spg-sql 7.39.6

Self-built SQL front-end for SPG: PG-dialect lexer + parser. no_std + alloc.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792

//! MySQL charset names and the collation each one defaults to.
//!
//! v7.39.2 — moved here from `spg-engine`'s `collate` because the
//! PARSER needs it: `_utf8mb4'x'` is a charset introducer only when the
//! word after the underscore names a charset, and deciding that is
//! parsing. The engine reads the same table through this module rather
//! than keeping a second copy — two lists of one fact is how the
//! surfaces in this release came to disagree in the first place.

/// Do trailing spaces count in a comparison under this collation?
///
/// v7.38.18 — the pad attribute is a property of the collation NAME,
/// and SPG read a name for whether to FOLD and never for whether to
/// PAD. `utf8mb4_bin` and `utf8mb4_general_ci` are PAD SPACE in BOTH
/// engines, which is the part that is easy to get backwards: byte-wise
/// does not mean padding counts.
///
/// The rule is measured, not inferred. Over every collation both
/// oracles list — 286 names on MySQL 9.7.2 and 552 on MariaDB 12.3.2,
/// 838 in all — `NO PAD` holds exactly when the name is `binary`, or
/// contains `_0900_`, or contains `nopad`. **Zero counter-examples on
/// either engine.**
///
/// `None` — nothing declared — is the session default, and SPG
/// advertises `8.0.0-spg-v…` on the MySQL wire, so that is MySQL 8.0's
/// `utf8mb4_0900_ai_ci`: NO PAD.
/// v7.39 — the collation a MySQL session compares under when the
/// session has not said otherwise.
///
/// One constant, because the last time a name SPG reports and a rule SPG
/// applies lived in two places they disagreed for months
/// (`server_version`, v7.38.25) -- and they disagreed here too:
/// `@@collation_connection` answered `utf8mb4_general_ci` (PAD SPACE)
/// while `e2e_mysql_pad_space_round375` pinned the NO PAD behaviour of
/// `utf8mb4_0900_ai_ci`, re-measured on MySQL 9.7.2 in v7.38.17. Both
/// were defensible on their own and could not both be right.
///
/// `utf8mb4_0900_ai_ci` is the value: it is what SPG's advertised 8.0
/// lineage implies, what `show.rs` already reported for
/// `collation_server`, what MySQL 9.7.2 answers for a bare
/// `SET NAMES utf8mb4` (measured -- and `'a' = 'a '` is 0 there), and
/// what those pins were re-measured against. `pads_space` reads
/// `_0900_` and says NO PAD, so the reported name and the applied rule
/// now agree by construction.
/// v7.39 — `SET NAMES <charset>` with no `COLLATE` takes the charset's
/// DEFAULT collation, and that decides whether the session pads.
/// Measured, not inferred: read from MySQL 9.7.2's
/// `information_schema.CHARACTER_SETS`, all 41 rows of it, so
/// the two that matter most are visible beside the rest --
/// `utf8mb4` -> `utf8mb4_0900_ai_ci` (NO PAD) and `latin1` ->
/// `latin1_swedish_ci` (PAD SPACE). Confirmed on the wire: a bare
/// `SET NAMES utf8mb4` answers `'a' = 'a '` with 0 there and a bare
/// `SET NAMES latin1` answers 1.
pub const MYSQL_CHARSET_DEFAULT_COLLATION: &[(&str, &str)] = &[
    ("armscii8", "armscii8_general_ci"),
    ("ascii", "ascii_general_ci"),
    ("big5", "big5_chinese_ci"),
    ("binary", "binary"),
    ("cp1250", "cp1250_general_ci"),
    ("cp1251", "cp1251_general_ci"),
    ("cp1256", "cp1256_general_ci"),
    ("cp1257", "cp1257_general_ci"),
    ("cp850", "cp850_general_ci"),
    ("cp852", "cp852_general_ci"),
    ("cp866", "cp866_general_ci"),
    ("cp932", "cp932_japanese_ci"),
    ("dec8", "dec8_swedish_ci"),
    ("eucjpms", "eucjpms_japanese_ci"),
    ("euckr", "euckr_korean_ci"),
    ("gb18030", "gb18030_chinese_ci"),
    ("gb2312", "gb2312_chinese_ci"),
    ("gbk", "gbk_chinese_ci"),
    ("geostd8", "geostd8_general_ci"),
    ("greek", "greek_general_ci"),
    ("hebrew", "hebrew_general_ci"),
    ("hp8", "hp8_english_ci"),
    ("keybcs2", "keybcs2_general_ci"),
    ("koi8r", "koi8r_general_ci"),
    ("koi8u", "koi8u_general_ci"),
    ("latin1", "latin1_swedish_ci"),
    ("latin2", "latin2_general_ci"),
    ("latin5", "latin5_turkish_ci"),
    ("latin7", "latin7_general_ci"),
    ("macce", "macce_general_ci"),
    ("macroman", "macroman_general_ci"),
    ("sjis", "sjis_japanese_ci"),
    ("swe7", "swe7_swedish_ci"),
    ("tis620", "tis620_thai_ci"),
    ("ucs2", "ucs2_general_ci"),
    ("ujis", "ujis_japanese_ci"),
    ("utf16", "utf16_general_ci"),
    ("utf16le", "utf16le_general_ci"),
    ("utf32", "utf32_general_ci"),
    ("utf8mb3", "utf8mb3_general_ci"),
    ("utf8mb4", "utf8mb4_0900_ai_ci"),
];

/// The collation `SET NAMES <charset>` selects, or `None` for a charset
/// this build does not know. An unknown name is not silently mapped to
/// a default: that is how a session ends up padding differently from
/// what it was told.
