Merge the 24:00:00 fix from branch-3.54 into trunk

FossilOrigin-Name: 3ce64081cab882b60ad73db77da961e479cd84eb151444f420da9fcc370f740d

manifest

@@ -1,5 +1,5 @@
-C Ensure\sthe\scorrect\scollation\ssequence\sis\sused\sfor\sexpressions\slike\s"a\sIN\s(SELECT\sb\sCOLLATE\s...)"\swhen\susing\san\sindex\son\s"a".\sBug\s[bugs:/info/2026-10-14T18:00:55Z\s|\s2026-10-14T18:00:55Z].
-D 2026-10-14T20:07:19.081
+C Merge\sthe\s24:00:00\sfix\sfrom\sbranch-3.54\sinto\strunk
+D 2026-10-15T13:33:20.847
 F .fossil-settings/binary-glob 61195414528fb3ea9693577e1980230d78a1f8b0a54c78cf1b9b24d0a409ed6a x
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
@@ -751,7 +751,7 @@ F src/build.c 1406d252bc5b2c3f2150edd4426e5981eabf1000944be8db8d470b96eb64ee07
 F src/callback.c 3605bbf02bd7ed46c79cd48346db4a32fc51d67624400539c0532f4eead804ad
 F src/carray.c 22879bbd9e14fc4868f223b0d49bcdbbda4616c89f1519ec6a5e64b98a4137b1
 F src/complete.c f68f545b9c6c19e2e848672dc0e4da230072fedc335d8980b55242cc4cfa60da
-F src/date.c 080641f59097d14fc7341f8bc0458d273b3a62d8381916db8ccbc89c2aae07b3
+F src/date.c 7719f64947e718a38897af459259eeac1aeda7daf7b87860c4d37fc687101004
 F src/dbpage.c ec8590c5e7a564cef28ca3c6156521316a4d26cb572a34841b0bcb26b67b3f97
 F src/dbstat.c 34d4e825fbf763640ce3dbc56910ab080495ef4a6efb48b2b1852a43d43763fc
 F src/delete.c f3f07c1fb6ac87fac2425d48fd40ecb2f24a4495a9966f5a939668d3576916c8
@@ -1107,7 +1107,7 @@ F test/ctime.test 340f362f41f92972bbd71f44e10569a5cc694062b692231bd08aa6fe6c1c47
 F test/cursorhint.test d8b93ac48dfdb2cf4284142710d63e860b6497afff2e9c525daf752a229e5b97
 F test/cursorhint2.test a10f29c0c52d4d73c19cf639f3c33cccbf5024bcf950fa48f2a8cdc14628b985
 F test/dataversion1.test 6e5e86ac681f0782e766ebcb56c019ae001522d114e0e111e5ebf68ccf2a7bb8
-F test/date.test d345d7905b6a212ced06efd6c236da0745f0f488e8d46df83940956b573adbc0
+F test/date.test e71d1c3640a6d1a59a8ea94b52dbe934ecaaeecd9e9db73ee1d10d27a5a6aece
 F test/date2.test 7e12ec14aaf4d5e6294b4ba140445b0eca06ea50062a9c3a69c4ee13d0b6f8b1
 F test/date3.test a1b77abf05c6772fe5ca2337cac1398892f2a41e62bce7e6be0f4a08a0e64ae5
 F test/date4.test b5ad22baf7394e008ac59383840159daedd45be31dcf74a3b2450ec0e28955ce
@@ -2289,8 +2289,8 @@ F tool/warnings-clang.sh bbf6a1e685e534c92ec2bfba5b1745f34fb6f0bc2a362850723a9ee
 F tool/warnings.sh a554d13f6e5cf3760f041b87939e3d616ec6961859c3245e8ef701d1eafc2ca2
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
 F tool/winmain.c 00c8fb88e365c9017db14c73d3c78af62194d9644feaf60e220ab0f411f3604c
-P 7408f90ecc2dd26aceb52f92de78b8e1521cb5a294d3231fd32a903afe1db41d
-R 5f6bbf38b99d69e3dd5ddb9061ec4c5c
-U dan
-Z 35b9fc891349c0ce95466fe213532097
+P bbdd13370de9303561bf501f88bf62d2ba363c6e5d950d8d7416e59874768ee0 69071e25cad52b7fe15749f5fb969e847f9cd65e66341e8d1d4e5f5282283cd4
+R 997bf1f7e3f0c95c82dc0a4870242ace
+U drh
+Z 0c8a9a0f0e92ca8d8f1848fdc3b11728
 # Remove this line to create a well-formed Fossil manifest.

