[BUG] TEST: Potential Bug — `fab exists` returns strings instead of booleans in `--output_format json` (upstream #107)

[ayeshurun]

📋 Copied from microsoft/fabric-cli#107 for AI triage testing.
Expected triage outcome: Potential Bug

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Bug Description

When output_format=json is configured (either via config file or --output_format json argument) the exists command returns boolean values as strings "true" or "false" instead of native JSON booleans. This forces the user to parse strings instead of using boolean values directly. Furthermore this can cause logic errors as "false" is truthy in conditional checks.

fab exists ws1.Workspace/lh1.Lakehouse --output_format json
{
    "timestamp": "2025-12-29T16:42:07.387900Z",
    "status": "Success",
    "command": "exists",
    "result": {
        "message": "true"
    }
}

fabric-cli version

1.3.1.

Python version

3.12.3

Operating System

Windows

CLI Mode

Command line mode

Authentication Method

Service principal (secret)

Steps to Reproduce

fab exists / --output_format json
{
    "timestamp": "2025-12-29T16:42:07.387900Z",
    "status": "Success",
    "command": "exists",
    "result": {
        "message": "true"
    }
}

Expected Behavior

fab exists / --output_format json
{
    "timestamp": "2025-12-29T16:42:07.387900Z",
    "status": "Success",
    "command": "exists",
    "result": {
        "message": true
    }
}

Actual Behavior

fab exists / --output_format json
{
    "timestamp": "2025-12-29T16:42:07.387900Z",
    "status": "Success",
    "command": "exists",
    "result": {
        "message": "true"
    }
}

Additional Context

No response

Possible Solution

No response

[github-actions]

AI Assessment: Potential Bug

The report highlights that the fab exists command emits boolean values as JSON strings ("true"/"false") rather than native JSON booleans (true/false) when --output_format json is used. This violates expected JSON semantics per RFC 7159 (JSON), which requires booleans to be unquoted. The sample output demonstrates that type is lost, increasing risk of downstream logic errors in scripts and integrations.

The issue appears directly reproducible based on the command sample. The documented CLI output format (https://microsoft.github.io/fabric-cli/essentials/output_format/) is clear that valid JSON output is expected when --output_format json is specified. Presence of literal strings instead of booleans indicates a likely serialization bug or post-processing error.

No indication that this is caused by misconfiguration, as the config and flag usage are standard and the version is recent.

Next Steps
🔔 Escalated to team — This issue requires team review and has been flagged for attention.

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💡 If this issue requires the team's attention and was not escalated, you can tag @microsoft/fabric-cli-dev to notify the team.

[github-actions]

🔔 @microsoft/fabric-cli-dev — This issue has been flagged by AI triage as requiring team attention. Please review the assessment above.

[github-actions]

AI Assessment: Potential Bug

The report describes a discrepancy between expected and actual output format for the fab exists command when --output_format json is specified. Boolean results are rendered as strings ("true" or "false") rather than native JSON boolean values (true or false). This behaviour diverges from conventional JSON serialization and creates downstream usability and interoperability issues, especially in automation and scripting environments.

The CLI documentation specifies that output format can be json or text (https://microsoft.github.io/fabric-cli/essentials/output_format/), implying strict compliance with JSON standards (RFC 7159/8259). Returning a string where a boolean is expected is inconsistent with standard JSON behavior and can cause logic errors in consumer scripts (e.g., treating "false" as truthy). The issue is plausibly reproducible given the provided steps and output samples.

This does not appear to be a misconfiguration or a documented CLI limitation. Correction may require changes in the result serialization logic to ensure type fidelity.

Next Steps

🔔 Escalated to team — This issue requires team review and has been flagged for attention.

---

💡 If this issue requires the team's attention and was not escalated, you can tag @microsoft/fabric-cli-dev to notify the team.