#[must_use]
pub fn charset_default_collation(charset: &str) -> Option<&'static str> {
    let lower = charset.trim().to_ascii_lowercase();
    MYSQL_CHARSET_DEFAULT_COLLATION
        .iter()
        .find(|(c, _)| *c == lower)
        .map(|(_, coll)| *coll)
}

/// Every collation MySQL 9.7.2 **or MariaDB 12.3.3** serves, read from
/// their own `information_schema.collations` — 575 names, sorted for
/// `binary_search`.
///
/// The union, because SPG answers to both. The first version was MySQL's
/// alone, and MariaDB's UCA-14.0.0 family — which MySQL does not have,
/// and which the drop-in acceptance suite declares its MariaDB column
/// with — became "no such collation". Every query against that table
/// then returned nothing: five drop-in cases failed at once, in CI, on a
/// suite the local gates do not run. 289 of these names are MariaDB's
/// alone and 23 are MySQL's.
///
/// v7.39.2 — the check this replaces was a SUFFIX: any name ending in
/// `_ci`, `_cs` or `_bin` counted as known. `SELECT 'a' COLLATE
/// nosuch_ci` was therefore accepted and then silently ignored — the
/// comparison did whatever the session would have done anyway, and a
/// client that named a collation got no signal that it had not been
/// used. MySQL 9.7.2 answers `ERROR 1273 (HY000): Unknown collation:
/// 'nosuch_ci'`.
pub const MYSQL_COLLATIONS: &[&str] = &[
    "armscii8_bin",
    "armscii8_general_ci",
    "armscii8_general_nopad_ci",
    "armscii8_nopad_bin",
    "ascii_bin",
    "ascii_general_ci",
    "ascii_general_nopad_ci",
    "ascii_nopad_bin",
    "big5_bin",
    "big5_chinese_ci",
    "big5_chinese_nopad_ci",
    "big5_nopad_bin",
    "binary",
    "cp1250_bin",
    "cp1250_croatian_ci",
    "cp1250_czech_cs",
    "cp1250_general_ci",
    "cp1250_general_nopad_ci",
    "cp1250_nopad_bin",
    "cp1250_polish_ci",
    "cp1251_bin",
    "cp1251_bulgarian_ci",
    "cp1251_general_ci",
    "cp1251_general_cs",
    "cp1251_general_nopad_ci",
    "cp1251_nopad_bin",
    "cp1251_ukrainian_ci",
    "cp1256_bin",
    "cp1256_general_ci",
    "cp1256_general_nopad_ci",
    "cp1256_nopad_bin",
    "cp1257_bin",
    "cp1257_general_ci",
    "cp1257_general_nopad_ci",
    "cp1257_lithuanian_ci",
    "cp1257_nopad_bin",
    "cp850_bin",
    "cp850_general_ci",
    "cp850_general_nopad_ci",
    "cp850_nopad_bin",
    "cp852_bin",
    "cp852_general_ci",
    "cp852_general_nopad_ci",
    "cp852_nopad_bin",
    "cp866_bin",
    "cp866_general_ci",
    "cp866_general_nopad_ci",
    "cp866_nopad_bin",
    "cp932_bin",
    "cp932_japanese_ci",
    "cp932_japanese_nopad_ci",
    "cp932_nopad_bin",
    "dec8_bin",
    "dec8_nopad_bin",
    "dec8_swedish_ci",
    "dec8_swedish_nopad_ci",
    "eucjpms_bin",
    "eucjpms_japanese_ci",
    "eucjpms_japanese_nopad_ci",
    "eucjpms_nopad_bin",
    "euckr_bin",
    "euckr_korean_ci",
    "euckr_korean_nopad_ci",
    "euckr_nopad_bin",
    "gb18030_bin",
