Further cleanup of ts_headline code.

Suppress a probably-meaningless uninitialized-variable warning
(induced by my previous patch, I'm sorry to say).

Improve mark_hl_fragments()'s test for overlapping cover strings:
it failed to consider the possibility that the current string is
strictly within another one.  That's unlikely given the preceding
splitting into MaxWords fragments, but I don't think it's impossible.

Discussion: https://postgr.es/m/16345-2e0cf5cddbdcd3b4@postgresql.org

diff --git a/src/backend/tsearch/wparser_def.c b/src/backend/tsearch/wparser_def.c
index e5c4d7cb04911a87cb834f82c453ecafb5f8b199..48e55e141a4115945865e8002b38c77403e9eeee 100644 (file)
--- a/src/backend/tsearch/wparser_def.c
+++ b/src/backend/tsearch/wparser_def.c
@@ -2337,22 +2337,24 @@ mark_hl_fragments(HeadlineParsedText *prs, TSQuery query, bool highlightall,
            /* Mark the chosen fragments (covers) */
            mark_fragment(prs, highlightall, startpos, endpos);
            num_f++;
-           /* exclude overlapping covers */
+           /* Exclude covers overlapping this one from future consideration */
            for (i = 0; i < numcovers; i++)
            {
                if (i != minI &&
-                   ((covers[i].startpos >= covers[minI].startpos &&
-                     covers[i].startpos <= covers[minI].endpos) ||
-                    (covers[i].endpos >= covers[minI].startpos &&
-                     covers[i].endpos <= covers[minI].endpos)))
+                   ((covers[i].startpos >= startpos &&
+                     covers[i].startpos <= endpos) ||
+                    (covers[i].endpos >= startpos &&
+                     covers[i].endpos <= endpos) ||
+                    (covers[i].startpos < startpos &&
+                     covers[i].endpos > endpos)))
                    covers[i].excluded = true;
            }
        }
        else
-           break;
+           break;              /* no selectable covers remain */
    }
 
-   /* show at least min_words if we have not marked anything */
+   /* show the first min_words words if we have not marked anything */
    if (num_f <= 0)
    {
        startpos = endpos = curlen = 0;
@@ -2510,6 +2512,7 @@ mark_hl_words(HeadlineParsedText *prs, TSQuery query, bool highlightall,
        if (bestlen < 0)
        {
            curlen = 0;
+           pose = 0;
            for (i = 0; i < prs->curwords && curlen < min_words; i++)
            {
                if (!NONWORDTOKEN(prs->words[i].type))