Remove "License :: ..." classifiers from pyproject.toml examples

tomalrussell · tomalrussell · commit 363d570a5e5a · 2025-07-31T18:00:47.000+01:00
Update use of "license = ..." key to use short reference. See #557 for discussion
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
@@ -383,7 +383,6 @@ Classifiers are just a list of plain strings
 ```toml
 classifiers = [
     "Programming Language :: Python :: 3",
-    "License :: OSI Approved :: BSD License",
     "Operating System :: OS Independent",
 ]
 ```
diff --git a/examples/extension-hatch/pyproject.toml b/examples/extension-hatch/pyproject.toml
@@ -16,8 +16,8 @@ maintainers = [
 description = "An example Python package used to support Python packaging tutorials"
 keywords = ["pyOpenSci", "python packaging"]
 readme = "README"
+license = "BSD-3-Clause"
 classifiers = [
     "Programming Language :: Python :: 3",
-    "License :: OSI Approved :: BSD License",
     "Operating System :: OS Independent",
 ]
diff --git a/examples/pure-hatch/pyproject.toml b/examples/pure-hatch/pyproject.toml
@@ -13,9 +13,9 @@ maintainers = [
 description = "An example Python package used to support Python packaging tutorials"
 keywords = ["pyOpenSci", "python packaging"]
 readme = "README.md"
+license = "BSD-3-Clause"
 classifiers = [
     "Programming Language :: Python :: 3",
-    "License :: OSI Approved :: BSD License",
     "Operating System :: OS Independent",
 ]
 dependencies = [
diff --git a/examples/pure-setuptools/pyproject.toml b/examples/pure-setuptools/pyproject.toml
@@ -13,9 +13,9 @@ maintainers = [
 description = "An example Python package used to support Python packaging tutorials"
 keywords = ["pyOpenSci", "python packaging"]
 readme = "README.md"
+license = "BSD-3-Clause"
 classifiers = [
     "Programming Language :: Python :: 3",
-    "License :: OSI Approved :: BSD License",
     "Operating System :: OS Independent",
 ]
 dependencies = [
diff --git a/package-structure-code/python-package-distribution-files-sdist-wheel.md b/package-structure-code/python-package-distribution-files-sdist-wheel.md
@@ -53,7 +53,7 @@ dependencies = [
 
 2. When the build tool creates your package distribution file (the file that you publish on PyPI), it also creates a METADATA file which PyPI can read and use to help users find your package. For example:
 
