Support custom LICENSE option & new default license Apache-2.0

Author: dalito

CHANGELOG.md

@@ -17,6 +17,20 @@ The format is inspired by [Keep a Changelog](https://keepachangelog.com/en/1.1.0
 
 [Full changelog](https://github.com/linkml/linkml-project-copier/compare/v0.4.1...main)
 
+### Changed
+
+- Default `license` is now `Apache-2.0` (was `MIT`). #151
+
+### Added
+
+- New `existing_license_file` prompt: when set to the path of a license file
+  already present in the project (e.g. `LICENSE.md`, `LICENSE.txt`), the
+  template skips generating a new `LICENSE` and points `license-files` in
+  `pyproject.toml` at the provided file. The `license` prompt then defaults to
+  `Custom` (recorded as the PEP 639 SPDX identifier `LicenseRef-Custom`),
+  signalling "see the license file"; the user can override with a specific
+  SPDX identifier if they know it. #151
+
 ### Fixed
 
 - Fix `uv tool` command that includes jinja2-time into copier. #90

README.md

@@ -75,6 +75,11 @@ The `--trust` option is needed because the template uses the jinja_extension `ji
 You will be prompted a few questions.
 The defaults are fine for most projects, but pick the name for your project carefully as it will also be used as project name on GitHub.
 
+If you are applying the template to an existing project that already has a license file (e.g. `LICENSE.md`, `LICENSE.txt`), answer the `existing_license_file` prompt with its path.
+The template will then leave your file untouched, skip generating a new `LICENSE`, and point `license-files` in `pyproject.toml` at the file you named.
+The `license` prompt will default to `Custom` in that case, recorded as the PEP 639 identifier `LicenseRef-Custom`; override it if you know the file's actual SPDX license.
+The default license for new projects is `Apache-2.0`.
+
 It is also possible to use non-default branches or specific tags via `--vcs-ref` which is useful when developing the template:
 
 ```shell

copier.yaml

@@ -46,17 +46,31 @@ project_description:
   type: str
   default: This is the project description.
 
+existing_license_file:
+  help: |
+    If your project already has a license file, give its path relative to the
+    project root (e.g. LICENSE.md, LICENSE.txt). Leave empty to generate a new
+    LICENSE file from the license chosen below. The SPDX identifier is
+    recorded in pyproject.toml either way.
+  type: str
+  default: ""
+
 license:
-  help: Which license do you want for your project?
+  help: |
+    Which license do you want for your project? Pick "Custom" if you supplied an
+    existing license file above whose content does not match any of the listed
+    SPDX licenses; that records the PEP 639 identifier `LicenseRef-Custom` in
+    pyproject.toml, signalling "see the license file".
   type: str
   choices:
-    - MIT
-    - BSD-3-Clause
-    - Apache-2.0
-    - MPL-2.0
-    - LGPL-3.0-only
-    - GPL-3.0-only
-  default: MIT
+    MIT: MIT
+    BSD-3-Clause: BSD-3-Clause
+    Apache-2.0: Apache-2.0
+    MPL-2.0: MPL-2.0
+    LGPL-3.0-only: LGPL-3.0-only
+    GPL-3.0-only: GPL-3.0-only
+    Custom: LicenseRef-Custom
+  default: "{{ 'LicenseRef-Custom' if existing_license_file else 'Apache-2.0' }}"
 
 copyright_year:
   help: The year of the first release

template/pyproject.toml.jinja

@@ -9,7 +9,7 @@ authors = [
   {name = "{{full_name}}", email = "{{email}}"},
 ]
 license = "{{license}}"
-license-files = ["LICENSE"]
+license-files = ["{{ existing_license_file or 'LICENSE' }}"]
 readme = "README.md"
 requires-python = ">=3.10,<4.0"
 dynamic = ["version"]

template/LICENSE.jinja …_license_file %}LICENSE{% endif %}.jinjatemplate/LICENSE.jinja renamed to template/{% if not existing_license_file %}LICENSE{% endif %}.jinja template/LICENSE.jinja renamed to template/{% if not existing_license_file %}LICENSE{% endif %}.jinja

@@ -19,6 +19,7 @@
     "full_name": "Test User",
     "github_org": "test-org",
     "project_description": "A test project.",
+    "existing_license_file": "",
     "license": "MIT",
     "copyright_year": "2025",
     "add_example": True,

tests/helpers.py

@@ -4,6 +4,10 @@
 
 import sys
 
+from copier import run_copy
+
+from tests.helpers import DEFAULT_DATA, TEMPLATE_ROOT
+
 if sys.version_info >= (3, 11):
     import tomllib
 else:
@@ -41,3 +45,71 @@ def test_pyproject_license_field(self, license_project):
             (project_path / "pyproject.toml").read_text(encoding="utf-8")
         )
         assert pyproject["project"]["license"] == license_name
+
+
+class TestApacheDefault:
+    """The default license when the user accepts all defaults is Apache-2.0."""
+
+    def test_default_is_apache(self, tmp_path):
+        # Build data without a `license` key so copier falls back to the
+        # question's default (Apache-2.0).
+        data = {k: v for k, v in DEFAULT_DATA.items() if k != "license"}
+        run_copy(
+            str(TEMPLATE_ROOT),
+            tmp_path,
+            data=data,
+            defaults=True,
+            unsafe=True,
+            vcs_ref="HEAD",
+        )
+        license_text = (tmp_path / "LICENSE").read_text(encoding="utf-8")
+        assert LICENSE_MARKERS["Apache-2.0"] in license_text
+        pyproject = tomllib.loads(
+            (tmp_path / "pyproject.toml").read_text(encoding="utf-8")
+        )
+        assert pyproject["project"]["license"] == "Apache-2.0"
+
+
+class TestExistingLicenseFile:
+    """When existing_license_file is set, no LICENSE is generated, the user's
+    existing file is preserved, pyproject records `LicenseRef-Custom` and
+    points `license-files` at the user's file."""
+
+    def _data_with_existing(self, filename: str) -> dict:
+        # Omit `license` so copier computes the dynamic default
+        # ("LicenseRef-Custom" when existing_license_file is set).
+        data = {k: v for k, v in DEFAULT_DATA.items() if k != "license"}
+        data["existing_license_file"] = filename
+        return data
+
+    def test_no_license_generated_when_existing_file_named(self, tmp_path):
+        data = self._data_with_existing("LICENSE.md")
+        run_copy(
+            str(TEMPLATE_ROOT),
+            tmp_path,
+            data=data,
+            defaults=True,
+            unsafe=True,
+            vcs_ref="HEAD",
+        )
+        assert not (tmp_path / "LICENSE").exists()
+        pyproject = tomllib.loads(
+            (tmp_path / "pyproject.toml").read_text(encoding="utf-8")
+        )
+        assert pyproject["project"]["license"] == "LicenseRef-Custom"
+        assert pyproject["project"]["license-files"] == ["LICENSE.md"]
+
+    def test_preexisting_license_md_is_preserved(self, tmp_path):
+        sentinel = "MY EXISTING LICENSE — DO NOT TOUCH\n"
+        (tmp_path / "LICENSE.md").write_text(sentinel, encoding="utf-8")
+        data = self._data_with_existing("LICENSE.md")
+        run_copy(
+            str(TEMPLATE_ROOT),
+            tmp_path,
+            data=data,
+            defaults=True,
+            unsafe=True,
+            vcs_ref="HEAD",
+        )
+        assert not (tmp_path / "LICENSE").exists()
+        assert (tmp_path / "LICENSE.md").read_text(encoding="utf-8") == sentinel