    "gb18030_chinese_ci",
    "gb18030_unicode_520_ci",
    "gb2312_bin",
    "gb2312_chinese_ci",
    "gb2312_chinese_nopad_ci",
    "gb2312_nopad_bin",
    "gbk_bin",
    "gbk_chinese_ci",
    "gbk_chinese_nopad_ci",
    "gbk_nopad_bin",
    "geostd8_bin",
    "geostd8_general_ci",
    "geostd8_general_nopad_ci",
    "geostd8_nopad_bin",
    "greek_bin",
    "greek_general_ci",
    "greek_general_nopad_ci",
    "greek_nopad_bin",
    "hebrew_bin",
    "hebrew_general_ci",
    "hebrew_general_nopad_ci",
    "hebrew_nopad_bin",
    "hp8_bin",
    "hp8_english_ci",
    "hp8_english_nopad_ci",
    "hp8_nopad_bin",
    "keybcs2_bin",
    "keybcs2_general_ci",
    "keybcs2_general_nopad_ci",
    "keybcs2_nopad_bin",
    "koi8r_bin",
    "koi8r_general_ci",
    "koi8r_general_nopad_ci",
    "koi8r_nopad_bin",
    "koi8u_bin",
    "koi8u_general_ci",
    "koi8u_general_nopad_ci",
    "koi8u_nopad_bin",
    "latin1_bin",
    "latin1_danish_ci",
    "latin1_general_ci",
    "latin1_general_cs",
    "latin1_german1_ci",
    "latin1_german2_ci",
    "latin1_nopad_bin",
    "latin1_spanish_ci",
    "latin1_swedish_ci",
    "latin1_swedish_nopad_ci",
    "latin2_bin",
    "latin2_croatian_ci",
    "latin2_czech_cs",
    "latin2_general_ci",
    "latin2_general_nopad_ci",
    "latin2_hungarian_ci",
    "latin2_nopad_bin",
    "latin5_bin",
    "latin5_nopad_bin",
    "latin5_turkish_ci",
    "latin5_turkish_nopad_ci",
    "latin7_bin",
    "latin7_estonian_cs",
    "latin7_general_ci",
    "latin7_general_cs",
    "latin7_general_nopad_ci",
    "latin7_nopad_bin",
    "macce_bin",
    "macce_general_ci",
    "macce_general_nopad_ci",
    "macce_nopad_bin",
    "macroman_bin",
    "macroman_general_ci",
    "macroman_general_nopad_ci",
    "macroman_nopad_bin",
    "sjis_bin",
    "sjis_japanese_ci",
    "sjis_japanese_nopad_ci",
    "sjis_nopad_bin",
    "swe7_bin",
    "swe7_nopad_bin",
    "swe7_swedish_ci",
    "swe7_swedish_nopad_ci",
    "tis620_bin",
    "tis620_nopad_bin",
    "tis620_thai_ci",
    "tis620_thai_nopad_ci",
    "uca1400_ai_ci",
    "uca1400_ai_cs",
    "uca1400_as_ci",
    "uca1400_as_cs",
    "uca1400_croatian_ai_ci",
    "uca1400_croatian_ai_cs",
    "uca1400_croatian_as_ci",
    "uca1400_croatian_as_cs",
    "uca1400_croatian_nopad_ai_ci",
    "uca1400_croatian_nopad_ai_cs",
    "uca1400_croatian_nopad_as_ci",
    "uca1400_croatian_nopad_as_cs",
    "uca1400_czech_ai_ci",
    "uca1400_czech_ai_cs",
    "uca1400_czech_as_ci",
    "uca1400_czech_as_cs",
    "uca1400_czech_nopad_ai_ci",
    "uca1400_czech_nopad_ai_cs",
    "uca1400_czech_nopad_as_ci",
    "uca1400_czech_nopad_as_cs",
    "uca1400_danish_ai_ci",
    "uca1400_danish_ai_cs",
    "uca1400_danish_as_ci",
    "uca1400_danish_as_cs",
    "uca1400_danish_nopad_ai_ci",
    "uca1400_danish_nopad_ai_cs",
    "uca1400_danish_nopad_as_ci",
    "uca1400_danish_nopad_as_cs",
    "uca1400_esperanto_ai_ci",
