Revert part of the previous diff to fix a regression (another endless loop)

reported by Michael <Stapelberg at Debian> in the Linux md(4) manual.

The reason the colwidth[] array is needed is not that it stores widths
different from those in tbl->cols[].width, but that only part of the
columns participate in the comparisons, i.e. only those intersecting
at least one span the still requires width distribution.

diff --git a/usr.bin/mandoc/out.c b/usr.bin/mandoc/out.c
index 6d73c08..28dcc25 100644 (file)
--- a/usr.bin/mandoc/out.c
+++ b/usr.bin/mandoc/out.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: out.c,v 1.54 2021/09/07 17:05:30 schwarze Exp $ */
+/*     $OpenBSD: out.c,v 1.55 2021/09/28 17:06:17 schwarze Exp $ */
 /*
  * Copyright (c) 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2011, 2014, 2015, 2017, 2018, 2019, 2021
@@ -121,6 +121,7 @@ tblcalc(struct rofftbl *tbl, const struct tbl_span *sp_first,
        const struct tbl_dat    *dp;
        struct roffcol          *col;
        struct tbl_colgroup     *first_group, **gp, *g;
+       size_t                  *colwidth;
        size_t                   ewidth, min1, min2, wanted, width, xwidth;
        int                      done, icol, maxcol, necol, nxcol, quirkcol;
 
@@ -254,8 +255,20 @@ tblcalc(struct rofftbl *tbl, const struct tbl_span *sp_first,
                        gp = &(*gp)->next;
        }
 
+       colwidth = mandoc_reallocarray(NULL, maxcol + 1, sizeof(*colwidth));
        while (first_group != NULL) {
 
+               /*
+                * Rebuild the array of the widths of all columns
+                * participating in spans that require expansion.
+                */
+
+               for (icol = 0; icol <= maxcol; icol++)
+                       colwidth[icol] = SIZE_MAX;
+               for (g = first_group; g != NULL; g = g->next)
+                       for (icol = g->startcol; icol <= g->endcol; icol++)
+                               colwidth[icol] = tbl->cols[icol].width;
+
                /*
                 * Find the smallest and second smallest column width
                 * among the columns which may need expamsion.
@@ -263,7 +276,7 @@ tblcalc(struct rofftbl *tbl, const struct tbl_span *sp_first,
 
                min1 = min2 = SIZE_MAX;
                for (icol = 0; icol <= maxcol; icol++) {
-                       width = tbl->cols[icol].width;
+                       width = colwidth[icol];
                        if (min1 > width) {
                                min2 = min1;
                                min1 = width;
@@ -281,7 +294,7 @@ tblcalc(struct rofftbl *tbl, const struct tbl_span *sp_first,
                for (g = first_group; g != NULL; g = g->next) {
                        necol = 0;
                        for (icol = g->startcol; icol <= g->endcol; icol++)
-                               if (tbl->cols[icol].width == min1)
+                               if (colwidth[icol] == min1)
                                        necol++;
                        if (necol == 0)
                                continue;
@@ -298,7 +311,7 @@ tblcalc(struct rofftbl *tbl, const struct tbl_span *sp_first,
                while ((g = *gp) != NULL) {
                        done = 0;
                        for (icol = g->startcol; icol <= g->endcol; icol++) {
-                               if (tbl->cols[icol].width != min1)
+                               if (colwidth[icol] != min1)
                                        continue;
                                if (g->wanted <= wanted - min1) {
                                        tbl->cols[icol].width += g->wanted;
@@ -315,6 +328,7 @@ tblcalc(struct rofftbl *tbl, const struct tbl_span *sp_first,
                                gp = &(*gp)->next;
                }
        }
+       free(colwidth);
 
        /*
         * Align numbers with text.