cmd/cue: import on a valid JSONSchema file fails

[jpluscplusm]

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

$ cue version
cue version v0.6.0

go version go1.20.6
      -buildmode exe
       -compiler gc
       -trimpath true
     CGO_ENABLED 0
          GOARCH amd64
            GOOS linux
         GOAMD64 v1

Does this issue reproduce with the latest stable release?

Yes, 0.6.0.

What did you do?

I attempted to import the (current) tip-of-main (JSON)schema for GitLab CI/CD pipelines:

exec wget -q https://gitlab.com/gitlab-org/gitlab/-/raw/2e31bcdbead44ef80052f6c3db5dd98f465ba241/app/assets/javascripts/editor/schema/ci.json
exec cue import jsonschema: ci.json

What did you expect to see?

I expected cue to succeed, emitting a CUE version of the schema.

What did you see instead?

> exec wget -q https://gitlab.com/gitlab-org/gitlab/-/raw/2e31bcdbead44ef80052f6c3db5dd98f465ba241/app/assets/javascripts/editor/schema/ci.json
> exec cue import jsonschema: ci.json
[stderr]
constraint not allowed because type string is excluded:
    ./ci.json:126:17
constraint not allowed because type string is excluded:
    ./ci.json:546:11
constraint not allowed because type string is excluded:
    ./ci.json:852:13
constraint not allowed because type string is excluded:
    ./ci.json:904:13
schema expects mapping node, found bool:
    ./ci.json:959:9
schema expects mapping node, found bool:
    ./ci.json:989:9
schema expects mapping node, found bool:
    ./ci.json:1002:9
constraint not allowed because type string is excluded:
    ./ci.json:1550:15
constraint not allowed because type string is excluded:
    ./ci.json:2130:7
constraint not allowed because type string is excluded:
    ./ci.json:2140:13
[exit status 1]
FAIL: /tmp/testscript2818960354/gitlab-schema.txtar/script.txtar:2: unexpected command failure
error running gitlab-schema.txtar in /tmp/testscript2818960354/gitlab-schema.txtar

Using https://www.jsonschemavalidator.net/, I was able to successfully validate the GitLab file against the appropriate JSONSchema meta-schema, suggesting that cue's objections aren't fundamental to the file's contents.

An earlier version of the same GitLab schema was flagged in an seemingly unrelated issue, here: #1487

[justenstall]

Ran into the same blocker trying to import the JSON Schema for Renovate configuration.

$ curl https://docs.renovatebot.com/renovate-schema.json > renovate-schema.json
$ cue import jsonschema renovate-schema.json --verbose --trace -E
constraint not allowed because type array is excluded:
    ./renovate-schema.json:648:7
constraint not allowed because type array is excluded:
    ./renovate-schema.json:2497:7
$ cue version
cue version v0.7.0

go version go1.21.5
      -buildmode exe
       -compiler gc
       -trimpath true
  DefaultGODEBUG panicnil=1
     CGO_ENABLED 1
          GOARCH arm64
            GOOS darwin

For some context, here are the items at lines 648 and 2497:

Line 648 is properties.customDatasources.items:

{
  "properties": {
    "customDatasources": {
      "items": {
        "allOf": [
          {
            "type": "object",
            "properties": {
              "description": {
                "type": "string",
                "description": "A custom description for this configuration object"
              },
              "defaultRegistryUrlTemplate": {
                "description": "Template for generating a `defaultRegistryUrl` for custom datasource.",
                "type": "string",
                "default": ""
              },
              "format": {
                "description": "Format of the custom datasource.",
                "type": "string",
                "enum": [
                  "json",
                  "plain"
                ],
                "default": "json"
              },
              "transformTemplates": {
                "description": "List of jsonata transformation rules.",
                "type": "array",
                "items": {
                  "type": "string"
                },
                "default": []
              }
            }
          }
        ]
      }
    }
  }
}   

Line 2497 is properties.postUpgradeTasks.items:

