Server crashes while after build-on-save zls tries to processMessageReportError #2539
Description
Zig Version
0.16.0-dev.1657+985a3565c
ZLS Version
0.16.0-dev.77+d84c451f
Client / Code Editor / Extensions
Visual Studio Code (1.107.0)
Steps to Reproduce and Observed Behavior
Behavior (after saving):
- No changes in editor
- After 5 saves VSCode saying "Server will not be restarted"
Steps to reproduce:
- Download ZLS official extension in VSCode
- Open any project build with Zig
- Try to save file
- In
OUTPUTsection will be logs with crash
Expected Behavior
Working error highlighting
Log Output
info ( main ): Starting ZLS 0.16.0-dev.77+d84c451f @ '/home/ubuntu/.config/Code/User/globalStorage/ziglang.vscode-zig/zls/aarch64-linux-0.16.0-dev.77+d84c451f/zls'
info ( main ): Log File: /home/ubuntu/.cache/zls/zls.log (info)
info (server): Client Info: Visual Studio Code (1.107.0)
info (server): added Workspace Folder: file:///home/ubuntu/Projects/Zig/ziglings
info (server): Set config option 'enable_build_on_save' to true
info (server): Set config option 'semantic_tokens' to "partial"
info (server): Set config option 'inlay_hints_hide_redundant_param_names' to true
info (server): Set config option 'warn_style' to true
info (server): Set config option 'builtin_path' to "/home/ubuntu/.cache/zls/builtin.zig"
info (server): Set config option 'zig_lib_path' to "/home/ubuntu/.local/zig/lib"
info (server): Set config option 'zig_exe_path' to "/home/ubuntu/.local/zig/zig"
info (server): Set config option 'build_runner_path' to "/home/ubuntu/.cache/zls/build_runner/01e80f3ae08c8c7bd679a68ca70be783/build_runner.zig"
info (server): Set config option 'global_cache_path' to "/home/ubuntu/.cache/zls"
info (server): trying to start Build-On-Save for 'file:///home/ubuntu/Projects/Zig/ziglings'
warn (server): Build-On-Save cannot run in watch mode because it is not supported by Linux '5.10.0' (requires at least 6.5.0)
warn ( diag ): zig build runner exited with non-zero status: 2
stderr:
_ _ _
___(_) __ _| (_)_ __ __ _ ___
|_ | |/ _' | | | '_ \ / _' / __|
/ /| | (_| | | | | | | (_| \__ \
/___|_|\__, |_|_|_| |_|\__, |___/
|___/ |___/
"Look out! Broken programs below!"
Compiling: 022_errors2.zig
error: 1 compilation errors
exercises/022_errors2.zig:22:24: error: expected type expression, found '='
var my_number: ??? = 5;
^
Ziglings hint: Get the error union type right to allow this to compile.
Edit exercises/022_errors2.zig and run 'zig build' again.Additional info in OUTPUT section in VSCode:
2025-12-26 20:15:18.100 [error] thread 610878 panic: attempt to use null value
2025-12-26 20:15:18.261 [error] /home/runner/work/zls/zls/src/Server.zig:1848:76: 0x10b138b in processMessage (zls)
2025-12-26 20:15:18.263 [error] /home/runner/work/zls/zls/src/Server.zig:1859:30: 0x109333f in processMessageReportError (zls)
2025-12-26 20:15:18.263 [error] /home/runner/work/zls/zls/src/Server.zig:1746:45: 0x1098f77 in loop (zls)
2025-12-26 20:15:18.263 [error] /home/runner/work/_temp/fcfda699-096a-4dba-a700-8dc07c787d9e/zig-x86_64-linux-0.16.0-dev.1657+985a3565c/lib/std/start.zig:714:37: 0x1093217 in callMain (zls)
2025-12-26 20:15:18.281 [error] Server process exited with signal SIGABRT.
2025-12-26 20:15:18.287 [error] The ZLS language server server crashed 5 times in the last 3 minutes. The server will not be restarted. See the output for more information.