+                    raise RuntimeError(
+                        f"{package.pretty_name} is configured for develop mode"
+                        " which is incompatible with the constraints format."
+                    )
                 line += "-e "
 
             requirement = dependency.to_pep_508(with_extras=False)

tests/test_exporter.py

@@ -107,6 +107,139 @@ def set_package_requires(poetry: Poetry, skip: set[str] | None = None) -> None:
     poetry._package = package
 
 
+def test_exporter_keeps_extras_for_requirements_txt(
+    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": "*",
+                    "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("requirements.txt", Path(tmp_dir), "requirements.txt")
+
+    with (Path(tmp_dir) / "requirements.txt").open(encoding="utf-8") as f:
+        content = f.read()
+
+    expected = f"""\
+bar==4.5.6 ; {MARKER_PY}
+bar[baz]==4.5.6 ; {MARKER_PY}
+baz==7.8.9 ; {MARKER_PY}
+foo==1.2.3 ; {MARKER_PY}
+"""
+
+    assert content == expected
+
+
+def test_exporter_removes_extras_for_constraints_txt(
+    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": "*",
+                    "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("constraints.txt", Path(tmp_dir), "constraints.txt")
+
+    with (Path(tmp_dir) / "constraints.txt").open(encoding="utf-8") as f:
+        content = f.read()
+
+    expected = f"""\
+bar==4.5.6 ; {MARKER_PY}
+baz==7.8.9 ; {MARKER_PY}
+foo==1.2.3 ; {MARKER_PY}
+"""
+
+    assert content == expected
+
+
 def test_exporter_can_export_requirements_txt_with_standard_packages(
     tmp_dir: str, poetry: Poetry
 ) -> None: