Multiple back to back Bun segfault crashes #33821

Description

All was going fine today, until at some point my agent attempted to make an edit to a file, then I had my first segfault crash, then I asked the agent to actually explain what it could have done to cause this and here was its thinking process:

## Assistant (Build · Qwen3.6 · 7.9s)

_Thinking:_

The user is upset. Two things happened:
1. I sent an empty `edit` tool call (the last one had no `oldString` parameter - that was a mistake in my call)
2. That caused something to crash in bun/opencode

The last edit call was `{"filePath": "C:\\Users\\Administrator\\Documents\\chatbot-widget\\src\\chat.css", "oldString": ""}` - it had no `newString` and no content to match. That was clearly a mistake - I was going to make one more edit but forgot to include the content.

Then it goes on thinking and checking what tasks remain for completion, then:

Let me make the remaining edits.

**Tool: edit**

**Input:**
json
{
  "filePath": "C:\\Users\\Administrator\\Documents\\chatbot-widget\\src\\chat.css",
  "oldString": ".sh24x-refresh {\n  & svg > path {\n    transition: stroke 250ms ease;\n    stroke: var(--h1-t);\n  }\n}",
  "newString": ".sh24x-refresh {\n  & svg > path {\n    transition: stroke 250ms ease;\n    stroke: var(--neutral-800);\n  }\n}"
}

**Tool: edit**

**Input:**
json
{}

---

## User

What about this time? You probably broke it again

This is the last log from the chat before a second segfault crash happens. You can see that there is no other detail in the chat copy itself as the following content is my message I sent after restarting opencode and going back to the same session. This crash happens again third time.

Then, I create a new session, this time specifically asking the agent to check if this repo has any existing bug reports for this kind of thing, and it crashed in this session too! This time no edit tool calls, only webfetch and bash (for gh issue *).

Then, I restarted opencode and started a new session, this time asking the agent to gather necessary system info to so I can prepare the bug report with relevant details. That's when I had my fifth crash.

Until this point, all of the crashes happened during an active session where agent would be doing something like thinking/responding or calling tools, etc.

However, my sixth and latest segfault crash literally happened while I was doing nothing active. I was actually going through the three aforementioned sessions trying to gather info for this report, and as soon as I typed / in chat so I could write /sessions to switch to another

System Information:

• OS: Microsoft Windows 11 Pro, Version 10.0.26100 Build 26100
• System Model: Dell Inc. OptiPlex 9020
• Processor: Intel64 Family 6 Model 60 Stepping 3 GenuineIntel ~3401 MHz (1 processor)
• RAM: 32,673 MB total (18,472 MB available)
• BIOS Version: Dell Inc. A15, 08.11.2015
• System Locale: de;German (Germany)
• Input Locale: tr;Turkish
• Time Zone: (UTC+01:00) Amsterdam, Berlin, Bern, Rome, Stockholm, Vienna

Network:

• Adapter: Intel(R) Ethernet Connection I217-LM
• IP Address: 10.10.12.152 (DHCP enabled, server: 10.10.12.1)

Virtualization:

• Virtualization-Based Security: Running
• Hyper-V Requirements: Hypervisor detected; Hyper-V required features not displayed

Installed Hotfixes: KB5087054, KB5050575, KB5054273, KB5065847, KB5068861, KB5083532

Plugins

None that I am aware of

OpenCode version

1.17.10

Steps to reproduce

1. open OpenCode on Windows
2. perhaps pick a local hosted Qwen3.6 model if that's relevant
3. try to do any standard coding or debug session

Screenshot and/or share link

Operating System

Microsoft Windows 11 Pro, Version 10.0.26100 Build 26100

Terminal

Windows Terminal with Nushell