Silently ignore redundant ON CONFLICT clauses in an UPSERT. Only the first

ON CONFLICT for each index is active.  Do not issue an error, since that might
break legacy queries.  But ignore the redundant ON CONFLICT clauses to prevent
problems such as described in [forum:/forumpost/919c6579c8|forum post 919c6579c8].

FossilOrigin-Name: d0ea6b6ba64dba9d68c2b391ccf1171ea96fcdd7409dafdb2b697accb00246b8

6 files changed, 73 insertions, 17 deletions

diff --git a/manifest b/manifest
index 91661718c..e75a8d5b8 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Omit\ssome\sextra\stests\sfor\sthe\sintck\sextension\sin\sOMIT_VIRTUAL_TABLE\sor\sOMIT_PRAGMA\sbuilds.
-D 2024-03-08T13:49:43.243
+C Silently\signore\sredundant\sON\sCONFLICT\sclauses\sin\san\sUPSERT.\s\sOnly\sthe\sfirst\nON\sCONFLICT\sfor\seach\sindex\sis\sactive.\s\sDo\snot\sissue\san\serror,\ssince\sthat\smight\nbreak\slegacy\squeries.\s\sBut\signore\sthe\sredundant\sON\sCONFLICT\sclauses\sto\sprevent\nproblems\ssuch\sas\sdescribed\sin\s[forum:/forumpost/919c6579c8|forum\spost\s919c6579c8].
+D 2024-03-08T14:01:48.797
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -709,7 +709,7 @@ F src/hash.c 9ee4269fb1d6632a6fecfb9479c93a1f29271bddbbaf215dd60420bcb80c7220
 F src/hash.h 3340ab6e1d13e725571d7cee6d3e3135f0779a7d8e76a9ce0a85971fa3953c51
 F src/hwtime.h f9c2dfb84dce7acf95ce6d289e46f5f9d3d1afd328e53da8f8e9008e3b3caae6
 F src/in-operator.md 10cd8f4bcd225a32518407c2fb2484089112fd71
-F src/insert.c 3f0a94082d978bbdd33c38fefea15346c6c6bffb70bc645a71dc0f1f87dd3276
+F src/insert.c eb33ea46dcab93e90f112fced343aaf41f59cbd2e951d5066f1f9302be1c2f34
 F src/json.c e2e40760d6689134c3e2ece38c6a496b34ff5e2661a8f238444a119af666fdce
 F src/legacy.c d7874bc885906868cd51e6c2156698f2754f02d9eee1bae2d687323c3ca8e5aa
 F src/loadext.c 7432c944ff197046d67a1207790a1b13eec4548c85a9457eb0896bb3641dfb36
@@ -755,7 +755,7 @@ F src/shell.c.in 78bbd861cd0128aed67c0136561572ebcf11649be6cea86bee8491576d5958d
 F src/sqlite.h.in 19a2db3995a699bd7f6dfb423856242bfceb7ec849a93c91d241d19fc28d9f0f
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
 F src/sqlite3ext.h 3f046c04ea3595d6bfda99b781926b17e672fd6d27da2ba6d8d8fc39981dcb54
-F src/sqliteInt.h 58b7295a748ca5ed9e211510205b4a66a24c68f864225b81e19d4cf6038b40a1
+F src/sqliteInt.h 06d757ee6cd22f59593e51a7066327a0690a6cb66dad4f0077ee3297228f5401
 F src/sqliteLimit.h 6878ab64bdeb8c24a1d762d45635e34b96da21132179023338c93f820eee6728
 F src/status.c cb11f8589a6912af2da3bb1ec509a94dd8ef27df4d4c1a97e0bcf2309ece972b
 F src/table.c 0f141b58a16de7e2fbe81c308379e7279f4c6b50eb08efeec5892794a0ba30d1
@@ -816,7 +816,7 @@ F src/tokenize.c 3f703cacdab728d7741e5a6ac242006d74fe1c2754d4f03ed889d7253259bd6
 F src/treeview.c c6fc972683fd00f975d8b32a81c1f25d2fb7d4035366bf45c9f5622d3ccd70ee
 F src/trigger.c 0905b96b04bb6658509f711a8207287f1315cdbc3df1a1b13ba6483c8e341c81
 F src/update.c 6904814dd62a7a93bbb86d9f1419c7f134a9119582645854ab02b36b676d9f92
-F src/upsert.c fa125a8d3410ce9a97b02cb50f7ae68a2476c405c76aa692d3acf6b8586e9242
+F src/upsert.c 2e60567a0e9e8520c18671b30712a88dc73534474304af94f32bb5f3ef65ac65
 F src/utf.c f23165685a67b4caf8ec08fb274cb3f319103decfb2a980b7cfd55d18dfa855e
 F src/util.c f27a17e6e43fa362abea4db507a1c409f0adc8048ecf4c6479e8d162158ed529
 F src/vacuum.c 604fcdaebe76f3497c855afcbf91b8fa5046b32de3045bab89cc008d68e40104
@@ -1907,7 +1907,7 @@ F test/upsert1.test a512e2f884d3a36159fce2e45108c236f78ae38e35bda55f4050db580ceb
 F test/upsert2.test 720e94d09f7362a282bc69b3c6b83d51daeaaf0440eb4920a08b86518b8c7496
 F test/upsert3.test 88d7d590a1948a9cb6eac1b54b0642f67a9f35a1fc0f19b200e97d5d39e3179c
 F test/upsert4.test 25d2a1da92f149331ae0c51ca6e3eee78189577585eab92de149900d62994fa5
-F test/upsert5.test fff0dcfce73c649204543088d8e5bde01172676063ec9b8f8fc7f195abc386fe
+F test/upsert5.test 9953b180d02d1369cdbb6c73c900834e5fef8cb78e98e07511c8762ec21cc176
 F test/upsertfault.test f21ca47740841fdb4d61acfa7b17646d773e67724fe8c185b71c018db8a94b35
 F test/uri.test c1abaaaa28e9422d61e5f3f9cbc8ef993ec49fe802f581520731708561d49384
