Use a short SPDX license header for LLM-centered files by Dev-iL · Pull Request #1489 · apache/hamilton

Dev-iL · 2026-02-22T13:25:49Z

Following the approach from apache/airflow#62073 and apache/airflow#62145, files intended for LLM/agent consumption (not distributed in releases) now use a minimal SPDX license identifier instead of the full Apache 2.0 header - for LLM token efficiency.

See also:
https://lists.apache.org/thread/j1tn63r2lf13v3d1tnnqff8fkcl4nx53

Changes

Mark the .github folder as export-ignore.
Add a short and long license templates.
Add pre-commit hooks to ensure the right license header exists in every file.
Add missing license headers to two PR templates.

How I tested this

Hooks pass locally.

Notes

Checklist

PR has an informative and human-readable title (this will be pulled into the release notes)
Changes are limited to a single goal (no scope creep)
Code passed the pre-commit check & code is left cleaner/nicer than when first encountered.
Any change in functionality is tested
New functions are documented (with a description, list of inputs, and expected output)
Placeholder code is flagged / future TODOs are captured in comments
Project documentation has been updated if adding/changing functionality.

dev_tools/language_server/tests/conftest.py

dev_tools/language_server/tests/ls_setup.py

scripts/add_license_headers.py

scripts/check_license_headers.py

skrawcz · 2026-02-24T06:39:01Z

.github/workflows/hamilton-lsp.yml

-    - name: Check for missing Apache 2 license headers
-      run: python3 scripts/check_license_headers.py
-      working-directory: ${{ github.workspace }}


why remove?

This answers all similar comments:

After the proposed change, license headers are being enforced by pre-commit hooks. This approach has several benefits:

Contributors can tell there's an issue before getting to ci

Coverage isn't lost since hooks should run on ci anyway as part of static checks

No need to maintain license enforcement scripts

Hooks were more thorough and detected missing licenses that the ci missed

Whereas the main downside is it's somewhat harder to customize if a specific file requires special treatment.

issue is people submit without running pre-commit hooks :(

The assumption was that the hooks run on CI too. It's just that instead of a custom script we use a hook - which is more standard.

Can you add that to CI then?

It already runs as part of the "Unit Tests" job's "check linting with prek" stage. I'll move this to a separate "Static checks" job for better visibility.

skrawcz · 2026-03-08T06:17:57Z

NOTICE

+This product includes test code vendored from pygls
+(https://github.com/openlawlibrary/pygls):
+  Copyright (c) Open Law Library. All rights reserved.
+  Licensed under the Apache License, Version 2.0.
+
+  Original work in conftest.py:
+  Copyright 2017 Palantir Technologies, Inc.
+  Licensed under the MIT License.


should this be here? or under the LSP package notice? I think the LSP package, since this is related to the source distribution of that, no?

According to the ASF guidelines,

LICENSE and NOTICE files belong at the top level of the source tree.

I'm not sure how this applies to monorepos though. Will investigate...

- Mark .github as export-ignore in .gitattributes - Add short and long license templates for pre-commit hooks - Add pre-commit hooks to enforce license headers (replaces CI scripts) - Delete scripts/add_license_headers.py and scripts/check_license_headers.py - Remove CI license check step from hamilton-lsp workflow - Fix inconsistent license header indentation in several files - Add missing license headers to PR templates - Add vendored code attributions (Open Law Library, Palantir) to NOTICE file - Exclude contrib/docs/ from markdown license hook (Docusaurus frontmatter)

pjfanning · 2026-03-08T10:16:51Z

dev_tools/language_server/tests/conftest.py

-# distributed under the License is distributed on an "AS IS" BASIS,        #
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. #
-# See the License for the specific language governing permissions and      #
-# limitations under the License.                                           #


You can't remove license headers from 3rd party origin files.

This should be reverted and we should still update https://github.com/SummitSG-LLC/hamilton/blob/8fa698904c772a6738f7531c7fa56f62753fa325/dev_tools/language_server/LICENSE to mention this conftest.py file

It's unclear to me how this file should end up - do we keep only the original copyright notice or have both one under the other?

don't remove any 3rd party code header - it's basically a rule of the ASF - you need to come up with a strong justification for it - there is an open issue for this

#1363

And that issue can't continue to be ignored. We need to at least update our LICENSE file to mention any 3rd party code.

For now I kept the old header and excluded this file from the hook.

ok - if we agree the code does not contain anything that requires the old Palantir copyright then it is ok to remove it

dev_tools/language_server/NOTICE

Dev-iL · 2026-03-08T10:23:47Z

.claude-plugin/skills/core/SKILL.md

 ---
+<!-- SPDX-License-Identifier: Apache-2.0 -->


@potiuk I configured the hooks to accept the license being below the frontmatter using:

# .pre-commit-config.yaml - id: insert-license ... - --detect-license-in-X-top-lines - '8'

In case this comes in handy in Airflow too...

ok to proceed

Dev-iL requested review from pjfanning, potiuk and skrawcz February 22, 2026 13:25

Dev-iL force-pushed the 2602/spdx branch from 9af762d to 83829f2 Compare February 22, 2026 13:47

Dev-iL commented Feb 22, 2026

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Dev-iL commented Feb 22, 2026

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Dev-iL force-pushed the 2602/spdx branch from 83829f2 to 3d56e35 Compare February 22, 2026 14:14

skrawcz reviewed Feb 24, 2026

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skrawcz reviewed Feb 24, 2026

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Dev-iL force-pushed the 2602/spdx branch 3 times, most recently from 8f6cdd6 to c1f2647 Compare March 6, 2026 18:39

skrawcz reviewed Mar 8, 2026

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Dev-iL force-pushed the 2602/spdx branch from c1f2647 to d86280f Compare March 8, 2026 06:31

Dev-iL added 2 commits March 8, 2026 11:55

Specify hook stages explicitly

8fa6989

Dev-iL force-pushed the 2602/spdx branch from d86280f to 8fa6989 Compare March 8, 2026 09:55

pjfanning previously requested changes Mar 8, 2026

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Dev-iL commented Mar 8, 2026

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Fix copyright notices

8be2028

Dev-iL requested a review from pjfanning March 8, 2026 10:35

Dev-iL mentioned this pull request Mar 8, 2026

review license setup on dev_tools/language_server/tests/conftest.py #1363

Open

pjfanning mentioned this pull request Mar 18, 2026

Update LICENSE with conftest.py licensing details #1513

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Dev-iL commented Feb 22, 2026

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Dev-iL Feb 24, 2026 •

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