Prevent reviewing courses for semesters that haven't started yet

[IshanA2007]

GitHub Issues addressed

• This PR closes Bug: Reviewing future courses #1252

What I did

Reviews could be placed for a course in a future semester (e.g. Fall 2026). Root cause: the review semester choices (recent_semesters() → semesters_for_course()) only had a lower year bound, and ReviewForm.clean() only validated that a matching Section existed. Production loads future-term sections for course registration, so those not-yet-started terms showed up as selectable and savable review options. (It didn't reproduce on older local data because that data simply lacked the future terms.)

The fix gates reviewable terms by the calendar date rather than by whatever is loaded in the DB (Semester.latest()):

• Semester.has_started() (models.py) — new SEASON_START_MONTH map + method; a term is "started" once its start month is reached in the current/prior year (Fall→Aug, Summer→May, Spring/January→Jan).
• utils.reviewable_semesters() — started-only subset of recent_semesters() (DB-level Case/When filter); semesters_for_course() now routes through it. recent_semesters() is intentionally left unchanged so the schedule builder still sees upcoming terms.
• ReviewForm.clean() — the real backend gate: rejects a not-yet-started term for both course and club reviews.
• UI filtering — the club dropdown (club_semester_choices_payload) and the empty-state / error-render semester lists in new_review.py now only offer started terms, so users never see an invalid option.

Screenshots

• Before — "Fall 2026" selectable as a review term; the review saves successfully.

• After — future terms no longer appear in the term dropdown, and are rejected server-side ("You can only review a semester that has already started.") even if forced.

Testing

Verified against a fresh prod dump (contains Fall 2026 = 9,038 sections). As of 2026-07-08: Fall 2026 has_started=False → excluded from reviewable_semesters() but still present in recent_semesters(); Summer 2026 / Spring 2026 remain reviewable.

Automated (full suite green — 265 tests):

• test_semester.HasStartedTestCase — unit tests for the date gate (past/future year, Fall-before-August, Summer-by-July, start-month boundary).
• test_review.ReviewFormSectionValidationTests — form rejects a future term (even with a matching section) and accepts a started term.
• test_review.ReviewCascadeJsonEndpointsTests — future terms excluded from semesters_for_course() and the review_semester_options XHR.

To test manually: pick a course with a Fall 2026 section under My Reviews → New Review; Fall 2026 should not be offered as a term.

Questions/Discussions/Notes

• Product call: a term becomes reviewable the moment it starts (so a summer term in progress is allowed). If we'd rather only allow reviewing a term once it has ended, that's a one-line change to the comparison in has_started().
• Season start months are approximate first-of-month values, which is sufficient for a future/past gate; they intentionally don't track exact UVA add/drop dates.

Summary by CodeRabbit

• New Features

  • Semester choices now only include terms that have already started.
  • Review forms now prevent creating reviews for future semesters.

• Bug Fixes

  • Improved semester start-date handling, including season-based start months and boundary-day behavior.
  • Review creation and semester selection now stay consistent across course and club review flows.

• Tests

  • Added coverage for semester start checks and future-semester review rejection.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: df6a8714-d8f0-4ef2-9ddb-1997c24d9ec2

📥 Commits

Reviewing files that changed from the base of the PR and between ed955fb and c6c4a49.

📒 Files selected for processing (7)

• tcf_website/models/models.py
• tcf_website/review/forms.py
• tcf_website/review/services.py
• tcf_website/tests/test_review.py
• tcf_website/tests/test_semester.py
• tcf_website/utils.py
• tcf_website/views/review/new_review.py

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📝 Walkthrough

Walkthrough

This PR adds a has_started() check to the Semester model based on a new season-to-start-month mapping, enforces it in ReviewForm validation to block reviews for future semesters, and introduces reviewable_semesters() used in services, views, and course semester lookups, with corresponding tests.

Changes

Restrict reviews and semester lists to started terms

Layer / File(s)	Summary
Semester start-month logic tcf_website/models/models.py, tcf_website/tests/test_semester.py	Adds SEASON_START_MONTH mapping and start_month()/has_started(as_of=None) methods to Semester; tests cover past/future years and inclusive boundary cases.
Form validation for future semesters tcf_website/review/forms.py, tcf_website/tests/test_review.py	ReviewForm.clean() raises ValidationError when the selected semester has not started; tests add a future-semester helper and verify rejection/acceptance behavior.
reviewable_semesters() filtering tcf_website/utils.py, tcf_website/tests/test_review.py	New reviewable_semesters() annotates semesters with a start month via Case/When and filters to already-started terms; semesters_for_course() now uses it; tests confirm future semesters are excluded from course/XHR results.
Service and view wiring tcf_website/review/services.py, tcf_website/views/review/new_review.py	club_semester_choices_payload() and review view context builders switch from recent_semesters() to reviewable_semesters().

Estimated code review effort: 2 (Simple) | ~15 minutes

Sequence Diagram(s)

sequenceDiagram
  participant User
  participant ReviewForm
  participant Semester
  participant NewReviewView

  User->>NewReviewView: Submit review with semester
  NewReviewView->>ReviewForm: clean()
  ReviewForm->>Semester: has_started()
  Semester-->>ReviewForm: True/False
  alt semester not started
    ReviewForm-->>NewReviewView: ValidationError
    NewReviewView-->>User: Re-render form with error
  else semester started
    ReviewForm-->>NewReviewView: Valid
    NewReviewView-->>User: Review saved
  end

Loading

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly summarizes the main change: blocking reviews for semesters that have not started yet.
Description check	✅ Passed	The description covers the issue, implementation, screenshots, testing, and follow-up notes in the required template sections.
Linked Issues check	✅ Passed	The PR addresses #1252 by preventing reviews for future semesters through model, form, and UI filtering changes.
Out of Scope Changes check	✅ Passed	The added changes and tests are all directly related to the future-semester review restriction.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

✨ 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 1252-bug-reviewing-future-courses

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