Hypothetical situation: Our organization developed closed-source commercial software that used open-source libraries whose terms only apply on redistribution. At some point, we decide to open-source our software but under a license that is incompatible with the aforementioned libraries. We rewrite those parts of our software so the latest revision no longer relies on any open-source libraries.

What happens when we publish our source-code repository?

  1. If our source-code history contains revisions where our software relied on the open-source libraries, does their licensing terms kick in? Or is the latest revision of the source-code repository the only thing relevant from a legal perspective?

  2. If the entire history is relevant, would truncating the source-code history (removing references to the open-source libraries) be sufficient to protect us?

  3. What about intellectual property? If past revisions infringed on someone's IP but the latest revision does not, are we still at risk? Would truncating history protect us?

  4. Broadly speaking, do past software revisions place us at legal risk from a copyright and/or IP perspective even if the latest revision does not infringe?

  • This suffers from the usual problem with hypothetical questions: an answer will depend on missing details. Just to name one: did you distribute aforementioned binaries to anyone?
    – MSalters
    Commented May 16, 2020 at 19:03
  • @MSalters This really is a hypothetical question. I've never had the good fortune of succeeding at any of my businesses so this problem has never come up. I assume that if I did distribute close-source binaries then infringement has taken place, whether I provide the source-code history or not. But what happens if I never distributed the binaries to anyone prior to open-sourcing the software?
    – Gili
    Commented May 18, 2020 at 4:48
  • @Gill: Again, hypothetical. The open-source license may have required you to provide source on demand. But until you distribute anything, open source allows unrestricted internal use.
    – MSalters
    Commented May 18, 2020 at 6:56
  • @MSalters So if I understand you correctly, you are saying that the act of distributing the source-code to our software, where older versions depend upon the open-source libraries but the latest version does not, does not trigger their licensing terms. Is that correct? Again, our scenario is: we do not distribute our software while it depends on the open-source libraries, then remove the open-source libraries, then distribute the source-code of our software where historical revisions show a dependency of open-source libraries but the latest version does not.
    – Gili
    Commented May 19, 2020 at 15:27
  • No, you didn't understand that correctly. Distribution of older versions of the source code (independent of the form of distribution) is disallowed, as there is no legal basis for that. The technical detail that the distribution happens in the form of a source code repository with history is legally irrelevant.
    – MSalters
    Commented May 21, 2020 at 10:49

1 Answer 1


After clarification:

Source code that forms a derived work from Open Source code may be created internally in a company. This is legal because Open Source conditions trigger only on distribution. However, if this source code would be distributed outside the company, it must happen on the relevant Open Source conditions. This usually also applies to derivative works, such as binary software compiled from such source and source code repositories containing that source.

It is generally recognized that such Open Source origins can be removed, which removes the resulting obligations as well. Hence, a source code repository that is truncated at the removal of said Open Source code can now be distributed without the Open Source terms applying.

The exact terms of the Open Source license are entirely irrelevant to this answer, as long as it's a true Open Source license. This is the case because in the scenario described there never was a need to accept these license terms. Hence, no contract between you and the original authors exists, and they cannot sue you for breaching it. Any suit would have to be based purely on copyright law, not license terms.

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