The drama began in April 2025 when GitHub user AlekseiNikiforovIBM started a thread titled “safe_sleep.sh rarely hangs indefinitely”. GitHub addressed the issue in August, but did not disclose it in the thread, which remained open as of Monday.
The code uses 100 percent CPU all the time, and will always run
That time seems remarkable. Last week, Andrew Kelly, president and lead developer of the Zig Software Foundation, announced that the Zig project is moving to Codeberg, a non-profit Git hosting service, because GitHub no longer demonstrates a commitment to engineering excellence.
The evidence they presented for that assessment was “safe_sleep.sh rarely hangs indefinitely”.
“Most importantly, there are inexcusable bugs in the action while it is being completely ignored,” Kelly wrote. “After the GitHub CEO said ’embrace AI or get out’, it seems the bastards at Microsoft took the hint, because GitHub Actions started ‘vibe-scheduling’ – randomly picking jobs to run. Combined with other bugs and the inability to manually intervene, this backed up our CI system so much that even master branch commits weren’t checked out.”
old and dark
Kelly’s complaint seems justified, as the bug discussed in the thread appeared after a code change in February 2022 that users flagged in a prior bug report.
The code change replaced the instances of the POSIX “sleep” command with a “safe_sleep” script that failed to work as advertised. This was supposed to allow the GitHub Actions Runner – the application that runs a task from a GitHub Actions workflow – to safely stop execution.
“The bug in this ‘safe sleep’ script is clear from looking at it: if the process is not set to a one-second interval in which the loop will return (due to having the correct value of $SECONDS), then it simply loops forever,” Zig core developer Matthew Lugg wrote in a comment attached to the April bug thread.
“This can easily happen on a CI machine under extreme load. When this happens, it’s very bad: it completely breaks a runner until manual intervention. On Zig’s CI runner machines, we saw many of these processes running for hundreds of hours, silently shutting down two runner services for weeks.”
The fix from a different issue opened in February 2024 was merged on August 20, 2025. Bug reports related to April 2025 remained open until Monday, December 1, 2025. An isolated CPU usage bug remains unresolved.
Jeremy Howard, co-founder of Answer.AI and Fast.AI, said in a series of social media posts that users’ claims about the poor state of repair of GitHub Actions appear to be justified.
“The bug,” he wrote, “was implemented in a way that, at first glance to almost anyone, uses 100 percent of the CPU all the time, and it will run forever unless the task occurs to check the time during the correct number of seconds.”
I cannot understand how such an extraordinary collection of face-to-face events could be created
He said a platform-independent solution to the CPU issue proposed last February languished without review for a year and was shut down by a GitHub bot in March 2025 before being revived and merged.
Howard concluded, “While one might say that this is just one isolated incident, I cannot see how such an extraordinary collection of one-off face-to-face incidents could be created in any reasonably functioning organization.”
GitHub did not immediately respond to a request for comment.
While Kelly has apologized for the inflammatory nature of his post, Zig is not the only software project to publicly break away from GitHub.
Over the weekend, Rodrigo Arias Mello, creator of the Dilo browser project, said he planned to move away from GitHub due to concerns about its excessive reliance on JavaScript, GitHub’s ability to perform a denial of service, declining usability, inadequate moderation tools, and “focusing more on LLM and generative AI, which are destroying the open web (or what’s left of it), among other problems.”
For its part, Codeberg has doubled its affiliate membership since January, growing from more than 600 members to more than 1,200 as of last week.
GitHub has not disclosed how many of its users currently pay for its services. Microsoft CEO Satya Nadella said on the company’s Q2 2024 earnings call that the code hosting business had “more than 1.3 million paid GitHub Copilot customers, up 30 percent quarter-over-quarter.”
In Q4 2024, when GitHub reported an annual revenue run rate of $2 billion, GitHub Copilot subscriptions accounted for nearly 40 percent of the company’s annual revenue growth.
Nadella offered a different figure during Microsoft’s Q3 2025 earnings call: “We now have over 15 million GitHub Copilot users, up more than 4X year-over-year.” It’s unclear how many GitHub users paid for Copilot, or for the runner scripts that burned CPU cycles when they should have been asleep.
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