cmd/cue: incorrect cyclic task dependency error

[networkhermit]

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

$ cue version
cue version 0.8.1

go version go1.22.2
      -buildmode pie
       -compiler gc
       -trimpath true
  DefaultGODEBUG httplaxcontentlength=1,httpmuxgo121=1,tls10server=1,tlsrsakex=1,tlsunsafeekm=1
     CGO_ENABLED 1
          GOARCH amd64
            GOOS linux
         GOAMD64 v1

Does this issue reproduce with the latest stable release?

Yes.

What did you do?

1. copy the following code to test_tool.cue

package main

import (
	"tool/exec"
)

command: test: [string]: [string]: exec.Run

command: test: {
	group1: x={
		let tasks = [
			{cmd: "echo a"},
			{cmd: "echo b"},
			{cmd: "echo c"},
		]
		for i, v in tasks {
			"s\(i+1)": v & {
				if i != 0 {
					$after: x["s\(i)"]
				}
			}
		}
	}
	group2: x={
		let tasks = [
			{cmd: "echo x"},
			{cmd: "echo y"},
			{cmd: "echo z"}, // reduce the list elements to 2, e.g. comment this line, invalidate the cyclic error
		]
		for i, v in tasks {
			"s\(i+1)": v & {
				if i == 0 {
					$after: [for v in group1 {v}]
				}
				if i != 0 {
					$after: x["s\(i)"] // or change this reference to [x["s\(i)"]]
				}
			}
		}
	}
}

2. run cue cmd test

P.S.

The comments in the above code point two modifications which won't trigger the cyclic error.

What did you expect to see?

a
b
c
x
y
z

What did you see instead?

cyclic task dependency:
        task command.test.group2.s1 refers to
        task command.test.group2.s2 refers to
        task command.test.group2.s1:
    ./test_tool.cue:7:36

[networkhermit]

Catched another incorrect snippet. Unfortunately this time I'm out of luck.

❯ cue cmd test
cyclic task dependency:
        task command.test.s2 refers to
        task command.test.s3 refers to
        task command.test.s2:
    ./test_tool.cue:7:26

package main

import (
	"tool/exec"
)

command: test: [string]: exec.Run

command: test: X={
	let tasks = [
		{cmd: "echo a"},
		{cmd: "echo 1"},
		{cmd: "echo 2", $dep: [0]},
		{cmd: "echo 3", $dep: [0]},
		{cmd: "echo 4", $dep: [0]},
		{cmd: "echo 5", $dep: [0]},
		{cmd: "echo z", $dep: [1, 2, 3, 4, 5]},
	]
	for i, v in tasks {
		"s\(i+1)": v & {
			if i != 0 {
				let p = (v.$dep & [...int]) != _|_
				if p {
					$after: [for i in v.$dep {X["s\(i+1)"]}]
				}
				if !p {
					$after: [X["s\(i)"]]
				}
			}
		}
	}
}

cue eval output seems ok.

