Segfault when reading from serverside tcp connection

A Zig developer reports a segmentation fault at address 0x79 while reading from an accepted TCP connection using Zig 0.17.0-dev.1786+75044cb04, with the crash traced through std.Io.zig:554 in io.vtable.operate during a call to Reader.fillMore. The developer's first Zig project, a sensor-measurement collection server binding to ::1 port 1312, segfaults immediately after netcat connects and the code calls ri.fillMore(). The stack trace points to std/Io/net.zig:1275 in read and std/Io/Reader.zig:1138 in fillMore, and the developer is asking for help diagnosing the failure.

heyo everyone, this one is coming to zig in hopes of having fun with computers and other beings, learning cool programming stuff, and being not less bothered by llms and ai bs. This one did some ziglings exercises to get into the language and has now started on its first zig project, a collection server for sensor measurements. The sensors will most likely talk with the server using json inside http inside mutual tls. For now this one’s goal is to bind to a socket, to accept connections and read from them. This one is running into issues trying to read from a connection: js const std = @import "std" ; const Io = std.Io; const dprint = std.debug.print; pub fn main init: std.process.Init void { // In order to do I/O operations need an Io instance. const io = init.io; const address = try std.Io.net.IpAddress.parse "::1", 1312 ; dprint "addr: {}\n", .{address} ; var listener = try address.listen io, .{ .reuse address = true, } ; defer listener.deinit io ; var buffer: 1024 u8 = undefined; while true { const stream = try listener.accept io ; dprint "accepted connection from: {}\n", .{stream.socket.address} ; const reader = stream.reader io, &buffer ; var ri = reader.interface; if ri.fillMore { dprint "possibly filled the buffer", .{} ; } else |err| { dprint "failed to fill the buffer because: {any}", .{err} ; } // if ri.takeDelimiterInclusive '\n' |line| { // dprint "line: {s}", .{line} ; // } else |err| { // dprint "error: {}", .{err} ; // } try stream.shutdown io, .both ; } } When run this code produces this output and segfaults when getting a connection from netcat : addr: .{ .ip6 = .{ .port = 1312, .bytes = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 }, .flow = 0, .interface = .{ .index = 0 } } } accepted connection from: .{ .ip6 = .{ .port = 40616, .bytes = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 }, .flow = 0, .interface = .{ .index = 0 } } } Segmentation fault at address 0x79 /home/digital/zig-x86 64-linux-0.17.0-dev.1786+75044cb04/lib/std/Io.zig:554:29: 0x103e393 in operate std.zig return io.vtable.operate io.userdata, operation ; ^ /home/digital/zig-x86 64-linux-0.17.0-dev.1786+75044cb04/lib/std/Io/net.zig:1275:31: 0x11f3118 in read std.zig return try io.operate .{ .net read = .{ ^ /home/digital/zig-x86 64-linux-0.17.0-dev.1786+75044cb04/lib/std/Io/net.zig:1329:36: 0x11f2b85 in readVec std.zig const n = r.stream.read io, dest catch |err| { ^ /home/digital/zig-x86 64-linux-0.17.0-dev.1786+75044cb04/lib/std/Io/Reader.zig:1138:29: 0x108422b in fillMore std.zig = try r.vtable.readVec r, &bufs ; ^ /home/digital/projects/comfy-aggregator/src/main.zig:26:24: 0x11e532f in main main.zig if ri.fillMore { ^ /home/digital/zig-x86 64-linux-0.17.0-dev.1786+75044cb04/lib/std/start.zig:797:30: 0x11e5f98 in callMain std.zig return wrapMain root.main .{ ^ /home/digital/zig-x86 64-linux-0.17.0-dev.1786+75044cb04/lib/std/start.zig:218:5: 0x11e4ca1 in start std.zig asm volatile switch native arch { ^ fish: Job 1, './zig-out/bin/comfy aggregator …' terminated by signal SIGABRT Abort This one is using zig 0.17.0-dev.1786+75044cb04 because that’s what ziglings asked for . Please help this one by teaching it how to find a solution for its problem or explain why this is failing.