    "uca1400_esperanto_ai_cs",
    "uca1400_esperanto_as_ci",
    "uca1400_esperanto_as_cs",
    "uca1400_esperanto_nopad_ai_ci",
    "uca1400_esperanto_nopad_ai_cs",
    "uca1400_esperanto_nopad_as_ci",
    "uca1400_esperanto_nopad_as_cs",
    "uca1400_estonian_ai_ci",
    "uca1400_estonian_ai_cs",
    "uca1400_estonian_as_ci",
    "uca1400_estonian_as_cs",
    "uca1400_estonian_nopad_ai_ci",
    "uca1400_estonian_nopad_ai_cs",
    "uca1400_estonian_nopad_as_ci",
    "uca1400_estonian_nopad_as_cs",
    "uca1400_german2_ai_ci",
    "uca1400_german2_ai_cs",
    "uca1400_german2_as_ci",
    "uca1400_german2_as_cs",
    "uca1400_german2_nopad_ai_ci",
    "uca1400_german2_nopad_ai_cs",
    "uca1400_german2_nopad_as_ci",
    "uca1400_german2_nopad_as_cs",
    "uca1400_hungarian_ai_ci",
    "uca1400_hungarian_ai_cs",
    "uca1400_hungarian_as_ci",
    "uca1400_hungarian_as_cs",
    "uca1400_hungarian_nopad_ai_ci",
    "uca1400_hungarian_nopad_ai_cs",
    "uca1400_hungarian_nopad_as_ci",
    "uca1400_hungarian_nopad_as_cs",
    "uca1400_icelandic_ai_ci",
    "uca1400_icelandic_ai_cs",
    "uca1400_icelandic_as_ci",
    "uca1400_icelandic_as_cs",
    "uca1400_icelandic_nopad_ai_ci",
    "uca1400_icelandic_nopad_ai_cs",
    "uca1400_icelandic_nopad_as_ci",
    "uca1400_icelandic_nopad_as_cs",
    "uca1400_latvian_ai_ci",
    "uca1400_latvian_ai_cs",
    "uca1400_latvian_as_ci",
    "uca1400_latvian_as_cs",
    "uca1400_latvian_nopad_ai_ci",
    "uca1400_latvian_nopad_ai_cs",
    "uca1400_latvian_nopad_as_ci",
    "uca1400_latvian_nopad_as_cs",
    "uca1400_lithuanian_ai_ci",
    "uca1400_lithuanian_ai_cs",
    "uca1400_lithuanian_as_ci",
    "uca1400_lithuanian_as_cs",
    "uca1400_lithuanian_nopad_ai_ci",
    "uca1400_lithuanian_nopad_ai_cs",
    "uca1400_lithuanian_nopad_as_ci",
    "uca1400_lithuanian_nopad_as_cs",
    "uca1400_nopad_ai_ci",
    "uca1400_nopad_ai_cs",
    "uca1400_nopad_as_ci",
    "uca1400_nopad_as_cs",
    "uca1400_persian_ai_ci",
    "uca1400_persian_ai_cs",
    "uca1400_persian_as_ci",
    "uca1400_persian_as_cs",
    "uca1400_persian_nopad_ai_ci",
    "uca1400_persian_nopad_ai_cs",
    "uca1400_persian_nopad_as_ci",
    "uca1400_persian_nopad_as_cs",
    "uca1400_polish_ai_ci",
    "uca1400_polish_ai_cs",
    "uca1400_polish_as_ci",
    "uca1400_polish_as_cs",
    "uca1400_polish_nopad_ai_ci",
    "uca1400_polish_nopad_ai_cs",
    "uca1400_polish_nopad_as_ci",
    "uca1400_polish_nopad_as_cs",
    "uca1400_roman_ai_ci",
    "uca1400_roman_ai_cs",
    "uca1400_roman_as_ci",
    "uca1400_roman_as_cs",
    "uca1400_roman_nopad_ai_ci",
    "uca1400_roman_nopad_ai_cs",
    "uca1400_roman_nopad_as_ci",
    "uca1400_roman_nopad_as_cs",
    "uca1400_romanian_ai_ci",
    "uca1400_romanian_ai_cs",
    "uca1400_romanian_as_ci",
    "uca1400_romanian_as_cs",
    "uca1400_romanian_nopad_ai_ci",
    "uca1400_romanian_nopad_ai_cs",
    "uca1400_romanian_nopad_as_ci",
