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Fix check_marttra() Thai final consonant classification#1173

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copilot/fix-check-marttra-bug
Jan 6, 2026
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Fix check_marttra() Thai final consonant classification#1173
wannaphong merged 4 commits intodevfrom
copilot/fix-check-marttra-bug

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Copilot AI commented Jan 6, 2026 •
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What does this changes

Fixes Thai final consonant classification in KhaveeVerifier.check_marttra() for poetry analysis. Ten test cases involving ำ, การันต์ (์), consonant clusters, and ไ/ใ+ย/ล patterns now return correct มาตรา (marttra) values.

What was wrong

  1. การันต์ (์) handling: handle_karun_sound_silence() removed incorrect number of characters - complex logic miscalculated cutoff positions
  2. ำ finals: Treated as open syllable (กา) instead of m-final (กม)
  3. Consonant clusters: Words like จักร (กร cluster) classified by ร alone, not recognizing cluster as k-final
  4. ไ/ใ + ย/ล ambiguity: No distinction between ย/ล as vowel component (ไก่ → กา) vs. true final consonant (ไกล → เกย)
  5. Typo: ", ณ" in consonant list

How this fixes it

Simplified การันต์ handling: Remove ์ and preceding character uniformly

# Before: Complex logic with consonant checks
# After:
word = word[:-2]  # รมย์ → รม, โยชน์ → โยช

Added special cases:

  • Check ำ first → return กม immediately
  • Detect กร/ขร/คร/ฆร clusters in 3+ char words → remove ร before classification

ไ/ใ + ย/ล disambiguation: Count consonants to determine if ย/ล is true final

def _has_true_final_yl(word):
    consonant_count = sum(1 for c in word if c in thai_consonants)
    return consonant_count >= 2 and word[-1] in ["ย", "ล"]

# ไก่ (1 consonant) → ย is vowel component → กา
# ไกล (2 consonants) → ล is true final → เกย

Code quality: Use imported thai_consonants constant, fix typo, remove redundant ล from กน list

Your checklist for this pull request

  • Passed code styles and structures
  • Passed code linting checks and unit test
Original prompt

This section details on the original issue you should resolve

<issue_title>bug: check_marttra("จักร") returns "กน"</issue_title>
<issue_description>### Description

check_marttra() method in pythainlp.khavee.KhaveeVerifier does not properly handel "กร" as a final consonant.

Expected results

check_marttra("จักร") returns "กก"

Current results

check_marttra("จักร") returns "กน"

See a run in PR #967 at https://github.com/PyThaiNLP/pythainlp/actions/runs/11641064036/job/32419112079?pr=967

Steps to reproduce

from pythainlp.khavee import KhaveeVerifier

kv = KhaveeVerifier()

kv.check_marttra("จักร")

PyThaiNLP version

5.0.4

More cases

All of these following test cases at

pythainlp/tests/test_khavee.py

Line 16 in 0c970fd

def test_check_marttra(self):
are failed.

        self.assertEqual(kv.check_marttra("ขำ"), "กม")
        self.assertEqual(kv.check_marttra("รมย์"), "กม")

        self.assertEqual(kv.check_marttra("ทัย"), "เกย")
        self.assertEqual(kv.check_marttra("ไทย"), "เกย")
        self.assertEqual(kv.check_marttra("ไกล"), "เกย")
        self.assertEqual(kv.check_marttra("ใกล้"), "เกย")

        self.assertEqual(kv.check_marttra("จักร"), "กก")

        self.assertEqual(kv.check_marttra("โยชน์"), "กด")

        self.assertEqual(kv.check_marttra("ยนต์"), "กน")
        self.assertEqual(kv.check_marttra("กรรณ"), "กน")
```</issue_description>

## Comments on the Issue (you are @copilot in this section)

<comments>
<comment_new><author>@wannaphong</author><body>
@kangkengkhadev @S2P2 Can you help this issue?</body></comment_new>
</comments>

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

Copilot AI and others added 3 commits January 6, 2026 10:48
@wannaphong
Fix check_marttra function to handle Thai final consonants correctly
ef020a1 
- Fixed handle_karun_sound_silence to correctly remove only silent consonants marked by ์
- Fixed handling of ำ at the end to return กม (not กา)
- Fixed handling of consonant clusters with ร (e.g., กร, ขร, คร) in compound words
- Fixed handling of words with ไ/ใ vowels to distinguish true final consonants ย/ล from vowel components
- Fixed typo in consonant list (", ณ" -> "ณ")
- Uncommented all previously failing test cases

Co-authored-by: wannaphong <8536487+wannaphong@users.noreply.github.com>
@wannaphong
Address code review feedback
ff3a4c3 
- Remove duplicate ล from กน consonant list (already classified as เกย on line 282)
- Use imported thai_consonants constant instead of duplicating the string
- Improves code maintainability and eliminates redundancy

Co-authored-by: wannaphong <8536487+wannaphong@users.noreply.github.com>
@wannaphong
Optimize helper function by moving to class method
4019183 
- Moved has_true_final_yl from inline function to class method _has_true_final_yl
- Avoids recreating function object on every check_marttra call
- Improves performance and code organization

Co-authored-by: wannaphong <8536487+wannaphong@users.noreply.github.com>
@sonarqubecloud
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sonarqubecloud bot commented Jan 6, 2026

Quality Gate Passed Quality Gate passed

Issues
3 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

Copilot AI changed the title [WIP] Fix check_marttra method to correctly handle final consonant Fix check_marttra() Thai final consonant classification Jan 6, 2026
Copilot AI requested a review from wannaphong January 6, 2026 10:59
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coveralls commented Jan 6, 2026

Coverage Status

coverage: 52.597% (+0.1%) from 52.461%
when pulling 4019183 on copilot/fix-check-marttra-bug
into de6be60 on dev.

@wannaphong wannaphong marked this pull request as ready for review January 6, 2026 11:31
@wannaphong wannaphong merged commit 41ed2c8 into dev Jan 6, 2026
43 of 44 checks passed
@wannaphong wannaphong added this to the 5.3 milestone Jan 6, 2026
@wannaphong wannaphong mentioned this pull request Jan 13, 2026
Closed
@bact bact deleted the copilot/fix-check-marttra-bug branch January 14, 2026 16:56
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bug: check_marttra("จักร") returns "กน"

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