Fix infinite-loop risk in fixempties() stage of regex compilation.
Tom Lane <tgl@sss.pgh.pa.us>
Fix infinite-loop risk in fixempties() stage of regex compilation. The previous coding of this function could get into situations where it would never terminate, because successive passes would re-add EMPTY arcs that had been removed by the previous pass. Rewrite the function completely using a new algorithm that is guaranteed to terminate, and also seems to be usually faster than the old one. Per Tcl bugs 3604074 and 3606683. Tom Lane and Don Porter
Files
| Path | Change | +/− |
|---|---|---|
| src/backend/regex/regc_nfa.c | modified | +245 −69 |
| src/backend/regex/regcomp.c | modified | +8 −4 |
| src/test/regress/expected/regex.out | modified | +20 −0 |
| src/test/regress/sql/regex.sql | modified | +7 −0 |