Fix another corner-case for the 'start of ...' modifier in the date/time

functions.  Related to ticket [6097cb92745327a1].

FossilOrigin-Name: 8831f4393dda42b3434e7767968caea84bbca2af

manifest

@@ -1,5 +1,5 @@
-C Fix\sa\scase\sintroduced\sby\s[4cd2a967]\swhere\sa\scorrupt\sdatabase\scould\scause\sa\sbuffer\soverwrite.
-D 2017-03-03T20:02:53.439
+C Fix\sanother\scorner-case\sfor\sthe\s'start\sof\s...'\smodifier\sin\sthe\sdate/time\nfunctions.\s\sRelated\sto\sticket\s[6097cb92745327a1].
+D 2017-03-03T20:43:43.649
 F Makefile.in edb6bcdd37748d2b1c3422ff727c748df7ffe918
 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
 F Makefile.msc a89ea37ab5928026001569f056973b9059492fe2
@@ -347,7 +347,7 @@ F src/build.c 51b473eec465f471d607b54e8dbc00751c3f8a1f
 F src/callback.c 2e76147783386374bf01b227f752c81ec872d730
 F src/complete.c a3634ab1e687055cd002e11b8f43eb75c17da23e
 F src/ctime.c a9984df73898c042a5cfc8f9d8e7723d02bc35c9
-F src/date.c bb4db348be17903f4bbf2ef3cb208add874deab9
+F src/date.c 499343d9cd97fb0c13ec299dbd1ff3d787b1cdac
 F src/dbstat.c 19ee7a4e89979d4df8e44cfac7a8f905ec89b77d
 F src/delete.c 0d9d5549d42e79ce4d82ff1db1e6c81e36d2f67c
 F src/expr.c 8a29e9b72d4b642189999c41782cd6c5bc43512f
@@ -638,7 +638,7 @@ F test/csv01.test e0ba3caaa57e4c667a0b45977689fb8082f14348
 F test/ctime.test ff6c38e822459d6ca743c34901caf57740b08b54
 F test/cursorhint.test 7bc346788390475e77a345da2b92270d04d35856
 F test/cursorhint2.test 8457e93d97f665f23f97cdbc8477d16e3480331b
-F test/date.test e6da60d8ec399de43c076425fbe2eecbc90a31a4
+F test/date.test 9b73bbeb1b82d9c1f44dec5cf563bf7da58d2373
 F test/dbfuzz.c 73047c920d6210e5912c87cdffd9a1c281d4252e
 F test/dbselftest.c b2e6cfac59066dbcb7334b66304bb15a5508dd42
 F test/dbstatus.test 73149851b3aff14fc6db478e58f9083a66422cf5
@@ -1561,7 +1561,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 915a9a28783fbb2f4c0794eb4264ce8c0b9d42f7
-R 87fee79fc77f11db6d08a83e962c36d1
-U dan
-Z d96b298a9dab6e01e07206495b42117b
+P 5d0455fece514552ad7f283d56526f53d7c688bd
+R 7ede60c220c81f4f24b446e38f3b85e3
+U drh
+Z 2f7d593b5303445a6b7dc1a2027118f1

manifest.uuid

@@ -1 +1 @@
-5d0455fece514552ad7f283d56526f53d7c688bd
+8831f4393dda42b3434e7767968caea84bbca2af

src/date.c

@@ -743,6 +743,7 @@ static int parseModifier(
       ** or month or year.
       */
       if( sqlite3_strnicmp(z, "start of ", 9)!=0 ) break;
+      if( !p->validJD && !p->validYMD && !p->validHMS ) break;
       z += 9;
       computeYMD(p);
       p->validHMS = 1;

test/date.test

@@ -604,6 +604,8 @@ datetest 17.2 {datetime(2457828)} {2017-03-15 12:00:00}
 datetest 17.3 {datetime(2457828,'start of day')} {2017-03-15 00:00:00}
 datetest 17.4 {datetime(2457828,'start of month')} {2017-03-01 00:00:00}
 datetest 17.5 {datetime(2457828,'start of year')} {2017-01-01 00:00:00}
+datetest 17.6 {datetime(37,'start of year')} NULL
+datetest 17.7 {datetime(38,'start of year')} {-4712-01-01 00:00:00}