diff options
Diffstat (limited to 'src/backend/regex/regc_color.c')
| -rw-r--r-- | src/backend/regex/regc_color.c | 18 |
1 files changed, 17 insertions, 1 deletions
diff --git a/src/backend/regex/regc_color.c b/src/backend/regex/regc_color.c index 30bda0e5ad0..8ae788f5195 100644 --- a/src/backend/regex/regc_color.c +++ b/src/backend/regex/regc_color.c @@ -1075,9 +1075,19 @@ colorcomplement(struct nfa *nfa, assert(of != from); - /* A RAINBOW arc matches all colors, making the complement empty */ + /* + * A RAINBOW arc matches all colors, making the complement empty. But we + * can't just return without making any arcs, because that would leave the + * NFA disconnected which would break any future delsub(). Instead, make + * a CANTMATCH arc. Also set the HASCANTMATCH flag so we know we need to + * clean that up at the start of NFA optimization. + */ if (findarc(of, PLAIN, RAINBOW) != NULL) + { + newarc(nfa, CANTMATCH, 0, from, to); + nfa->flags |= HASCANTMATCH; return; + } /* Otherwise, transiently mark the colors that appear in of's out-arcs */ for (a = of->outs; a != NULL; a = a->outchain) @@ -1089,6 +1099,12 @@ colorcomplement(struct nfa *nfa, assert(!UNUSEDCOLOR(cd)); cd->flags |= COLMARK; } + + /* + * There's no syntax for re-complementing a color set, so we cannot + * see CANTMATCH arcs here. + */ + assert(a->type != CANTMATCH); } /* Scan colors, clear transient marks, add arcs for unmarked colors */ |