Clear the cache of triggers used to implement CASCADE foreign key constraints

whenever the schema changes.  Fix for the problem identified by
[forum:/forumpost/2831335356|forum post 2831335356].

FossilOrigin-Name: 4f1313c67f8c3025ed15793e370617d14e950c13217f179bfb01f8f48fbbead9

manifest

@@ -1,5 +1,5 @@
-C Earlier\sdetection\sof\scorruption\sin\ssqlite3BtreeDelete().\s\sFix\sfor\nthe\sassertion\sfault\sreported\sby\n[forum:/forumpost/9d78389221|forum\spost\s9d78389221].
-D 2022-01-02T17:46:49.075
+C Clear\sthe\scache\sof\striggers\sused\sto\simplement\sCASCADE\sforeign\skey\sconstraints\nwhenever\sthe\sschema\schanges.\s\sFix\sfor\sthe\sproblem\sidentified\sby\n[forum:/forumpost/2831335356|forum\spost\s2831335356].
+D 2022-01-02T18:10:48.363
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -505,7 +505,7 @@ F src/dbstat.c 861e08690fcb0f2ee1165eff0060ea8d4f3e2ea10f80dab7d32ad70443a6ff2d
 F src/delete.c 0c151975fa99560767d7747f9b60543d0093d9f8b89f13d2d6058e9c83ad19e7
 F src/expr.c 827179c78d2ca7cc318392811de8151c60eacf7ce804b13e61bb7ef38f954846
 F src/fault.c 460f3e55994363812d9d60844b2a6de88826e007
-F src/fkey.c 187b67af20c5795953a592832c5d985e4313fe503ebd8f95e3e9e9ad5a730bb5
+F src/fkey.c 5b73f7a7c00f06017531a5bd258cbc2c7a294e55a7f84a729fe27aa525242560
 F src/func.c 1cfb09d7ffca81238eccefdb0293e1f5b7cfebbd1816dfad5ec6024742a7496b
 F src/global.c 1f56aead86e8a18c4415638f5e6c4d0a0550427f4b3f5d065ba5164cc09c22e8
 F src/hash.c 8d7dda241d0ebdafb6ffdeda3149a412d7df75102cecfc1021c98d6219823b19
@@ -556,7 +556,7 @@ F src/shell.c.in 1458b700144c8326fda2514aaddeda49d6f01f1d1ccf7b9b696c53a3535a119
 F src/sqlite.h.in 5cd209ac7dc4180f0e19292846f40440b8488015849ca0110c70b906b57d68f0
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
 F src/sqlite3ext.h 8ff2fd2c166150b2e48639f5e506fb44e29f1a3f65031710b9e89d1c126ac839
-F src/sqliteInt.h b64ef54425000424f56525974fabbe5f59e444c9bd4a974395eb89f4c7e4628b
+F src/sqliteInt.h 4bf21edf5c330299d1b7399d604da1787001725dbb1c675fe0989ceb1ee8043f
 F src/sqliteLimit.h d7323ffea5208c6af2734574bae933ca8ed2ab728083caa117c9738581a31657
 F src/status.c 4b8bc2a6905163a38b739854a35b826c737333fab5b1f8e03fa7eb9a4799c4c1
 F src/table.c 0f141b58a16de7e2fbe81c308379e7279f4c6b50eb08efeec5892794a0ba30d1
@@ -623,7 +623,7 @@ F src/upsert.c 8789047a8f0a601ea42fa0256d1ba3190c13746b6ba940fe2d25643a7e991937
 F src/utf.c ee39565f0843775cc2c81135751ddd93eceb91a673ea2c57f61c76f288b041a0
 F src/util.c 30df8356e231dad33be10bb27897655002668343280004ba28c734489414a167
 F src/vacuum.c 6c38ddc52f0619865c91dae9c441d4d48bf3040d7dc1bc5b22da1e45547ed0b3
-F src/vdbe.c e98f1baf54a00db2c4669dbd04f8bbc89b5909a5b43e76fbbbf1a97007adba2b
+F src/vdbe.c 84cc51edc36f773a97433c0a1388833557806f56562b6a2cb9fefeadc5e236b0
 F src/vdbe.h 25dabb25c7e157b84e59260cfb5b466c3ac103ede9f36f4db371332c47601abe
 F src/vdbeInt.h 31fbabdc1ed61d9695337dfe5269ea94e1cf615c17f5cafeaa1bb01066820bab
 F src/vdbeapi.c 22c79072ae7d8a01e9bcae8ba16e918d60d202eaa9553b5fda38f99f7464d99a
@@ -1935,9 +1935,9 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 25beca31cf3dbad0e78085c5ceed797a461cfaddc2d41fb7a093aa27098e50d5
-Q +13e9ff9e84a114374b49986484dbee05953a496f3017dd5089fba6f495a17c40
-R 730490404cdcadd8b3d80c14383c2b6c
+P eb07219965721e0a2017d0462747b07178c23f51e3333036e0cb8f5b4751f404
+Q +5232c9777fe4fb13e1ecfe5b5d644e2c45d0514f95884dbed49a03fb9b67304c
+R c7b1ef8a68b04d531afec49469052d40
 U drh
-Z a4ee511e0c37c9dc7a70f5bb4a6e22dd
+Z e0164e9906d72f9b8fdce406798e46c9
 # Remove this line to create a well-formed Fossil manifest.