 F test/uri2.test 9d3ba7a53ee167572d53a298ee4a5d38ec4a8fb7
@@ -2177,8 +2177,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P a02551de4c2d7085569ee76f88bfef5da429e40137cc1d1349b4637f88259ad1
-R af066a0422542da1cc5e88fc5055710e
-U dan
-Z b2bec38f4a2e9b652e878f166176c721
+P 29d9eb7d55755604781e507f6ca36c50d62fa8d8589ab932d7cefca94ba24f3e
+R 854945d64d6a5cfe38a3cc1c6a5b5bd3
+U drh
+Z 3c2e932dfbe4dcd203c5f3b4ed97d851
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index d5fb64437..492aebc3b 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-29d9eb7d55755604781e507f6ca36c50d62fa8d8589ab932d7cefca94ba24f3e
\ No newline at end of file
+d0ea6b6ba64dba9d68c2b391ccf1171ea96fcdd7409dafdb2b697accb00246b8
\ No newline at end of file
diff --git a/src/insert.c b/src/insert.c
index 1c31ca233..095298b90 100644
--- a/src/insert.c
+++ b/src/insert.c
@@ -1086,7 +1086,7 @@ void sqlite3Insert(
       pNx->iDataCur = iDataCur;
       pNx->iIdxCur = iIdxCur;
       if( pNx->pUpsertTarget ){
-        if( sqlite3UpsertAnalyzeTarget(pParse, pTabList, pNx) ){
+        if( sqlite3UpsertAnalyzeTarget(pParse, pTabList, pNx, pUpsert) ){
           goto insert_cleanup;
         }
       }
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index f5920748b..91cf17304 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -3476,6 +3476,7 @@ struct Upsert {
   Expr *pUpsertWhere;       /* WHERE clause for the ON CONFLICT UPDATE */
   Upsert *pNextUpsert;      /* Next ON CONFLICT clause in the list */
   u8 isDoUpdate;            /* True for DO UPDATE.  False for DO NOTHING */
+  u8 isDup;                 /* True if 2nd or later with same pUpsertIdx */
   /* Above this point is the parse tree for the ON CONFLICT clauses.
   ** The next group of fields stores intermediate data. */
   void *pToFree;            /* Free memory when deleting the Upsert object */
@@ -5552,7 +5553,7 @@ const char *sqlite3JournalModename(int);
   Upsert *sqlite3UpsertNew(sqlite3*,ExprList*,Expr*,ExprList*,Expr*,Upsert*);
   void sqlite3UpsertDelete(sqlite3*,Upsert*);
   Upsert *sqlite3UpsertDup(sqlite3*,Upsert*);
-  int sqlite3UpsertAnalyzeTarget(Parse*,SrcList*,Upsert*);
+  int sqlite3UpsertAnalyzeTarget(Parse*,SrcList*,Upsert*,Upsert*);
   void sqlite3UpsertDoUpdate(Parse*,Upsert*,Table*,Index*,int);
   Upsert *sqlite3UpsertOfIndex(Upsert*,Index*);
   int sqlite3UpsertNextIsIPK(Upsert*);
diff --git a/src/upsert.c b/src/upsert.c
index be0d0550d..f74d4fabf 100644
--- a/src/upsert.c
+++ b/src/upsert.c
@@ -90,7 +90,8 @@ Upsert *sqlite3UpsertNew(
 int sqlite3UpsertAnalyzeTarget(
   Parse *pParse,     /* The parsing context */
   SrcList *pTabList, /* Table into which we are inserting */
-  Upsert *pUpsert    /* The ON CONFLICT clauses */
+  Upsert *pUpsert,   /* The ON CONFLICT clauses */
+  Upsert *pAll       /* Complete list of all ON CONFLICT clauses */
 ){
   Table *pTab;            /* That table into which we are inserting */
   int rc;                 /* Result code */
@@ -193,6 +194,14 @@ int sqlite3UpsertAnalyzeTarget(
         continue;
       }
       pUpsert->pUpsertIdx = pIdx;
+      if( sqlite3UpsertOfIndex(pAll,pIdx)!=pUpsert ){
+        /* Really this should be an error.  The isDup ON CONFLICT clause will
+        ** never fire.  But this problem was not discovered until three years
+        ** after multi-CONFLICT upsert was added, and so we silently ignore
+        ** the problem to prevent breaking applications that might actually
+        ** have redundant ON CONFLICT clauses. */
+        pUpsert->isDup = 1;
+      }
       break;
     }
     if( pUpsert->pUpsertIdx==0 ){
@@ -219,9 +228,13 @@ int sqlite3UpsertNextIsIPK(Upsert *pUpsert){
   Upsert *pNext;
   if( NEVER(pUpsert==0) ) return 0;
   pNext = pUpsert->pNextUpsert;
-  if( pNext==0 ) return 1;
-  if( pNext->pUpsertTarget==0 ) return 1;
-  if( pNext->pUpsertIdx==0 ) return 1;
+  while( 1 /*exit-by-return*/ ){
+    if( pNext==0 ) return 1;
+    if( pNext->pUpsertTarget==0 ) return 1;
+    if( pNext->pUpsertIdx==0 ) return 1;
+    if( !pNext->isDup ) return 0;
+    pNext = pNext->pNextUpsert;
+  }
   return 0;
 }
 
