When HashiCorp dumped its open-source Mozilla license for the Business Source License (BSL 1.1) for its flagship program, infrastructure as code (IaC) tool Terraform, many Terraform developers and partners were ticked off. As open source developers are wont to do in such situations, they created a Terraform fork, called OpenTofu.

So far, that’s business as usual when a company shifts a project away from open source. Things heated up, though, when the Linux Foundation announced it would support the new fork. Now, the conflict between HashiCorp and OpenTofu is starting to boil, as HashiCorp accused OpenTofu of “not respecting the terms of its BSL license governing its Terraform codebase.”

Them’s fighting words!

OpenTofu replied, “OpenTofu vehemently disagrees with any suggestion that it misappropriated, mis-sourced, or otherwise misused HashiCorp’s BSL code.” The organization added, “HashiCorp may be conflating code that it had previously been open-sourced under the MPL and more recently developed code it published under the BSL.” And, OpenTofu says, it will “issue a written response providing a more detailed explanation of its position.”

So, what is this code in question? Neither Hashicorp nor Terraform is saying, quite yet. However, it appears to be a “removed block” automation process that enables Terraform to manage resource deletion.

Matt Asay, MongoDB‘s VP of Developer Relations, revealed this accusation. He accused OpenTofu of lifting the “removed block” code, which was released under the BSL a few months after the OpenTofu fork was created. “The tell? OpenTofu took this BUSL-licensed HashiCorp code, removed the headers, and tried to instead relicense it under the Mozilla Public License (MPL 2.0),” Asay wrote.

Oh, it’s on now.

Even before news of the legally threatening message emerged, prominent open source leaders attacked Asay’s claim. Bryan Cantrill, the hyper-cloud Oxide Computer co-founder and CTO, claimed, “This is an extraordinarily serious accusation – and the cited files frankly don’t substantiate it.”

Cantrill is far from alone in thinking that there is insufficient evidence to justify the accusation that OpenTofu has stolen any code. Until we have harder evidence, the issue will remain a case of “He said, she said.”

Chris Aniszczyk, the CTO of the Cloud Native Computing Foundation (CNCF), a Linux Foundation-related organization, doesn’t think it’s a good look for HashiCorp. He said it’s “embarrassing to see a company light all of its hard-earned developer reputation on fire, on top of attacking open source.”

Dan Lorenc, CEO and co-founder of Chainguard, a software supply chain security company, warns this could be the start of something big and ugly in software development circles. “I don’t have any philosophical or ethical issues with source-available licenses, but their proponents are going to have to address these cease-and-desist threats,” he wrote. “Developers working in OSS (OSI/FSF approved licenses) are going to be prevented from engaging with or even looking at source-available projects completely to prevent the risk of lawsuits. It’s just too risky to pretend otherwise.”

Lorenc adds, “There’s no gradual transition here, it’s going to be a hard fork in communities if these lawsuit threats keep continuing. And I know which community I’d bet on sticking around.”

I lived through the SCO-Linux copyright wars. I think I know who will win, too.