Allow wildcard argument for --extra

The goal is to make it easy to compile version locks for all runtime
dependencies in a way that is robust to human error. By using the
wildcard extra the risk of forgetting to list any extra is removed.

Since the expanded extras are needed when we look for the wildcard it
is moved to before the loop. This is OK because it does not depend on
the loop and nothing in the loop depends on its previous value.

piptools/scripts/compile.py

@@ -401,6 +401,8 @@ def cli(
     # Parsing/collecting initial requirements
     ###
 
+    extras = tuple(itertools.chain.from_iterable(ex.split(",") for ex in extras))
+
     constraints: List[InstallRequirement] = []
     setup_file_found = False
     for src_file in src_files:
@@ -442,6 +444,14 @@ def cli(
                     for req in metadata.get_all("Requires-Dist") or []
                 ]
             )
+            # Since "*" is not a valid extra there is no risk confusing an actual extra
+            # for the wildcard.
+            # https://peps.python.org/pep-0508/#grammar
+            if "*" in extras:
+                if len(extras) != 1:
+                    msg = "--extra=* only makes sense if it is the only --extra"
+                    raise click.BadParameter(msg)
+                extras = tuple(metadata.get_all("Provides-Extra"))
         else:
             constraints.extend(
                 parse_requirements(
@@ -452,8 +462,6 @@ def cli(
                 )
             )
 
-    extras = tuple(itertools.chain.from_iterable(ex.split(",") for ex in extras))
-
     if extras and not setup_file_found:
         msg = "--extra has effect only with setup.py and PEP-517 input formats"
         raise click.BadParameter(msg)

tests/test_cli_compile.py

@@ -2190,6 +2190,44 @@ def test_multiple_extras(fake_dists, runner, make_module, fname, content, extra_
     assert "extra ==" not in out.stderr
 
 
+@pytest.mark.network
+@pytest.mark.parametrize(("fname", "content"), METADATA_TEST_CASES)
+def test_wildcard_extras(fake_dists, runner, make_module, fname, content):
+    """
+    Test passing wildcard `--extra` includes all applicable extras.
+    """
+    meta_path = make_module(fname=fname, content=content)
+    out = runner.invoke(
+        cli,
+        [
+            "-n",
+            "--extra",
+            "*",
+            "--find-links",
+            fake_dists,
+            "--no-annotate",
+            "--no-emit-options",
+            "--no-header",
+            meta_path,
+        ],
+    )
+    assert out.exit_code == 0, out.stderr
+    assert (
+        dedent(
+            """\
+        small-fake-a==0.1
+        small-fake-b==0.2
+        small-fake-c==0.3
+        small-fake-d==0.4
+        small-fake-e==0.5
+        small-fake-f==0.6
+        Dry-run, so nothing updated.
+        """
+        )
+        == out.stderr
+    )
+
+
 def test_extras_fail_with_requirements_in(runner, tmpdir):
     """
     Test that passing `--extra` with `requirements.in` input file fails.