feat: add confirmation step

src/poetry/config/config_source.py

@@ -39,32 +39,46 @@ class ConfigSourceMigration:
     new_key: str | None
     value_migration: dict[Any, Any] = dataclasses.field(default_factory=dict)
 
-    def apply(self, config_source: ConfigSource, io: IO | None = None) -> None:
+    def dry_run(self, config_source: ConfigSource, io: IO | None = None) -> bool:
         io = io or NullIO()
 
         try:
             old_value = config_source.get_property(self.old_key)
         except PropertyNotFoundError:
-            return
+            return False
 
         new_value = (
             self.value_migration[old_value] if self.value_migration else old_value
         )
 
-        config_source.remove_property(self.old_key)
-
         msg = f"<c1>{self.old_key}</c1> = <c2>{json.dumps(old_value)}</c2>"
 
         if self.new_key is not None and new_value is not UNSET:
             msg += f" -> <c1>{self.new_key}</c1> = <c2>{json.dumps(new_value)}</c2>"
-            config_source.add_property(self.new_key, new_value)
         elif self.new_key is None:
             msg += " -> <c1>Removed from config</c1>"
         elif self.new_key and new_value is UNSET:
             msg += f" -> <c1>{self.new_key}</c1> = <c2>Not explicit set</c2>"
 
         io.write_line(msg)
 
+        return True
+
+    def apply(self, config_source: ConfigSource) -> None:
+        try:
+            old_value = config_source.get_property(self.old_key)
+        except PropertyNotFoundError:
+            return
+
+        new_value = (
+            self.value_migration[old_value] if self.value_migration else old_value
+        )
+
+        config_source.remove_property(self.old_key)
+
+        if self.new_key is not None and new_value is not UNSET:
+            config_source.add_property(self.new_key, new_value)
+
 
 def drop_empty_config_category(
     keys: list[str], config: dict[Any, Any]

src/poetry/console/commands/config.py

@@ -357,9 +357,22 @@ def _migrate(self) -> None:
 
         config_source = FileConfigSource(config_file)
 
-        self.io.write_line("Starting config migration ...")
+        self.io.write_line("Checking for required migrations ...")
 
-        for migration in CONFIG_MIGRATIONS:
-            migration.apply(config_source, io=self.io)
+        required_migrations = [
+            migration
+            for migration in CONFIG_MIGRATIONS
+            if migration.dry_run(config_source, io=self.io)
+        ]
 
-        self.io.write_line("Config migration successfully done.")
+        if not required_migrations:
+            self.io.write_line("Already up to date.")
+            return
+
+        if not self.io.is_interactive() or self.confirm(
+            "Proceed with migration?: ", False
+        ):
+            for migration in required_migrations:
+                migration.apply(config_source)
+
+            self.io.write_line("Config migration successfully done.")

tests/console/commands/test_config.py

@@ -569,32 +569,54 @@ def test_config_solver_lazy_wheel(
     assert not repo._lazy_wheel
 
 
+current_config = """\
+[experimental]
+system-git-client = true
+
+[virtualenvs]
+prefer-active-python = false
+"""
+
+config_migrated = """\
+system-git-client = true
+
+[virtualenvs]
+use-poetry-python = true
+"""
+
+
+@pytest.mark.parametrize(
+    ["proceed", "expected_config"],
+    [
+        ("yes", config_migrated),
+        ("no", current_config),
+    ],
+)
 def test_config_migrate(
-    tester: CommandTester, mocker: MockerFixture, tmp_path: Path
+    proceed: str,
+    expected_config: str,
+    tester: CommandTester,
+    mocker: MockerFixture,
+    tmp_path: Path,
 ) -> None:
     config_dir = tmp_path / "config"
     mocker.patch("poetry.locations.CONFIG_DIR", config_dir)
 
     config_file = Path(config_dir / "config.toml")
-    config_data = textwrap.dedent("""\
-    [experimental]
-    system-git-client = true
-
-    [virtualenvs]
-    prefer-active-python = false
-    """)
     with config_file.open("w") as fh:
-        fh.write(config_data)
-
-    tester.execute("--migrate")
+        fh.write(current_config)
 
-    expected_config = textwrap.dedent("""\
-    system-git-client = true
+    tester.execute("--migrate", inputs=proceed)
 
-    [virtualenvs]
-    use-poetry-python = true
+    expected_output = textwrap.dedent("""\
+    Checking for required migrations ...
+    experimental.system-git-client = true -> system-git-client = true
+    virtualenvs.prefer-active-python = false -> virtualenvs.use-poetry-python = true
     """)
 
+    output = tester.io.fetch_output()
+    assert output.startswith(expected_output)
+
     with config_file.open("r") as fh:
         assert fh.read() == expected_config
 
@@ -612,7 +634,7 @@ def test_config_migrate_local_config(tester: CommandTester, poetry: Poetry) -> N
     with local_config.open("w") as fh:
         fh.write(config_data)
 
-    tester.execute("--migrate --local")
+    tester.execute("--migrate --local", inputs="yes")
 
     expected_config = textwrap.dedent("""\
         system-git-client = true
@@ -629,4 +651,4 @@ def test_config_migrate_local_config_should_raise_if_not_found(
     tester: CommandTester,
 ) -> None:
     with pytest.raises(RuntimeError, match="No local config file found"):
-        tester.execute("--migrate --local")
+        tester.execute("--migrate --local", inputs="yes")