Fix non-deterministic empty flight fields via aria-label fallback

[LachyGroom]

Summary

• The HTML parser's CSS selectors (e.g. tPgKwe, mv1WYe, Ak5kof, BbR8Ec) intermittently fail because Google obfuscates class names differently depending on the browser/TLS fingerprint. Since primp's chrome_126 impersonation silently falls back to random, ~25% of requests return HTML with different class names — airline name, times, duration, and stops all come back empty while price (.YMlIz.FpEdX) still works.
• Adds a fallback that parses the aria-label attribute on each flight <li> when any CSS selector returns empty data. The aria-label always contains structured text like "Nonstop flight with Alaska. Leaves ... at 2:25 PM on Sunday, February 15 ..." regardless of which class names Google serves.
• Also handles U+202F (narrow no-break space) that Google uses between time digits and AM/PM in some responses (e.g. 2:25\u202fPM).

Reproduction

from fast_flights import FlightData, Passengers, get_flights

# Run this ~10 times — without the fix, ~25% of attempts return empty fields
result = get_flights(
    flight_data=[FlightData(date="2026-02-15", from_airport="SJC", to_airport="KOA")],
    trip="one-way", seat="business",
    passengers=Passengers(adults=2),
)
f = result.flights[0]
print(f.name, f.departure, f.arrival, f.duration, f.stops, f.price)
# Before fix: ''  ''  ''  ''  'Unknown'  '$2359'  (intermittent)
# After fix:  'Alaska'  '2:25 PM on Sun, Feb 15'  '6:13 PM on Sun, Feb 15'  '5 hr 48 min'  0  '$2359'  (always)

Related issues

• Update core.py price class #7 — Same class of bug (CSS class mismatch) previously fixed for price selector
• Duplicate flight entries appear in search results #63 — Duplicate flight entries from multiple container elements (IWWDBc + YdtKid)

Test plan

• 15/15 live requests pass with fix applied (vs 4 failures in 15 without)
• Verified against captured failing HTML — all 41 flights parse correctly
• Reviewed by OpenAI Codex — all flagged issues addressed
• Existing CSS-based parsing is unchanged; fallback only activates when fields are empty

Summary by CodeRabbit

• Bug Fixes
  • Improved flight data extraction reliability with a fallback parsing mechanism that activates when standard methods encounter missing or incomplete fields. Enhanced date formatting with abbreviated month and weekday names for better readability. These changes ensure consistent, accurate flight information retrieval across various website formats.

[coderabbitai]

📝 Walkthrough

Walkthrough

A new aria-label fallback mechanism is added to parse flight data when CSS selectors fail to capture essential fields. The implementation includes helper functions to extract flight details from structured aria-label attributes and format dates by abbreviating weekday and month names. The fallback activates conditionally only when primary CSS-based extraction yields missing or Unknown values.

Changes

Cohort / File(s)	Summary
Aria-label Fallback Parsing fast_flights/core.py	Added _parse_aria_label() function to extract flight name, departure, arrival, duration, and stops from HTML aria-label attributes. Introduced _shorten_date() helper with date abbreviation mappings (_DAY_ABBREVS, _MONTH_ABBREVS) for human-friendly formatting. Integrated fallback logic into main parsing flow to populate missing fields when CSS selectors miss data.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Poem

🐰 A fallback so clever, when CSS fades away,
Aria-labels whisper their secrets to say,
With abbreviated dates, like Sun and like Feb,
Flight data persists through the parsing web!

🚥 Pre-merge checks | ✅ 3 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 66.67% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately and concisely describes the main change: adding an aria-label fallback to fix empty flight fields caused by CSS selector failures.
Merge Conflict Detection	✅ Passed	✅ No merge conflicts detected when merging into main

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✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

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No actionable comments were generated in the recent review. 🎉

🧹 Recent nitpick comments

fast_flights/core.py (1)

356-374: Solid fallback integration with appropriate guards.

One minor consideration: the "flight" in aria check on lines 359 and 363 is case-sensitive. If Google ever capitalizes it (e.g., "Flight with…"), the fallback would silently skip. A lowercase comparison would be more defensive:

Optional: case-insensitive check

-                if not aria or "flight" not in aria:
-                    aria_el = item.css_first("[aria-label*='flight']")
+                aria_lower = aria.lower()
+                if not aria or "flight" not in aria_lower:
+                    aria_el = item.css_first("[aria-label*='flight'], [aria-label*='Flight']")
                     if aria_el:
                         aria = aria_el.attributes.get("aria-label", "") or ""
-                if aria and "flight" in aria:
+                if aria and "flight" in aria.lower():

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