-- The `classifiers = ` section of your `[project]` table in the pyproject.toml file provides information that users on PyPI can use to filter for packages that contain specific licenses or that support specific versions of python.
+- The `classifiers = ` section of your `[project]` table in the pyproject.toml file provides information that users on PyPI can use to filter for packages that address different topics or that support specific versions of python.
 
 ```toml
 classifiers = [
@@ -63,7 +63,6 @@ classifiers = [
     # Indicate who your project is intended for
     "Intended Audience :: Developers",
     "Topic :: Software Development :: Build Tools",
-    "License :: OSI Approved :: MIT License",
     "Programming Language :: Python :: 3 :: Only",
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
diff --git a/tutorials/add-license-coc.md b/tutorials/add-license-coc.md
@@ -26,13 +26,13 @@ In this lesson you will learn:
 A license contains legal language about how users can use and reuse your software. To set the `LICENSE` for your project, you:
 
 1. Create a `LICENSE` file in your project directory that specifies the license that you choose for your package.
-2. Reference that file in your `pyproject.toml` data where metadata are set.
+2. Reference that license in your `pyproject.toml` data where metadata are set.
 
-By adding the `LICENSE` file to your `pyproject.toml` file, the `LICENSE` will be included in your package's metadata which is used to populate your package's PyPI landing page. The `LICENSE` is also used in your GitHub repository's landing page interface.
+By adding the license reference to your `pyproject.toml` file, the license will be included in your package's metadata which is used to populate your package's PyPI landing page. The `LICENSE` is also used in your GitHub repository's landing page interface.
 
 ### What license should you use?
 
-We suggest that you use a permissive license that accommodates the other most commonly used licenses in the scientific Python ecosystem (MIT[^mit] and BSD-3[^bsd3]). If you are unsure, use MIT given it's the generally recommended
+We suggest that you use a permissive license that accommodates the other most commonly used licenses in the scientific Python ecosystem (MIT[^mit] and BSD-3-Clause[^bsd3]). If you are unsure, use MIT given it's the generally recommended
 license on [choosealicense.com](https://choosealicense.com/).
 
 :::{admonition} Licenses for the scientific Python ecosystem
diff --git a/tutorials/create-python-package.md b/tutorials/create-python-package.md
@@ -265,7 +265,6 @@ readme = {"file" = "README.md", "content-type" = "text/markdown"}
 classifiers = [
     "Development Status :: 2 - Pre-Alpha",
     "Intended Audience :: Science/Research",
-    "License :: OSI Approved :: MIT License",
     "Operating System :: OS Independent",
     "Programming Language :: Python :: 3 :: Only",
 ]
diff --git a/tutorials/pyproject-toml.md b/tutorials/pyproject-toml.md
@@ -272,8 +272,10 @@ you want to have listed as authors and maintainers on your PyPI landing page.
 ### Step 2: Add README and license
 
 In the previous lessons, you added both a [README.md](add-readme) file and a [LICENSE](add-license-coc) to your package repository.
-Once you have those files, you can add them to your pyproject.toml file as
-links following the example below.
+Once you have those files, you can refer to the README from your pyproject.toml file, and add a short reference to your LICENSE
+following the example below. 
+
+The reference to your license should use the [license expression syntax](https://packaging.python.org/en/latest/specifications/license-expression/), which can generally be a short name (with no spaces) for the license, such as "MIT", "BSD-3-Clause" or "Apache-2.0".
 
 {emphasize-lines="20-21"}
 ```toml
@@ -297,7 +299,7 @@ maintainers = [
   { name = "New Friend", email = "newbie@pyopensci.org" }
 ]
 readme = "README.md"
-license = {file = "LICENSE"}
+license = "MIT"
 ```
 ### Step 3: Specify Python version with `requires-python`
 
@@ -337,7 +339,7 @@ maintainers = [
   { name = "New Friend", email = "newbie@pyopensci.org" }
 ]
 readme = "README.md"
-license = {file = 'LICENSE'}
+license = "MIT"
 requires-python = ">=3.10"
 ```
 
@@ -409,7 +411,7 @@ maintainers = [
   { name = "New Friend", email = "newbie@pyopensci.org" }
 ]
 readme = "README.md"
-license = {file = 'LICENSE'}
+license = "MIT"
 requires-python = ">=3.10"
 
 dependencies = ["numpy>=1.0", "requests==10.1", "pandas", "pydantic>=1.7,<2"]
@@ -454,12 +456,11 @@ Review that list and add items below to your `pyproject.toml` file:
 - development status
 - intended audiences
 - topic
-- license and
 - programming language support
 
 The classifier key should look something like the example below. A few notes:
 
-- Your classifier values might be different depending upon the license you have selected for your package, your intended audience, development status of your package and the Python versions that you support
+- Your classifier values might be different depending upon your intended audience, development status of your package and the Python versions that you support
 - You can add as many classifiers as you wish as long as you use the [designated PyPI classifier values](https://PyPI.org/classifiers/).
 
