mir-json does not work with cargo workspaces

[TomMD]

$ cargo crux-test
thread 'main' panicked at 'error building workspace: failed to parse manifest at `/..../crucible/crux-mir/example/ffs/Cargo.toml`', src/bin/cargo_test_common.rs:86:29
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

From:

diff --git a/crux-mir/example/ffs/Cargo.toml b/crux-mir/example/ffs/Cargo.toml
index dee0e1310..a7dece731 100644
--- a/crux-mir/example/ffs/Cargo.toml
+++ b/crux-mir/example/ffs/Cargo.toml
@@ -7,6 +7,7 @@ edition = "2018"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

 [dependencies]
+byteorder = { workspace = true }

 [lib]
 path = "lib.rs"

And a new file at example/Cargo.toml of:

[workspace]
members = [ "ffs" ]

[workspace.dependencies]
byteorder = "1.4.3"

[RyanGlScott]

Curiously, this is the part of mir-json that is panicking:

    let ws = args.workspace(&config)
        .unwrap_or_else(|e| panic!("error building workspace: {}", e));

I'd need to look more closely at what workspace() is doing to tell why it's misbehaving. (Sadly, this function lacks any doc comments.)

[RyanGlScott]

I'll go ahead and transfer this issue over to the mir-json repo, as I'm fairly confident the issue lies in mir-json rather than in Crux.

I tried reading the source code for workspace() a bit, but I wasn't able to get much insight into what is going on. I'll likely need to build cargo from source (+ some additional debug printing) to figure out why workspace() is returning Err here.