manifest.uuid

@@ -1 +1 @@
-eb07219965721e0a2017d0462747b07178c23f51e3333036e0cb8f5b4751f404
+4f1313c67f8c3025ed15793e370617d14e950c13217f179bfb01f8f48fbbead9

src/fkey.c

@@ -702,6 +702,25 @@ static void fkTriggerDelete(sqlite3 *dbMem, Trigger *p){
   }
 }
 
+/*
+** Clear the apTrigger[] cache of CASCADE triggers for all foreign keys
+** in a particular database.  This needs to happen when the schema
+** changes.
+*/
+void sqlite3FkClearTriggerCache(sqlite3 *db, int iDb){
+  HashElem *k;
+  Hash *pHash = &db->aDb[iDb].pSchema->tblHash;
+  for(k=sqliteHashFirst(pHash); k; k=sqliteHashNext(k)){
+    Table *pTab = sqliteHashData(k);
+    FKey *pFKey;
+    if( !IsOrdinaryTable(pTab) ) continue;
+    for(pFKey=pTab->u.tab.pFKey; pFKey; pFKey=pFKey->pNextFrom){
+      fkTriggerDelete(db, pFKey->apTrigger[0]); pFKey->apTrigger[0] = 0;
+      fkTriggerDelete(db, pFKey->apTrigger[1]); pFKey->apTrigger[1] = 0;
+    }
+  }
+}
+
 /*
 ** This function is called to generate code that runs when table pTab is
 ** being dropped from the database. The SrcList passed as the second argument

src/sqliteInt.h

@@ -5145,6 +5145,7 @@ const char *sqlite3JournalModename(int);
   int sqlite3FkRequired(Parse*, Table*, int*, int);
   u32 sqlite3FkOldmask(Parse*, Table*);
   FKey *sqlite3FkReferences(Table *);
+  void sqlite3FkClearTriggerCache(sqlite3*,int);
 #else
   #define sqlite3FkActions(a,b,c,d,e,f)
   #define sqlite3FkCheck(a,b,c,d,e,f)
@@ -5152,6 +5153,7 @@ const char *sqlite3JournalModename(int);
   #define sqlite3FkOldmask(a,b)         0
   #define sqlite3FkRequired(a,b,c,d)    0
   #define sqlite3FkReferences(a)        0
+  #define sqlite3FkClearTriggerCache(a,b)
 #endif
 #ifndef SQLITE_OMIT_FOREIGN_KEY
   void sqlite3FkDelete(sqlite3 *, Table*);

src/vdbe.c

@@ -3813,6 +3813,7 @@ case OP_SetCookie: {
     /* When the schema cookie changes, record the new cookie internally */
     pDb->pSchema->schema_cookie = pOp->p3 - pOp->p5;
     db->mDbFlags |= DBFLAG_SchemaChange;
+    sqlite3FkClearTriggerCache(db, pOp->p1);
   }else if( pOp->p2==BTREE_FILE_FORMAT ){
     /* Record changes in the file format */
     pDb->pSchema->file_format = pOp->p3;