From 7e7fd73b25f83b6aac246a79990e0f5ff3019e7c Mon Sep 17 00:00:00 2001
From: drh <drh@noemail.net>
Date: Tue, 22 Oct 2019 13:59:23 +0000
Subject: [PATCH] In UPDATE processing, include generated columns in the set of
 columns being updated if and only if their generator expressions reference
 some other column that is being updated.

FossilOrigin-Name: d38176e93a628e03f1bd8b689fbc4152a1495388da917c2d89cefed04353d2d6
---
 manifest      | 14 +++++++-------
 manifest.uuid |  2 +-
 src/build.c   | 10 ++++++++--
 src/update.c  | 28 ++++++++++++++++++++++++++++
 4 files changed, 44 insertions(+), 10 deletions(-)

diff --git a/manifest b/manifest
index 939aaa0a07..723757465a 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C New\stestcase()\smacros.\s\sFix\sa\sproblem\swith\sINSERT\swhen\sthe\sIPK\sis\sto\sthe\nright\sof\sgenerated\scolumns.
-D 2019-10-22T13:01:24.252
+C In\sUPDATE\sprocessing,\sinclude\sgenerated\scolumns\sin\sthe\sset\sof\scolumns\sbeing\nupdated\sif\sand\sonly\sif\stheir\sgenerator\sexpressions\sreference\ssome\sother\ncolumn\sthat\sis\sbeing\supdated.
+D 2019-10-22T13:59:23.530
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -469,7 +469,7 @@ F src/btmutex.c 8acc2f464ee76324bf13310df5692a262b801808984c1b79defb2503bbafadb6
 F src/btree.c a8a9c2ce62bdf54c8cf9795143d7cb10b7473a1230a0572f702d061ffcceefe5
 F src/btree.h f27a33c49280209a93385e218306c4ee5f46ba8d7649d2f81a7166b282232484
 F src/btreeInt.h 91806f01fd1145a9a86ba3042f25c38d8faf6002701bf5e780742cf88bcff437
-F src/build.c acf54f35164aff7f0b06b82aae357e76e08b74e4c904bafd96643d4e155f34f8
+F src/build.c 27471914e516d7d0f21d16c74f9e84bdfda1160bfd11e33a74cbe1d5a08dbc9e
 F src/callback.c 88615dfc0a82167b65b452b4b305dbf86be77200b3343c6ffc6d03e92a01d181
 F src/complete.c a3634ab1e687055cd002e11b8f43eb75c17da23e
 F src/ctime.c 1b0724e66f95f33b160b1af85caaf9cceb325d22abf39bd24df4f54a73982251
@@ -592,7 +592,7 @@ F src/threads.c 4ae07fa022a3dc7c5beb373cf744a85d3c5c6c3c
 F src/tokenize.c 7b17f6e2f20f6cbcb0b215025a86b7457c38451fc7622f705e553d7a488c572d
 F src/treeview.c fddeb413159c3eeeaea3f496172f121cf3695606c461dc4e6dcee51417952df5
 F src/trigger.c 845ccc08f60716c58aa28fe6470385c18ef8c4e1d88c93dcf449bc13d464eb2e
-F src/update.c 287146d2ce191228f0afaa34ffcaaaa196e2c2e2664008914e925dea6a64403e
+F src/update.c 3a5e1fa8e29413ee633f049bf9f0e1eb33a03a53cb55b6ea290120b324fbf46e
 F src/upsert.c b445315c8958d8f17ec3297d06842e61dacaad0633ccaec1e4e160de7e562212
 F src/utf.c 2f0fac345c7660d5c5bd3df9e9d8d33d4c27f366bcfb09e07443064d751a0507
 F src/util.c 10d910e04a4f3842042485e0df01a484f57f912c10b60b3a09ccddd5019bd138
@@ -1847,7 +1847,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P ba123b8c201053d8f9387de38f3513b06f7721b28d79fab8489f96d336105117
-R c1cc6d4a971f76b9e92c16fa65923060
+P 412799fc5527aaca987e4e04b8a4f774dcdb70fb80e3a126dc3a26d48a66935c
+R d35fda238d05afc96b47f324f26c5dfe
 U drh
-Z 35d27d665bc3fbce0f6de471df281b5a
+Z 00de734fe264a9e4a103cd3816a6d374
diff --git a/manifest.uuid b/manifest.uuid
index 0a61aea937..e9177c9e9c 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-412799fc5527aaca987e4e04b8a4f774dcdb70fb80e3a126dc3a26d48a66935c
\ No newline at end of file
+d38176e93a628e03f1bd8b689fbc4152a1495388da917c2d89cefed04353d2d6
\ No newline at end of file
diff --git a/src/build.c b/src/build.c
index 2ba9398226..efdcb59b1e 100644
--- a/src/build.c
+++ b/src/build.c
@@ -1405,6 +1405,12 @@ void sqlite3AddDefaultValue(
     if( !sqlite3ExprIsConstantOrFunction(pExpr, db->init.busy) ){
       sqlite3ErrorMsg(pParse, "default value of column [%s] is not constant",
           pCol->zName);
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+    }else if( pCol->colFlags & COLFLAG_GENERATED ){
+      testcase( pCol->colflags & COLFLAG_VIRTUAL );
+      testcase( pCol->colflags & COLFLAG_STORED );
+      sqlite3ErrorMsg(pParse, "cannot use DEFAULT on a generated column");
+#endif
     }else{
       /* A copy of pExpr is used instead of the original, as pExpr contains
       ** tokens that point to volatile memory.
@@ -1633,14 +1639,14 @@ void sqlite3AddGenerated(Parse *pParse, Expr *pExpr, Token *pType){
   goto generated_done;
 