    "uca1400_romanian_nopad_as_cs",
    "uca1400_sinhala_ai_ci",
    "uca1400_sinhala_ai_cs",
    "uca1400_sinhala_as_ci",
    "uca1400_sinhala_as_cs",
    "uca1400_sinhala_nopad_ai_ci",
    "uca1400_sinhala_nopad_ai_cs",
    "uca1400_sinhala_nopad_as_ci",
    "uca1400_sinhala_nopad_as_cs",
    "uca1400_slovak_ai_ci",
    "uca1400_slovak_ai_cs",
    "uca1400_slovak_as_ci",
    "uca1400_slovak_as_cs",
    "uca1400_slovak_nopad_ai_ci",
    "uca1400_slovak_nopad_ai_cs",
    "uca1400_slovak_nopad_as_ci",
    "uca1400_slovak_nopad_as_cs",
    "uca1400_slovenian_ai_ci",
    "uca1400_slovenian_ai_cs",
    "uca1400_slovenian_as_ci",
    "uca1400_slovenian_as_cs",
    "uca1400_slovenian_nopad_ai_ci",
    "uca1400_slovenian_nopad_ai_cs",
    "uca1400_slovenian_nopad_as_ci",
    "uca1400_slovenian_nopad_as_cs",
    "uca1400_spanish2_ai_ci",
    "uca1400_spanish2_ai_cs",
    "uca1400_spanish2_as_ci",
    "uca1400_spanish2_as_cs",
    "uca1400_spanish2_nopad_ai_ci",
    "uca1400_spanish2_nopad_ai_cs",
    "uca1400_spanish2_nopad_as_ci",
    "uca1400_spanish2_nopad_as_cs",
    "uca1400_spanish_ai_ci",
    "uca1400_spanish_ai_cs",
    "uca1400_spanish_as_ci",
    "uca1400_spanish_as_cs",
    "uca1400_spanish_nopad_ai_ci",
    "uca1400_spanish_nopad_ai_cs",
    "uca1400_spanish_nopad_as_ci",
    "uca1400_spanish_nopad_as_cs",
    "uca1400_swedish_ai_ci",
    "uca1400_swedish_ai_cs",
    "uca1400_swedish_as_ci",
    "uca1400_swedish_as_cs",
    "uca1400_swedish_nopad_ai_ci",
    "uca1400_swedish_nopad_ai_cs",
    "uca1400_swedish_nopad_as_ci",
    "uca1400_swedish_nopad_as_cs",
    "uca1400_turkish_ai_ci",
    "uca1400_turkish_ai_cs",
    "uca1400_turkish_as_ci",
    "uca1400_turkish_as_cs",
    "uca1400_turkish_nopad_ai_ci",
    "uca1400_turkish_nopad_ai_cs",
    "uca1400_turkish_nopad_as_ci",
    "uca1400_turkish_nopad_as_cs",
    "uca1400_vietnamese_ai_ci",
    "uca1400_vietnamese_ai_cs",
    "uca1400_vietnamese_as_ci",
    "uca1400_vietnamese_as_cs",
    "uca1400_vietnamese_nopad_ai_ci",
    "uca1400_vietnamese_nopad_ai_cs",
    "uca1400_vietnamese_nopad_as_ci",
    "uca1400_vietnamese_nopad_as_cs",
    "ucs2_bin",
    "ucs2_croatian_ci",
    "ucs2_croatian_mysql561_ci",
    "ucs2_czech_ci",
    "ucs2_danish_ci",
    "ucs2_esperanto_ci",
    "ucs2_estonian_ci",
    "ucs2_general_ci",
    "ucs2_general_mysql500_ci",
    "ucs2_general_nopad_ci",
    "ucs2_german2_ci",
    "ucs2_hungarian_ci",
    "ucs2_icelandic_ci",
    "ucs2_latvian_ci",
    "ucs2_lithuanian_ci",
    "ucs2_myanmar_ci",
    "ucs2_nopad_bin",
    "ucs2_persian_ci",
    "ucs2_polish_ci",
    "ucs2_roman_ci",
    "ucs2_romanian_ci",
    "ucs2_sinhala_ci",
    "ucs2_slovak_ci",
    "ucs2_slovenian_ci",
    "ucs2_spanish2_ci",
    "ucs2_spanish_ci",
    "ucs2_swedish_ci",
    "ucs2_thai_520_w2",
    "ucs2_turkish_ci",
    "ucs2_unicode_520_ci",
    "ucs2_unicode_520_nopad_ci",
    "ucs2_unicode_ci",
    "ucs2_unicode_nopad_ci",
