fix(clinical): detect duplicate schedules by SQL error number

[rlorenzo]

What

In ScheduleEditService.AddInstructorAsync, the post-SaveChanges catch decides whether a DB failure means "instructor already scheduled" by SQL Server error number (2627 unique-constraint, 2601 duplicate-key-in-unique-index) instead of substring-matching the exception message.

private static bool IsDuplicateKeyViolation(Exception ex)
{
    var sqlEx = ex as SqlException ?? ex.InnerException as SqlException;
    return sqlEx is not null
        && sqlEx.Errors.Cast<SqlError>().Any(e => e.Number is 2627 or 2601);
}

Why

The old check matched "duplicate" / "unique" / "constraint" / "violation of primary key" against message.ToLower(). Two problems:

1. Latent bug: other constraint failures — foreign-key or check-constraint violations (error 547, whose message contains "constraint") — were mis-reported as "already scheduled." Now only true duplicate/unique violations get that message; everything else falls through to the generic "database operation failed" message.
2. Locale fragility: ToLower() plus English error-text matching is culture-sensitive (Turkish-I) and breaks if SQL messages are localized. Error numbers are stable and locale-invariant.

Notes

• Behavior-preserving for the real duplicate case; only re-routes non-duplicate constraint errors to the correct (generic) message.
• The duplicate pre-check (before SaveChanges) is unchanged; AddInstructorAsync_WithScheduleConflicts and all 2084 tests pass.
• Supersedes the message-matching helper currently on Development via refactor(codeql): decompose complex conditions + harden Vite web-root check #227; the overlap will be resolved (keeping this version) at the Development merge.

[codecov-commenter]

Bundle Report

Bundle size has no change ✅

[codecov-commenter]

Codecov Report

❌ Patch coverage is 83.33333% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 44.53%. Comparing base (1a0996e) to head (b9765ea).

Files with missing lines	Patch %	Lines
.../ClinicalScheduler/Services/ScheduleEditService.cs	83.33%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #229      +/-   ##
==========================================
+ Coverage   44.51%   44.53%   +0.01%     
==========================================
  Files         895      895              
  Lines       51760    51759       -1     
  Branches     4827     4828       +1     
==========================================
+ Hits        23041    23050       +9     
+ Misses      28149    28138      -11     
- Partials      570      571       +1     

Flag	Coverage Δ
backend	44.69% <83.33%> (+0.01%)	⬆️
frontend	41.32% <ø> (ø)

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[Copilot]

Pull request overview

Refines error handling in the Clinical Scheduler’s ScheduleEditService.AddInstructorAsync so that “already scheduled” is only returned for true SQL Server duplicate/unique key violations, using stable SQL error numbers instead of locale-dependent substring matching on exception messages.

Changes:

• Replaces exception message substring matching with SQL Server error-number detection (2627, 2601) to identify duplicate-key violations.
• Adds a focused helper (IsDuplicateKeyViolation) to unwrap EF/SQL exceptions and check SqlException.Errors.

[rlorenzo]

@coderabbitai full review

[coderabbitai]

✅ Action performed

Full review finished.

[coderabbitai]

📝 Walkthrough

Walkthrough

AddInstructorAsync now detects SQL Server duplicate-key violations by error number instead of exception-message text, returning the existing “already scheduled” error for those cases and a generic database failure for other exceptions.

Changes

Duplicate-key error classification

Layer / File(s)	Summary
Duplicate-key classification web/Areas/ClinicalScheduler/Services/ScheduleEditService.cs	AddInstructorAsync now calls IsDuplicateKeyViolation inside its database-exception catch path, and the new helper checks SqlException.Errors for SQL Server error numbers 2627 and 2601.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Possibly related PRs

• ucdavis/VIPER#193: Related ScheduleEditService exception-handling changes around SQL-specific duplicate/unique key handling.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 33.33% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly summarizes the main change: duplicate schedule detection now uses SQL error numbers.
Description check	✅ Passed	The description matches the code change and explains the SQL error-number-based duplicate detection.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/clinical-duplicate-key-detection

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@web/Areas/ClinicalScheduler/Services/ScheduleEditService.cs`:
- Around line 250-252: Add targeted tests for the exception classification logic
in IsDuplicateKeyViolation within ScheduleEditService so both branches are
covered. Create tests that feed the service a duplicate-key SqlException with
error numbers 2627 and 2601 and verify the duplicate-schedule path, plus a
non-duplicate SqlException/DbUpdateException that verifies the generic
database-failure path. Make sure the tests assert the downstream API error
mapping contract stays distinct for these two cases.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: ASSERTIVE

Plan: Pro

Run ID: 109ef738-ea05-4f15-b163-60f3a498908e

📥 Commits

Reviewing files that changed from the base of the PR and between 1a0996e and 06ab238.

📒 Files selected for processing (1)

• web/Areas/ClinicalScheduler/Services/ScheduleEditService.cs

[Copilot]

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.