Fix .expert name collision bug reported at https://sqlite.org/forum/forumpost/05e6f32984561f57?t=h

FossilOrigin-Name: 4a3f98ad0dd2a8c0370042611a041bed2bd8d9ca82d6706e2db349eb97aaf1f0

ext/expert/expert1.test

@@ -196,7 +196,7 @@ do_setup_rec_test $tn.9.1 {
 } {
   SELECT * FROM "t t" WHERE a=?
 } {
-  CREATE INDEX 't t_idx_00000061' ON 't t'(a);
+  CREATE INDEX "t t_idx_00000061" ON "t t"(a);
   SEARCH t t USING INDEX t t_idx_00000061 (a=?) 
 }
 
@@ -205,7 +205,7 @@ do_setup_rec_test $tn.9.2 {
 } {
   SELECT * FROM "t t" WHERE b BETWEEN ? AND ?
 } {
-  CREATE INDEX 't t_idx_00000062' ON 't t'(b);
+  CREATE INDEX "t t_idx_00000062" ON "t t"(b);
   SEARCH t t USING INDEX t t_idx_00000062 (b>? AND b<?)
 }
 

ext/expert/sqlite3expert.c

@@ -914,6 +914,18 @@ static int idxFindCompatible(
   return 0;
 }
 
+/* Callback for sqlite3_exec() with query with leading count(*) column.
+ * The first argument is expected to be an int*, referent to be incremented
+ * if that leading column is not exactly '0'.
+ */
+static int countNonzeros(void* pCount, int nc,
+                         char* azResults[], char* azColumns[]){
+  if( nc>0 && azResults[0][0]!='0' || azResults[0][1]!=0 ){
+    *((int *)pCount) += 1;
+  }
+  return 0;
+}
+
 static int idxCreateFromCons(
   sqlite3expert *p,
   IdxScan *pScan,
@@ -940,17 +952,40 @@ static int idxCreateFromCons(
     if( rc==SQLITE_OK ){
       /* Hash the list of columns to come up with a name for the index */
       const char *zTable = pScan->pTab->zName;
-      char *zName;                /* Index name */
-      int i;
-      for(i=0; zCols[i]; i++){
-        h += ((h<<3) + zCols[i]);
-      }
-      zName = sqlite3_mprintf("%s_idx_%08x", zTable, h);
-      if( zName==0 ){ 
+      int quoteTable = idxIdentifierRequiresQuotes(zTable);
+      char *zName = 0;          /* Index name */
+      int collisions = 0;
+      do{
+        int i;
+        char *zFind;
+        for(i=0; zCols[i]; i++){
+          h += ((h<<3) + zCols[i]);
+        }
+        sqlite3_free(zName);
+        zName = sqlite3_mprintf("%s_idx_%08x", zTable, h);
+        if( zName==0 ) break;
+        /* Is is unique among table, view and index names? */
+        zFmt = "SELECT count(*) FROM sqlite_schema WHERE name=%Q"
+          " AND type in ('index','table','view')";
+        zFind = sqlite3_mprintf(zFmt, zName);
+        i = 0;
+        rc = sqlite3_exec(dbm, zFind, countNonzeros, &i, 0);
+        assert(rc==SQLITE_OK);
+        sqlite3_free(zFind);
+        if( i==0 ){
+          collisions = 0;
+          break;
+        }
+        ++collisions;
+      }while( collisions<50 && zName!=0 );
+      if( collisions ){
+        /* This return means "Gave up trying to find a unique index name." */
+        rc = SQLITE_BUSY_TIMEOUT;
+      }else if( zName==0 ){
         rc = SQLITE_NOMEM;
       }else{
-        if( idxIdentifierRequiresQuotes(zTable) ){
-          zFmt = "CREATE INDEX '%q' ON %Q(%s)";
+        if( quoteTable ){
+          zFmt = "CREATE INDEX \"%w\" ON \"%w\"(%s)";
         }else{
           zFmt = "CREATE INDEX %s ON %s(%s)";
         }
@@ -959,7 +994,11 @@ static int idxCreateFromCons(
           rc = SQLITE_NOMEM;
         }else{
           rc = sqlite3_exec(dbm, zIdx, 0, 0, p->pzErrmsg);
-          idxHashAdd(&rc, &p->hIdx, zName, zIdx);
+          if( rc!=SQLITE_OK ){
+            rc = SQLITE_BUSY_TIMEOUT;
+          }else{
+            idxHashAdd(&rc, &p->hIdx, zName, zIdx);
+          }
         }
         sqlite3_free(zName);
         sqlite3_free(zIdx);
@@ -1883,6 +1922,10 @@ int sqlite3_expert_analyze(sqlite3expert *p, char **pzErr){
   /* Create candidate indexes within the in-memory database file */
   if( rc==SQLITE_OK ){
     rc = idxCreateCandidates(p);
+  }else if ( rc==SQLITE_BUSY_TIMEOUT ){
+    if( pzErr )
+      *pzErr = sqlite3_mprintf("Cannot find a unique index name to propose.");
+    return rc;
   }
 