{
  "properties": {
    "postUpgradeTasks": {
      "items": {
        "allOf": [
          {
            "type": "object",
            "properties": {
              "description": {
                "type": "string",
                "description": "A custom description for this configuration object"
              },
              "commands": {
                "description": "A list of post-upgrade commands that are executed before a commit is made by Renovate.",
                "type": "array",
                "items": {
                  "type": "string"
                },
                "default": []
              },
              "executionMode": {
                "description": "Controls when the post upgrade tasks run: on every update, or once per upgrade branch.",
                "type": "string",
                "enum": [
                  "update",
                  "branch"
                ],
                "default": "update"
              },
              "fileFilters": {
                "description": "Files that match the glob pattern will be committed after running a post-upgrade task.",
                "type": "array",
                "items": {
                  "type": "string"
                },
                "default": [
                  "**/*"
                ]
              }
            }
          }
        ]
     }
  }
}

[kharf]

Ran into the same blocker trying to import the JSON Schema for Renovate configuration.

$ curl https://docs.renovatebot.com/renovate-schema.json > renovate-schema.json
$ cue import jsonschema renovate-schema.json --verbose --trace -E
constraint not allowed because type array is excluded:
    ./renovate-schema.json:648:7
constraint not allowed because type array is excluded:
    ./renovate-schema.json:2497:7
$ cue version
cue version v0.7.0

go version go1.21.5
      -buildmode exe
       -compiler gc
       -trimpath true
  DefaultGODEBUG panicnil=1
     CGO_ENABLED 1
          GOARCH arm64
            GOOS darwin

For some context, here are the items at lines 648 and 2497:

Line 648 is properties.customDatasources.items:

{
  "properties": {
    "customDatasources": {
      "items": {
        "allOf": [
          {
            "type": "object",
            "properties": {
              "description": {
                "type": "string",
                "description": "A custom description for this configuration object"
              },
              "defaultRegistryUrlTemplate": {
                "description": "Template for generating a `defaultRegistryUrl` for custom datasource.",
                "type": "string",
                "default": ""
              },
              "format": {
                "description": "Format of the custom datasource.",
                "type": "string",
                "enum": [
                  "json",
                  "plain"
                ],
                "default": "json"
              },
              "transformTemplates": {
                "description": "List of jsonata transformation rules.",
                "type": "array",
                "items": {
                  "type": "string"
                },
                "default": []
              }
            }
          }
        ]
      }
    }
  }
}   

Line 2497 is properties.postUpgradeTasks.items:

{
  "properties": {
    "postUpgradeTasks": {
      "items": {
        "allOf": [
          {
            "type": "object",
            "properties": {
              "description": {
                "type": "string",
                "description": "A custom description for this configuration object"
              },
              "commands": {
                "description": "A list of post-upgrade commands that are executed before a commit is made by Renovate.",
                "type": "array",
                "items": {
                  "type": "string"
                },
                "default": []
              },
              "executionMode": {
                "description": "Controls when the post upgrade tasks run: on every update, or once per upgrade branch.",
                "type": "string",
                "enum": [
                  "update",
                  "branch"
                ],
                "default": "update"
              },
              "fileFilters": {
                "description": "Files that match the glob pattern will be committed after running a post-upgrade task.",
                "type": "array",
                "items": {
                  "type": "string"
                },
                "default": [
                  "**/*"
                ]
              }
            }
          }
        ]
     }
  }
}

It is due to "customDatasources" and "postUpgradeTasks" being declared as objects, but they are both arrays. In my opinion the errors are correct in this case.

[jpluscplusm]

Closing, as either the fix outlined in #1939 (https://gitlab.com/gitlab-org/gitlab/-/merge_requests/148555), or some preceding change to GitLab's schema, now permits GitLab's tip-of-master JSON Schema (https://gitlab.com/gitlab-org/gitlab/-/raw/master/app/assets/javascripts/editor/schema/ci.json) to be successfully imported by cue v0.8.0.