 generated_error:
-  sqlite3ErrorMsg(pParse, "incorrect GENERATED ALWAYS AS on column \"%s\"",
+  sqlite3ErrorMsg(pParse, "error in generated column \"%s\"",
                   pCol->zName);
 generated_done:
   sqlite3ExprDelete(pParse->db, pExpr);
 #else
   /* Throw and error for the GENERATED ALWAYS AS clause if the
   ** SQLITE_OMIT_GENERATED_COLUMNS compile-time option is used. */
-  sqlite3ErrorMsg(pParse, "GENERATED ALWAYS AS not supported");
+  sqlite3ErrorMsg(pParse, "generated columns not supported");
   sqlite3ExprDelete(pParse->db, pExpr);
 #endif
 }
diff --git a/src/update.c b/src/update.c
index 48413a0df9..d690b69f95 100644
--- a/src/update.c
+++ b/src/update.c
@@ -356,6 +356,33 @@ void sqlite3Update(
   assert( chngPk==0 || chngPk==1 );
   chngKey = chngRowid + chngPk;
 
+#ifndef SQLITE_OMIT_GENERATED_COLUMNS
+  /* Mark generated columns as changing if their generator expressions
+  ** reference any changing column.  The actual aXRef[] value for 
+  ** generated expressions is not used, other than to check to see that it
+  ** is non-negative, so the value of aXRef[] for generated columns can be
+  ** set to any non-negative number.  We use 99999 so that the value is
+  ** obvious when looking at aXRef[] in a symbolic debugger. 
+  */
+  if( pTab->tabFlags & TF_HasGenerated ){
+    int bProgress;
+    testcase( pTab->tabFlags & TF_HasVirtual );
+    testcase( pTab->tabFlags & TF_HasStored );
+    do{
+      bProgress = 0;
+      for(i=0; i<pTab->nCol; i++){
+        if( aXRef[i]>=0 ) continue;
+        if( (pTab->aCol[i].colFlags & COLFLAG_GENERATED)==0 ) continue;
+        if( sqlite3ExprReferencesUpdatedColumn(pTab->aCol[i].pDflt,
+                                               aXRef, chngRowid) ){
+          aXRef[i] = 99999;
+          bProgress = 1;
+        }
+      }
+    }while( bProgress );
+  }
+#endif
+
   /* The SET expressions are not actually used inside the WHERE loop.  
   ** So reset the colUsed mask. Unless this is a virtual table. In that
   ** case, set all bits of the colUsed mask (to ensure that the virtual
@@ -952,6 +979,7 @@ static void updateVirtualTable(
 
   /* Populate the argument registers. */
   for(i=0; i<pTab->nCol; i++){
+    assert( (pTab->aCol[i].colFlags & COLFLAG_GENERATED)==0 );
     if( aXRef[i]>=0 ){
       sqlite3ExprCode(pParse, pChanges->a[aXRef[i]].pExpr, regArg+2+i);
     }else{