Build segfaults in `--system` mode if a dependency has a path dependency

[dermetfan]

Zig Version

• 0.13.0
• 0.14.0-dev.1798+148b5b4c7

Steps to Reproduce and Observed Behavior

zig build segfaults in --system mode when build.zig.zon has a dependency that

• is not a path dependency and
• has another dependency that is a path dependency.

Visually:

A --(http)--> B --(path)--> C

I prepared a little repository so you can reproduce easily by following the steps in its README: https://github.com/dermetfan/zig-build-segfault

cd a
zig build --fetch
zig build --system ~/.cache/zig/p

Expected Behavior

The build should succeed normally, as is the case without --system.

[BratishkaErik]

Output on 0.14.0-dev.1820+ea527f7a8 -Doptimize=Debug

thread 11074 panic: attempt to use null value
/home/bratishkaerik/github.com/zig/src/main.zig:5268:76: 0x1a1e1bf in cmdBuild (zig)
                            const dep_mod = job_queue.table.get(dep_digest).?.module orelse continue;
                                                                           ^
/home/bratishkaerik/github.com/zig/src/main.zig:279:24: 0x185bf74 in mainArgs (zig)
        return cmdBuild(gpa, arena, cmd_args);
                       ^
/home/bratishkaerik/github.com/zig/src/main.zig:198:20: 0x1858a85 in main (zig)
    return mainArgs(gpa, arena, args);
                   ^
/home/bratishkaerik/github.com/zig/lib/std/start.zig:621:37: 0x185858e in main (zig)
            const result = root.main() catch |err| {
                                    ^
???:?:?: 0x7f94ec05d379 in ??? (libc.so.6)
Unwind information for `libc.so.6:0x7f94ec05d379` was not available, trace may be incomplete

???:?:?: 0x7f94ec05d43a in ??? (libc.so.6)
???:?:?: 0x18581d4 in ??? (???)
[1]    11074 IOT instruction  ~/github.com/zig/build/stage3/bin/zig build --system ~/.cache/zig/p/