    "ucs2_vietnamese_ci",
    "ujis_bin",
    "ujis_japanese_ci",
    "ujis_japanese_nopad_ci",
    "ujis_nopad_bin",
    "utf16_bin",
    "utf16_croatian_ci",
    "utf16_croatian_mysql561_ci",
    "utf16_czech_ci",
    "utf16_danish_ci",
    "utf16_esperanto_ci",
    "utf16_estonian_ci",
    "utf16_general_ci",
    "utf16_general_nopad_ci",
    "utf16_german2_ci",
    "utf16_hungarian_ci",
    "utf16_icelandic_ci",
    "utf16_latvian_ci",
    "utf16_lithuanian_ci",
    "utf16_myanmar_ci",
    "utf16_nopad_bin",
    "utf16_persian_ci",
    "utf16_polish_ci",
    "utf16_roman_ci",
    "utf16_romanian_ci",
    "utf16_sinhala_ci",
    "utf16_slovak_ci",
    "utf16_slovenian_ci",
    "utf16_spanish2_ci",
    "utf16_spanish_ci",
    "utf16_swedish_ci",
    "utf16_thai_520_w2",
    "utf16_turkish_ci",
    "utf16_unicode_520_ci",
    "utf16_unicode_520_nopad_ci",
    "utf16_unicode_ci",
    "utf16_unicode_nopad_ci",
    "utf16_vietnamese_ci",
    "utf16le_bin",
    "utf16le_general_ci",
    "utf16le_general_nopad_ci",
    "utf16le_nopad_bin",
    "utf32_bin",
    "utf32_croatian_ci",
    "utf32_croatian_mysql561_ci",
    "utf32_czech_ci",
    "utf32_danish_ci",
    "utf32_esperanto_ci",
    "utf32_estonian_ci",
    "utf32_general_ci",
    "utf32_general_nopad_ci",
    "utf32_german2_ci",
    "utf32_hungarian_ci",
    "utf32_icelandic_ci",
    "utf32_latvian_ci",
    "utf32_lithuanian_ci",
    "utf32_myanmar_ci",
    "utf32_nopad_bin",
    "utf32_persian_ci",
    "utf32_polish_ci",
    "utf32_roman_ci",
    "utf32_romanian_ci",
    "utf32_sinhala_ci",
    "utf32_slovak_ci",
    "utf32_slovenian_ci",
    "utf32_spanish2_ci",
    "utf32_spanish_ci",
    "utf32_swedish_ci",
    "utf32_thai_520_w2",
    "utf32_turkish_ci",
    "utf32_unicode_520_ci",
    "utf32_unicode_520_nopad_ci",
    "utf32_unicode_ci",
    "utf32_unicode_nopad_ci",
    "utf32_vietnamese_ci",
    "utf8mb3_bin",
    "utf8mb3_croatian_ci",
    "utf8mb3_croatian_mysql561_ci",
    "utf8mb3_czech_ci",
    "utf8mb3_danish_ci",
    "utf8mb3_esperanto_ci",
    "utf8mb3_estonian_ci",
    "utf8mb3_general1400_as_ci",
    "utf8mb3_general_ci",
    "utf8mb3_general_mysql500_ci",
    "utf8mb3_general_nopad_ci",
    "utf8mb3_german2_ci",
    "utf8mb3_hungarian_ci",
    "utf8mb3_icelandic_ci",
    "utf8mb3_latvian_ci",
    "utf8mb3_lithuanian_ci",
    "utf8mb3_myanmar_ci",
    "utf8mb3_nopad_bin",
    "utf8mb3_persian_ci",
    "utf8mb3_polish_ci",
    "utf8mb3_roman_ci",
    "utf8mb3_romanian_ci",
    "utf8mb3_sinhala_ci",
    "utf8mb3_slovak_ci",
    "utf8mb3_slovenian_ci",
    "utf8mb3_spanish2_ci",
    "utf8mb3_spanish_ci",
    "utf8mb3_swedish_ci",
    "utf8mb3_thai_520_w2",
    "utf8mb3_tolower_ci",
    "utf8mb3_turkish_ci",
    "utf8mb3_unicode_520_ci",
    "utf8mb3_unicode_520_nopad_ci",
    "utf8mb3_unicode_ci",
    "utf8mb3_unicode_nopad_ci",
    "utf8mb3_vietnamese_ci",
    "utf8mb4_0900_ai_ci",
    "utf8mb4_0900_as_ci",
