Reading into empty buffer will panic std.compress.flate.decompressor.

[pavelverigo]

Zig Version

0.13.0-dev.75+5c9eb4081

Steps to Reproduce and Observed Behavior

This code will produce panic:

const std = @import("std");

pub fn main() !void {
    const bytes = &[_]u8{
        0b0000_0001, 0b0000_1100, 0x00, 0b1111_0011, 0xff, // deflate fixed buffer header len, nlen
        'H', 'e', 'l', 'l', 'o', ' ', 'w', 'o', 'r', 'l', 'd', 0x0a, // non compressed data
    };
    var fbs = std.io.fixedBufferStream(bytes);
    var gz = std.compress.flate.decompressor(fbs.reader());
    var tmp: [0]u8 = undefined;
    _ = try gz.read(&tmp);
}

Panic:

thread 22216 panic: index out of bounds: index 12, len 0
zig\lib\std\compress\flate\inflate.zig:352:27: 0xdf1287 in read (check.exe.obj)
            @memcpy(buffer[0..out.len], out);
                          ^
main.zig:11:20: 0xdf109f in main (check.exe.obj)
    _ = try gz.read(&tmp);

Expected Behavior

Not panic.