# Setting a known commit ID in the CTest Update Step for source tarballs

**URL:** https://discourse.cmake.org/t/setting-a-known-commit-id-in-the-ctest-update-step-for-source-tarballs/15664
**Category:** Usage
**Created:** [May 26, 2026, 2:49pm UTC](https://discourse.cmake.org/t/setting-a-known-commit-id-in-the-ctest-update-step-for-source-tarballs/15664 "2026-05-26T14:49:06Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![hebasto](https://discourse.cmake.org/user_avatar/discourse.cmake.org/hebasto/32/4713_2.png) [@hebasto](https://discourse.cmake.org/u/hebasto)
#### Post date: [May 26, 2026, 2:49pm UTC](https://discourse.cmake.org/t/setting-a-known-commit-id-in-the-ctest-update-step-for-source-tarballs/15664/1 "2026-05-26T14:49:07Z")

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Hi,

One of the pipelines in our CI downloads a source tarball of the master branch (generated via `git archive`) and extracts the top commit hash from it. Because it’s a tarball, there is no actual `.git` directory present.

How can I configure the CTest Update Step to simply set the revision to this known commit ID?

I tried setting the `CTEST_UPDATE_VERSION_OVERRIDE` variable, but that approach doesn’t seem to work. Does anyone know the proper way to handle this?