## Issue
#50013
## Description
The Microsoft compliance proxy controller
(`website/api/controllers/microsoft-proxy/receive-redirect-from-microsoft.js`)
called `JSON.parse` on response bodies from Microsoft's Partner
Compliance and Graph APIs without checking for empty bodies or
unexpected response shapes. When Microsoft returned an unexpected
response — for example, a 2xx status with an empty body, which can
happen on partial-setup tenant states or when API permissions on the
enterprise app haven't been fully consented — the controller threw a raw
`SyntaxError: Unexpected end of JSON input` that surfaced verbatim in
the Fleet UI as the `setup_error` string, giving admins a Node.js stack
trace instead of a useful message.
Changes:
- Added explicit empty-body checks before `JSON.parse` at both
API-response parse sites, with a friendly `setup_error` message pointing
at the likely causes (partial setup / missing API permissions).
- On parse failure, expanded the diagnostic log to include response
status code, body length, and a 200-char body snippet so we can diagnose
future occurrences from server logs instead of asking admins to
reproduce.
- Added defensive checks on `parsedPoliciesResponse.value` and
`parsedGroupResponse.value` before indexing — previously
`parsedPoliciesResponse.value[0].Id` would throw `TypeError` if
Microsoft returned a well-formed response missing the expected shape.
**Note for reviewers:** The new `sails.log.warn` calls interpolate the
runtime tenant ID (`informationAboutThisTenant.entraTenantId`) — same
pattern as the existing log at line 209 that logs `fleetInstanceUrl`.
Heroku logs will contain tenant IDs when these error paths fire, which
is intentional so infra can grep by tenant when triaging. If we'd rather
rely on request-correlation IDs and keep tenant IDs out of logs, happy
to make that a follow-up.
## Screenrecording
## Testing
- [ ] Sanity-checked locally by inducing an empty response body
- [ ] Verified no changes to the happy-path flow
- [ ] Verified existing setup_error strings that the Fleet UI checks for
(admin-did-not-consent, missing-conditional-access-group) are unchanged
<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit
* **Bug Fixes**
* Improved Microsoft integration setup handling when API responses are
empty, invalid, or missing expected data.
* Added clearer setup error messages for missing policies or the “Fleet
conditional access” group.
* Enhanced diagnostics to help identify response-related setup failures.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
RachelElysia
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