❯ cue eval - < test_tool.cue
command: {
    test: {
        s1: {
            $id: "tool/exec.Run"
            cmd: "echo a"
            env: {} | []
            stdout:      null
            stderr:      null
            stdin:       null
            success:     bool
            mustSucceed: true
        }
        s2: {
            $id: "tool/exec.Run"
            cmd: "echo 1"
            env: {} | []
            stdout:  null
            stderr:  null
            stdin:   null
            success: bool
            $after: [{
                $id: "tool/exec.Run"
                cmd: "echo a"
                env: {} | []
                stdout:      null
                stderr:      null
                stdin:       null
                success:     bool
                mustSucceed: true
            }]
            mustSucceed: true
        }
        s3: {
            $id: "tool/exec.Run"
            cmd: "echo 2"
            env: {} | []
            stdout:  null
            stderr:  null
            stdin:   null
            success: bool
            $after: [{
                $id: "tool/exec.Run"
                cmd: "echo a"
                env: {} | []
                stdout:      null
                stderr:      null
                stdin:       null
                success:     bool
                mustSucceed: true
            }]
            $dep: [0]
            mustSucceed: true
        }
        s4: {
            $id: "tool/exec.Run"
            cmd: "echo 3"
            env: {} | []
            stdout:  null
            stderr:  null
            stdin:   null
            success: bool
            $after: [{
                $id: "tool/exec.Run"
                cmd: "echo a"
                env: {} | []
                stdout:      null
                stderr:      null
                stdin:       null
                success:     bool
                mustSucceed: true
            }]
            $dep: [0]
            mustSucceed: true
        }
        s5: {
            $id: "tool/exec.Run"
            cmd: "echo 4"
            env: {} | []
            stdout:  null
            stderr:  null
            stdin:   null
            success: bool
            $after: [{
                $id: "tool/exec.Run"
                cmd: "echo a"
                env: {} | []
                stdout:      null
                stderr:      null
                stdin:       null
                success:     bool
                mustSucceed: true
            }]
            $dep: [0]
            mustSucceed: true
        }
        s6: {
            $id: "tool/exec.Run"
            cmd: "echo 5"
            env: {} | []
            stdout:  null
            stderr:  null
            stdin:   null
            success: bool
            $after: [{
                $id: "tool/exec.Run"
                cmd: "echo a"
                env: {} | []
                stdout:      null
                stderr:      null
                stdin:       null
                success:     bool
                mustSucceed: true
            }]
            $dep: [0]
            mustSucceed: true
        }
        s7: {
            $id: "tool/exec.Run"
            cmd: "echo z"
            env: {} | []
            stdout:  null
            stderr:  null
            stdin:   null
            success: bool
            $after: [{
                $id: "tool/exec.Run"
                cmd: "echo 1"
                env: {} | []
                stdout:  null
                stderr:  null
                stdin:   null
                success: bool
                $after: [{
                    $id: "tool/exec.Run"
                    cmd: "echo a"
                    env: {} | []
                    stdout:      null
                    stderr:      null
                    stdin:       null
                    success:     bool
                    mustSucceed: true
                }]
                mustSucceed: true
            }, {
                $id: "tool/exec.Run"
                cmd: "echo 2"
                env: {} | []
                stdout:  null
                stderr:  null
                stdin:   null
                success: bool
                $after: [{
                    $id: "tool/exec.Run"
                    cmd: "echo a"
                    env: {} | []
                    stdout:      null
                    stderr:      null
                    stdin:       null
                    success:     bool
                    mustSucceed: true
                }]
                $dep: [0]
                mustSucceed: true
            }, {
                $id: "tool/exec.Run"
                cmd: "echo 3"
                env: {} | []
                stdout:  null
                stderr:  null
                stdin:   null
                success: bool
                $after: [{
                    $id: "tool/exec.Run"
                    cmd: "echo a"
                    env: {} | []
                    stdout:      null
                    stderr:      null
                    stdin:       null
                    success:     bool
                    mustSucceed: true
                }]
                $dep: [0]
                mustSucceed: true
            }, {
                $id: "tool/exec.Run"
                cmd: "echo 4"
                env: {} | []
                stdout:  null
                stderr:  null
                stdin:   null
                success: bool
                $after: [{
                    $id: "tool/exec.Run"
                    cmd: "echo a"
                    env: {} | []
                    stdout:      null
                    stderr:      null
                    stdin:       null
                    success:     bool
                    mustSucceed: true
                }]
                $dep: [0]
                mustSucceed: true
            }, {
                $id: "tool/exec.Run"
                cmd: "echo 5"
                env: {} | []
                stdout:  null
                stderr:  null
                stdin:   null
                success: bool
                $after: [{
                    $id: "tool/exec.Run"
                    cmd: "echo a"
                    env: {} | []
                    stdout:      null
                    stderr:      null
                    stdin:       null
                    success:     bool
                    mustSucceed: true
                }]
                $dep: [0]
                mustSucceed: true
            }]
            $dep: [1, 2, 3, 4, 5]
            mustSucceed: true
        }
    }
}