diff --git a/test/upsert5.test b/test/upsert5.test
index 3161abf15..e56e71d4b 100644
--- a/test/upsert5.test
+++ b/test/upsert5.test
@@ -408,4 +408,46 @@ do_catchsql_test 2.1 {
 
 } {1 {no such table: nosuchtable}}
 
+# 2024-03-08 https://sqlite.org/forum/forumpost/919c6579c8
+# A redundant ON CONFLICT clause in an upsert can lead to
+# index corruption.
+#
+reset_db
+do_execsql_test 3.0 {
+  CREATE TABLE t1(aa INTEGER PRIMARY KEY, bb INT);
+  INSERT INTO t1 VALUES(11,22);
+  CREATE UNIQUE INDEX t1bb ON t1(bb);
+  REPLACE INTO t1 VALUES(11,33)
+    ON CONFLICT(bb) DO UPDATE SET aa = 44
+    ON CONFLICT(bb) DO UPDATE SET aa = 44;
+  PRAGMA integrity_check;
+} {ok}
+do_execsql_test 3.1 {
+  SELECT * FROM t1 NOT INDEXED;
+} {11 33}
+do_execsql_test 3.2 {
+  SELECT * FROM t1 INDEXED BY t1bb;
+} {11 33}
+do_execsql_test 3.3 {
+  DROP TABLE t1;
+  CREATE TABLE t1(aa INTEGER PRIMARY KEY, bb INT, cc INT);
+  INSERT INTO t1 VALUES(10,21,32),(11,22,33),(12,23,34);
+  CREATE UNIQUE INDEX t1bb ON t1(bb);
+  CREATE UNIQUE INDEX t1cc ON t1(cc);
+  REPLACE INTO t1 VALUES(11,44,55)
+    ON CONFLICT(bb) DO UPDATE SET aa = 99
+    ON CONFLICT(cc) DO UPDATE SET aa = 99
+    ON CONFLICT(bb) DO UPDATE SET aa = 99;
+  PRAGMA integrity_check;
+} {ok}
+do_execsql_test 3.4 {
+  SELECT * FROM t1 NOT INDEXED ORDER BY +aa;
+} {10 21 32 11 44 55 12 23 34}
+do_execsql_test 3.5 {
+  SELECT * FROM t1 INDEXED BY t1bb ORDER BY +aa;
+} {10 21 32 11 44 55 12 23 34}
+do_execsql_test 3.6 {
+  SELECT * FROM t1 INDEXED BY t1cc ORDER BY +aa;
+} {10 21 32 11 44 55 12 23 34}
+
 finish_test