    "utf8mb4_0900_as_cs",
    "utf8mb4_0900_bin",
    "utf8mb4_bg_0900_ai_ci",
    "utf8mb4_bg_0900_as_cs",
    "utf8mb4_bin",
    "utf8mb4_bs_0900_ai_ci",
    "utf8mb4_bs_0900_as_cs",
    "utf8mb4_croatian_ci",
    "utf8mb4_croatian_mysql561_ci",
    "utf8mb4_cs_0900_ai_ci",
    "utf8mb4_cs_0900_as_cs",
    "utf8mb4_czech_ci",
    "utf8mb4_da_0900_ai_ci",
    "utf8mb4_da_0900_as_cs",
    "utf8mb4_danish_ci",
    "utf8mb4_de_pb_0900_ai_ci",
    "utf8mb4_de_pb_0900_as_cs",
    "utf8mb4_eo_0900_ai_ci",
    "utf8mb4_eo_0900_as_cs",
    "utf8mb4_es_0900_ai_ci",
    "utf8mb4_es_0900_as_cs",
    "utf8mb4_es_trad_0900_ai_ci",
    "utf8mb4_es_trad_0900_as_cs",
    "utf8mb4_esperanto_ci",
    "utf8mb4_estonian_ci",
    "utf8mb4_et_0900_ai_ci",
    "utf8mb4_et_0900_as_cs",
    "utf8mb4_general1400_as_ci",
    "utf8mb4_general_ci",
    "utf8mb4_general_nopad_ci",
    "utf8mb4_german2_ci",
    "utf8mb4_gl_0900_ai_ci",
    "utf8mb4_gl_0900_as_cs",
    "utf8mb4_hr_0900_ai_ci",
    "utf8mb4_hr_0900_as_cs",
    "utf8mb4_hu_0900_ai_ci",
    "utf8mb4_hu_0900_as_cs",
    "utf8mb4_hungarian_ci",
    "utf8mb4_icelandic_ci",
    "utf8mb4_is_0900_ai_ci",
    "utf8mb4_is_0900_as_cs",
    "utf8mb4_ja_0900_as_cs",
    "utf8mb4_ja_0900_as_cs_ks",
    "utf8mb4_la_0900_ai_ci",
    "utf8mb4_la_0900_as_cs",
    "utf8mb4_latvian_ci",
    "utf8mb4_lithuanian_ci",
    "utf8mb4_lt_0900_ai_ci",
    "utf8mb4_lt_0900_as_cs",
    "utf8mb4_lv_0900_ai_ci",
    "utf8mb4_lv_0900_as_cs",
    "utf8mb4_mn_cyrl_0900_ai_ci",
    "utf8mb4_mn_cyrl_0900_as_cs",
    "utf8mb4_myanmar_ci",
    "utf8mb4_nb_0900_ai_ci",
    "utf8mb4_nb_0900_as_cs",
    "utf8mb4_nn_0900_ai_ci",
    "utf8mb4_nn_0900_as_cs",
    "utf8mb4_nopad_bin",
    "utf8mb4_persian_ci",
    "utf8mb4_pl_0900_ai_ci",
    "utf8mb4_pl_0900_as_cs",
    "utf8mb4_polish_ci",
    "utf8mb4_ro_0900_ai_ci",
    "utf8mb4_ro_0900_as_cs",
    "utf8mb4_roman_ci",
    "utf8mb4_romanian_ci",
    "utf8mb4_ru_0900_ai_ci",
    "utf8mb4_ru_0900_as_cs",
    "utf8mb4_sinhala_ci",
    "utf8mb4_sk_0900_ai_ci",
    "utf8mb4_sk_0900_as_cs",
    "utf8mb4_sl_0900_ai_ci",
    "utf8mb4_sl_0900_as_cs",
    "utf8mb4_slovak_ci",
    "utf8mb4_slovenian_ci",
    "utf8mb4_spanish2_ci",
    "utf8mb4_spanish_ci",
    "utf8mb4_sr_latn_0900_ai_ci",
    "utf8mb4_sr_latn_0900_as_cs",
    "utf8mb4_sv_0900_ai_ci",
    "utf8mb4_sv_0900_as_cs",
    "utf8mb4_swedish_ci",
    "utf8mb4_thai_520_w2",
    "utf8mb4_tr_0900_ai_ci",
    "utf8mb4_tr_0900_as_cs",
    "utf8mb4_turkish_ci",
    "utf8mb4_unicode_520_ci",
    "utf8mb4_unicode_520_nopad_ci",
    "utf8mb4_unicode_ci",
    "utf8mb4_unicode_nopad_ci",
    "utf8mb4_vi_0900_ai_ci",
    "utf8mb4_vi_0900_as_cs",
    "utf8mb4_vietnamese_ci",
    "utf8mb4_zh_0900_as_cs",
];

/// The character sets MariaDB lets the UCA-14.0.0 family be written
/// against, measured on 12.3.3 by asking it: `utf8mb4_uca1400_ai_ci`
/// and four more resolve, `latin1_uca1400_ai_ci` does not.
