cmd/cue: attempt to import package from main module fails

[myitcv]

What version of CUE are you using (cue version)?

$ cue version
cue version v0.0.0-20241230133743-46fc54aa9caf

go version go1.23.2
      -buildmode exe
       -compiler gc
  DefaultGODEBUG asynctimerchan=1,gotypesalias=0,httpservecontentkeepheaders=1,tls3des=1,tlskyber=0,x509keypairleaf=0,x509negativeserial=1
     CGO_ENABLED 1
          GOARCH arm64
            GOOS linux
         GOARM64 v8.0
             vcs git
    vcs.revision 46fc54aa9caf95393dcd3fe0ac066c8112da986d
        vcs.time 2024-12-30T13:37:43Z
    vcs.modified false
cue.lang.version v0.12.0

Does this issue reproduce with the latest release?

Yes and tip.

What did you do?

# export :a in root
exec cue export .:a
cmp stdout $WORK/stdout.a.golden

# export :b in root
exec cue export .:b
cmp stdout $WORK/stdout.b.golden

# cd test
cd test

# export :c in test
exec cue export .:c
cmp stdout $WORK/stdout.c.golden

# export :b in test
exec cue export .:b
cmp stdout $WORK/stdout.b.golden

# export :a in test
exec cue export .:a
cmp stdout $WORK/stdout.a.golden

-- a.cue --
package a

import B "broken.io/x:b"

a:  "a"
bb: "\(B.b)"
-- b.cue --
package b

b: "b"
-- cue.mod/module.cue --
module: "broken.io/x"
language: {
	version: "v0.12.0"
}
-- test/c.cue --
package c

c: "c"
-- stdout.a.golden --
{
    "a": "a",
    "bb": "b"
}
-- stdout.b.golden --
{
    "b": "b"
}
-- stdout.c.golden --
{
    "c": "c"
}

What did you expect to see?

Passing test.

What did you see instead?

# export :a in root (0.014s)
# export :b in root (0.011s)
# cd test (0.000s)
# export :c in test (0.010s)
# export :b in test (0.010s)
# export :a in test (0.011s)
> exec cue export .:a
[stderr]
broken.io/x/test@v0: import failed: no dependency found for package "broken.io/x":
    ../a.cue:3:8
[exit status 1]
FAIL: /tmp/testscript4243465204/repro.txtar/script.txtar:21: unexpected command failure