panic_cannot_reduce_testcase.zig

const std = @import("std");
const c = @cImport({
    @cInclude("X11/Xlib.h");
    @cInclude("time.h");
});

const X11Error = error{
    NoDisplay,
    InternalError,
    SyncFailed,
};

const X11 = struct {
    handle: ?*c.Display,

    pub fn new() X11Error!X11 {
        const handle = c.XOpenDisplay(null);
        if (handle == null) {
            return X11Error.NoDisplay;
        }

        return X11 {
            .handle = handle
        };
    }

    pub fn setName(self: X11, name: []const u8) X11Error!void {
        if (c.XStoreName(self.handle, c.XDefaultRootWindow(self.handle),
                         name[0.. :0]) == 0) {
            return X11Error.InternalError;
        }

        if (c.XSync(self.handle, c.True) == 0) {
            return X11Error.SyncFailed;
        }
    }
};

fn currentTime() []const u8 {
    var buffer: [64]u8 = undefined;
    const clock: c.time_t = c.time(null);
    const time: ?*c.tm = c.localtime(&clock);
    const size = c.strftime(&buffer, buffer.len, "%Y-%m-%d %H:%M:%S", time);
    return buffer[0..size];
}

pub fn main() anyerror!void {
    const desktop = try X11.new();

    const time = currentTime();
    try desktop.setName(time);
}

03:20 <andrewrk> another user recently figured out how to use creduce with zig
03:22 <andrewrk> keegans, this is definitely a compiler bug, but name[0.. :0] is almost certainly incorrect, because you're accessing outside the name slice
03:22 <andrewrk> if the byte after the name slice is 0 then it should be `name: [:0]const u8` rather than `name: []const u8`
03:23 <andrewrk> so you don't need name[0.. :0] at all, just name. but update the parameter type. and update currentTime to return [:0]const u8 instead of []const u8, by changing buffer[0..size] to buffer[0..size :0]
03:24 <andrewrk> give the type system all that juicy info