 {emphasize-lines="26-34"}
@@ -484,7 +485,7 @@ maintainers = [
   { name = "New Friend", email = "newbie@pyopensci.org" }
 ]
 readme = "README.md"
-license = {file = 'LICENSE'}
+license = "MIT"
 requires-python = ">=3.10"
 
 dependencies = ["numpy>=1.0", "requests==10.1", "pandas", "pydantic>=1.7,<2"]
@@ -493,7 +494,6 @@ classifiers = [
     "Development Status :: 4 - Beta",
     "Intended Audience :: Developers",
     "Topic :: Software Development :: Build Tools",
-    "License :: OSI Approved :: MIT License",
     "Programming Language :: Python :: 3 :: Only",
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
@@ -534,7 +534,7 @@ maintainers = [
   { name = "New Friend", email = "newbie@pyopensci.org" }
 ]
 readme = "README.md"
-license = {file = 'LICENSE'}
+license = "MIT"
 requires-python = ">=3.10"
 
 dependencies = ["numpy>=1.0", "requests==10.1", "pandas", "pydantic>=1.7,<2"]
@@ -543,7 +543,6 @@ classifiers = [
     "Development Status :: 4 - Beta",
     "Intended Audience :: Developers",
     "Topic :: Software Development :: Build Tools",
-    "License :: OSI Approved :: MIT License",
     "Programming Language :: Python :: 3 :: Only",
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
@@ -585,7 +584,7 @@ maintainers = [
   { name = "New Friend", email = "newbie@pyopensci.org" }
 ]
 readme = "README.md"
-license = {file = 'LICENSE'}
+license = "MIT"
 requires-python = ">=3.10"
 
 dependencies = ["numpy>=1.0", "requests==10.1", "pandas", "pydantic>=1.7,<2"]
@@ -594,7 +593,6 @@ classifiers = [
     "Development Status :: 4 - Beta",
     "Intended Audience :: Developers",
     "Topic :: Software Development :: Build Tools",
-    "License :: OSI Approved :: MIT License",
     "Programming Language :: Python :: 3 :: Only",
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
@@ -650,9 +648,6 @@ classifiers = [
     "Intended Audience :: Developers",
     "Topic :: Software Development :: Build Tools",
 
-    # Pick your license (using syntax from the classifier page). We suggest MIT, BSD3 or Apache if you are corporate
-    "License :: OSI Approved :: MIT License",
-
     # Specify the Python versions ensuring that you indicate you support Python 3.
     # this is only for PyPI and other metadata associated with your package - for your users to see
     "Programming Language :: Python :: 3 :: Only", # BE sure to specify that you use python 3.x
@@ -665,7 +660,11 @@ dependencies = ["numpy>=1.0", "requests==10.1", "pandas", "pydantic>=1.7,<2"]
 # This is the metadata that pip reads to understand what versions your package supports
 requires-python = ">=3.10"
 readme = "README.md"
-license = { file = "LICENSE" }
+
+# Pick your license using license expression syntax specified here:
+# https://packaging.python.org/en/latest/specifications/license-expression/
+# We suggest MIT, BSD-3-Clause or Apache-2.0 if you are corporate
+license = "MIT"
 
 # Add urls for your home page, issue tracker and source code
 [project.urls] # Optional

Original file line number	Diff line number	Diff line change
`@@ -383,7 +383,6 @@ Classifiers are just a list of plain strings`
`383`	`383`	```toml
`384`	`384`	`classifiers = [`
`385`	`385`	`"Programming Language :: Python :: 3",`
`386`		`- "License :: OSI Approved :: BSD License",`
`387`	`386`	`"Operating System :: OS Independent",`
`388`	`387`	`]`
`389`	`388`	```
Original file line number	Diff line number	Diff line change
`@@ -265,7 +265,6 @@ readme = {"file" = "README.md", "content-type" = "text/markdown"}`
`265`	`265`	`classifiers = [`
`266`	`266`	`"Development Status :: 2 - Pre-Alpha",`
`267`	`267`	`"Intended Audience :: Science/Research",`
`268`		`- "License :: OSI Approved :: MIT License",`
`269`	`268`	`"Operating System :: OS Independent",`
`270`	`269`	`"Programming Language :: Python :: 3 :: Only",`
`271`	`270`	`]`