manifest.uuid

@@ -1 +1 @@
-bbdd13370de9303561bf501f88bf62d2ba363c6e5d950d8d7416e59874768ee0
+3ce64081cab882b60ad73db77da961e479cd84eb151444f420da9fcc370f740d

src/date.c

@@ -302,6 +302,21 @@ static void computeJD(DateTime *p){
   }
 }
 
+/*
+** Return the number of dates in a specific month.
+*/
+static int daysOfMonth(int Y, int M){
+  if( (1<<M) & 0x15aa ){
+    return 31;
+  }else if( M!=2 ){
+    return 30;
+  }else if( Y%4==0 && (Y%100!=0 || Y%400==0) ){
+    return 29;
+  }else{
+    return 28;
+  }
+}
+
 /*
 ** Given the YYYY-MM-DD information current in p, determine if there
 ** is day-of-month overflow and set nFloor to the number of days that
@@ -309,24 +324,12 @@ static void computeJD(DateTime *p){
 ** date back to the end of the month.
 */
 static void computeFloor(DateTime *p){
+  int mxD;         /* Maximum day number for the current month */
   assert( p->validYMD || p->isError );
-  assert( p->D>=0 && p->D<=31 );
+  assert( p->D>=0 && p->D<=32 );
   assert( p->M>=0 && p->M<=12 );
-  if( p->validHMS && p->h==24 ){
-    p->h = 0;
-    p->D++;
-  }
-  if( p->D<=28 ){
-    p->nFloor = 0;
-  }else if( (1<<p->M) & 0x15aa ){
-    p->nFloor = 0;
-  }else if( p->M!=2 ){
-    p->nFloor = (p->D==31);
-  }else if( p->Y%4!=0 || (p->Y%100==0 && p->Y%400!=0) ){
-    p->nFloor = p->D - 28;
-  }else{
-    p->nFloor = p->D - 29;
-  }
+  mxD = daysOfMonth(p->Y, p->M);
+  p->nFloor = p->D>mxD ? p->D - mxD : 0;
 }
 
 /*
@@ -356,7 +359,19 @@ static int parseYyyyMmDd(const char *zDate, DateTime *p){
   zDate += 10;
   while( sqlite3Isspace(*zDate) || 'T'==*(u8*)zDate ){ zDate++; }
   if( parseHhMmSs(zDate, p)==0 ){
-    /* We got the time */
+    if( p->h==24 ){
+      int mxD = daysOfMonth(Y,M);
+      p->h = 0;
+      D++;
+      if( D>mxD ){
+        D -= mxD;
+        M++;
+        if( M>12 ){
+          M = 1;
+          Y++;
+        }
+      }
+    }
   }else if( *zDate==0 ){
     p->validHMS = 0;
   }else{

test/date.test

@@ -760,6 +760,11 @@ datetest 23.13 {strftime('%d/%w/%U/%W','2000-01-01 24:00:00')} {02/0/01/00}
 datetest 23.14 {datetime('24:01')} {NULL}
 datetest 23.15 {datetime('24:00:01')} {NULL}
 datetest 23.16 {datetime('24:00:00.001')} {NULL}
-
+datetest 23.17 {datetime('2024-01-31 24:00:00')} {2024-02-01 00:00:00}
+datetest 23.18 {datetime('2024-02-28 24:00:00')} {2024-02-29 00:00:00}
+datetest 23.19 {datetime('2024-02-29 24:00:00')} {2024-03-01 00:00:00}
+datetest 23.20 {datetime('2025-02-28 24:00:00')} {2025-03-01 00:00:00}
+datetest 23.21 {datetime('2024-04-30 24:00:00')} {2024-05-01 00:00:00}
+datetest 23.22 {datetime('2024-12-31 24:00:00')} {2025-01-01 00:00:00}
 
 finish_test