   /* Generate the stat1 data */

manifest

@@ -1,5 +1,5 @@
-C Speed\sand\s(slightly)\ssimplify\sshell's\sinput\sline\searly\sprocessing.
-D 2021-09-21T19:19:28.756
+C Fix\s.expert\sname\scollision\sbug\sreported\sat\shttps://sqlite.org/forum/forumpost/05e6f32984561f57?t=h
+D 2021-09-21T20:03:05.965
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -50,8 +50,8 @@ F ext/async/sqlite3async.c 6f247666b495c477628dd19364d279c78ea48cd90c72d9f9b98ad
 F ext/async/sqlite3async.h 46b47c79357b97ad85d20d2795942c0020dc20c532114a49808287f04aa5309a
 F ext/expert/README.md b321c2762bb93c18ea102d5a5f7753a4b8bac646cb392b3b437f633caf2020c3
 F ext/expert/expert.c d548d603a4cc9e61f446cc179c120c6713511c413f82a4a32b1e1e69d3f086a4
-F ext/expert/expert1.test 6703fd74711daf8230240680b0a348d0720e28819b602701adfbd32457fdcddd
-F ext/expert/sqlite3expert.c fdcd3bd969351c4e860a1368a6ab64bc4c94d2d89396805b28853a514d06fd92
+F ext/expert/expert1.test 3c642a4e7bbb14f21ddab595436fb465a4733f47a0fe5b2855e1d5ff900ef08e
+F ext/expert/sqlite3expert.c 396c9003d6fe94b6a82311bfe7c30fa430ec7efd56417bf6b32d11737c1624fb
 F ext/expert/sqlite3expert.h ca81efc2679a92373a13a3e76a6138d0310e32be53d6c3bfaedabd158ea8969b
 F ext/expert/test_expert.c d56c194b769bdc90cf829a14c9ecbc1edca9c850b837a4d0b13be14095c32a72
 F ext/fts1/README.txt 20ac73b006a70bcfd80069bdaf59214b6cf1db5e
@@ -1925,7 +1925,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 2c0e7ae541e9ecb86aa58fa7e7057def8aac1b1af1af1aa80b8bf2d260f9a2f9 577544c5a2f193e00e5ca55b7feae96568198019573b9b0b37e2bf4300d6d524
-R 3f0f5d8f4d6753399cf7fbd70ddb9c72
+P a1c7f7f8e1b46440234be96e813e4c2c28150413dd95dcab5d13b9c80a202edf
+R 4025a996a7ae646cead16f1b9879d649
 U larrybr
-Z da72ab7831c9560c80854036f35fcf46
+Z c2e5ece08cc58eb5c76d74654bc5b60e

manifest.uuid

@@ -1 +1 @@
-a1c7f7f8e1b46440234be96e813e4c2c28150413dd95dcab5d13b9c80a202edf
+4a3f98ad0dd2a8c0370042611a041bed2bd8d9ca82d6706e2db349eb97aaf1f0