feat(init): allow manim init project into an existing folder

manim/cli/init/commands.py

@@ -115,31 +115,40 @@ def project(default_settings: bool, **kwargs: Any) -> None:
         default="Default",
     )
 
-    if project_name.is_dir():
-        console.print(
-            f"\nFolder [red]{project_name}[/red] exists. Please type another name\n",
-        )
-    else:
-        project_name.mkdir()
-        new_cfg: dict[str, Any] = {}
-        new_cfg_path = Path.resolve(project_name / "manim.cfg")
-
-        if not default_settings:
-            for key, value in CFG_DEFAULTS.items():
-                if key == "scene_names":
-                    new_cfg[key] = template_name + "Template"
-                elif key == "resolution":
-                    new_cfg[key] = select_resolution()
-                else:
-                    new_cfg[key] = click.prompt(f"\n{key}", default=value)
-
-            console.print("\n", new_cfg)
-            if click.confirm("Do you want to continue?", default=True, abort=True):
-                copy_template_files(project_name, template_name)
-                update_cfg(new_cfg, new_cfg_path)
-        else:
+    # Initializing into an existing (e.g. ``uv init``ed) folder is allowed;
+    # only the files we would create can conflict, so confirm before
+    # overwriting them instead of refusing outright.
+    conflicts = [
+        name for name in ("manim.cfg", "main.py") if (project_name / name).exists()
+    ]
+    if conflicts and not click.confirm(
+        f"\nFolder [red]{project_name}[/red] already contains "
+        f"{', '.join(conflicts)}. Overwrite?",
+        default=False,
+    ):
+        console.print("\nAborted; existing files were left untouched.\n")
+        return
+
+    project_name.mkdir(parents=True, exist_ok=True)
+    new_cfg: dict[str, Any] = {}
+    new_cfg_path = Path.resolve(project_name / "manim.cfg")
+
+    if not default_settings:
+        for key, value in CFG_DEFAULTS.items():
+            if key == "scene_names":
+                new_cfg[key] = template_name + "Template"
+            elif key == "resolution":
+                new_cfg[key] = select_resolution()
+            else:
+                new_cfg[key] = click.prompt(f"\n{key}", default=value)
+
+        console.print("\n", new_cfg)
+        if click.confirm("Do you want to continue?", default=True, abort=True):
             copy_template_files(project_name, template_name)
-            update_cfg(CFG_DEFAULTS, new_cfg_path)
+            update_cfg(new_cfg, new_cfg_path)
+    else:
+        copy_template_files(project_name, template_name)
+        update_cfg(CFG_DEFAULTS, new_cfg_path)
 
 
 @cloup.command(

tests/interface/test_commands.py

@@ -133,6 +133,43 @@ def test_manim_init_project(tmp_path):
         assert (Path(tmp_dir) / "testproject/manim.cfg").exists()
 
 
+def test_manim_init_project_existing_folder(tmp_path):
+    command = ["init", "project", "--default", "."]
+    runner = CliRunner()
+    with runner.isolated_filesystem(temp_dir=tmp_path) as tmp_dir:
+        # A pre-existing, non-conflicting folder should be usable.
+        (Path(tmp_dir) / "pyproject.toml").write_text("")
+        result = runner.invoke(main, command, prog_name="manim", input="Default\n")
+        assert not result.exception
+        assert (Path(tmp_dir) / "main.py").exists()
+        assert (Path(tmp_dir) / "manim.cfg").exists()
+
+
+def test_manim_init_project_conflicting_files_declined(tmp_path):
+    command = ["init", "project", "--default", "."]
+    runner = CliRunner()
+    with runner.isolated_filesystem(temp_dir=tmp_path) as tmp_dir:
+        # Declining the overwrite prompt must leave the conflicting file intact.
+        (Path(tmp_dir) / "main.py").write_text("# keep me\n")
+        result = runner.invoke(main, command, prog_name="manim", input="Default\nn\n")
+        assert not result.exception
+        assert "already contains" in result.output
+        assert (Path(tmp_dir) / "main.py").read_text() == "# keep me\n"
+        assert not (Path(tmp_dir) / "manim.cfg").exists()
+
+
+def test_manim_init_project_conflicting_files_overwritten(tmp_path):
+    command = ["init", "project", "--default", "."]
+    runner = CliRunner()
+    with runner.isolated_filesystem(temp_dir=tmp_path) as tmp_dir:
+        # Confirming the overwrite prompt replaces the conflicting file.
+        (Path(tmp_dir) / "main.py").write_text("# keep me\n")
+        result = runner.invoke(main, command, prog_name="manim", input="Default\ny\n")
+        assert not result.exception
+        assert (Path(tmp_dir) / "main.py").read_text() != "# keep me\n"
+        assert (Path(tmp_dir) / "manim.cfg").exists()
+
+
 def test_manim_init_scene(tmp_path):
     command_named = ["init", "scene", "NamedFileTestScene", "my_awesome_file.py"]
     command_unnamed = ["init", "scene", "DefaultFileTestScene"]