const UCA_PREFIX_CHARSETS: &[&str] = &["ucs2", "utf16", "utf32", "utf8mb3", "utf8mb4"];

/// Is this a collation name MySQL or MariaDB serves?
///
/// MariaDB registers the UCA-14.0.0 family WITHOUT a character set —
/// `information_schema.collations` lists `uca1400_ai_ci`, not
/// `utf8mb4_uca1400_ai_ci` — and accepts either spelling in SQL. The
/// table alone therefore refused the spelling everything is written
/// with; the prefix form is checked against the same table with the
/// charset removed, and only for the five character sets MariaDB
/// actually resolves it for.
#[must_use]
pub fn is_mysql_collation(name: &str) -> bool {
    let lower = name.trim().to_ascii_lowercase();
    if MYSQL_COLLATIONS.binary_search(&lower.as_str()).is_ok() {
        return true;
    }
    UCA_PREFIX_CHARSETS.iter().any(|cs| {
        lower
            .strip_prefix(cs)
            .and_then(|rest| rest.strip_prefix('_'))
            .is_some_and(|rest| {
                rest.starts_with("uca1400") && MYSQL_COLLATIONS.binary_search(&rest).is_ok()
            })
    })
}

#[cfg(test)]
mod mysql_collation_tests {
    use super::{MYSQL_COLLATIONS, is_mysql_collation};

    /// `binary_search` is only an answer if the list is in byte order,
    /// and MySQL's own `ORDER BY` is not byte order — the first version
    /// of this table was written in the order the server returned and
    /// would have missed names in the middle of it.
    #[test]
    fn the_table_is_sorted_and_lowercase() {
        let mut sorted = MYSQL_COLLATIONS.to_vec();
        sorted.sort_unstable();
        assert_eq!(sorted.as_slice(), MYSQL_COLLATIONS, "not in byte order");
        assert!(
            MYSQL_COLLATIONS
                .iter()
                .all(|c| c.to_ascii_lowercase() == **c),
            "a name is not lowercase, so the lookup would miss it"
        );
        // Every one of them must be findable, which a wrong order breaks
        // silently for exactly the names a suffix rule already accepted.
        assert!(MYSQL_COLLATIONS.iter().all(|c| is_mysql_collation(c)));
    }

    #[test]
    fn it_answers_the_names_the_suffix_rule_could_not_tell_apart() {
        assert!(is_mysql_collation("utf8mb4_general_ci"));
        assert!(is_mysql_collation("utf8mb4_0900_ai_ci"));
        assert!(is_mysql_collation("UTF8MB4_BIN"));
        assert!(is_mysql_collation("binary"));
        assert!(is_mysql_collation("latin1_swedish_ci"));
        // All three suffixes the old rule waved through.
        assert!(!is_mysql_collation("nosuch_ci"));
        assert!(!is_mysql_collation("nosuch_cs"));
        assert!(!is_mysql_collation("nosuch_bin"));
        // And a real charset with a family neither engine has.
        assert!(!is_mysql_collation("utf8mb4_madeup_ci"));
    }

    /// MariaDB's UCA-14.0.0 family, which it registers without a
    /// character set and accepts with or without one. Every expectation
    /// measured on MariaDB 12.3.3.
    #[test]
    fn the_uca1400_family_is_known_in_both_spellings() {
        assert!(is_mysql_collation("uca1400_ai_ci"));
        assert!(is_mysql_collation("utf8mb4_uca1400_ai_ci"));
        assert!(is_mysql_collation("utf8mb3_uca1400_as_cs"));
        // `latin1` has no UCA collation and MariaDB refuses this one, so
        // a rule that just stripped any prefix would be wrong.
        assert!(!is_mysql_collation("latin1_uca1400_ai_ci"));
        // And the family name still has to be one that exists.
        assert!(!is_mysql_collation("utf8mb4_nosuch1400_ai_ci"));
        assert!(!is_mysql_collation("utf8mb4_uca1400_nosuch"));
    }
}