[gnumeric] Style: debug improvement.

[Morten Welinder <mortenw src gnome org>]

commit 3fbaa46bea580aa1b30c74a1557916984e45a2dc
Author: Morten Welinder <terra gnome org>
Date:   Sat Jul 11 18:40:54 2020 -0400

    Style: debug improvement.

 src/mstyle.c | 31 ++++++++++++++++++++++++++-----
 1 file changed, 26 insertions(+), 5 deletions(-)
---
diff --git a/src/mstyle.c b/src/mstyle.c
index 0c7eda2f0..8c29fdb5c 100644
--- a/src/mstyle.c
+++ b/src/mstyle.c
@@ -2357,11 +2357,12 @@ gnm_style_link_dependents (GnmStyle *style, GnmRange const *r)
                ? gnm_style_get_conditions (style)
                : NULL;
        if (sc) {
+               GnmParsePos pp;
                GPtrArray const *conds = gnm_style_conditions_details (sc);
                guint ui;
-               if (debug_style_deps)
-                       g_printerr ("Linking %s for %p\n",
-                                   range_as_string (r), style);
+
+               parse_pos_init (&pp, NULL, sheet, r->start.col, r->start.row);
+
                for (ui = 0; conds && ui < conds->len; ui++) {
                        GnmStyleCond const *c = g_ptr_array_index (conds, ui);
                        guint ei;
@@ -2369,9 +2370,29 @@ gnm_style_link_dependents (GnmStyle *style, GnmRange const *r)
                        for (ei = 0; ei < 2; ei++) {
                                GnmExprTop const *texpr =
                                        gnm_style_cond_get_expr (c, ei);
-                               if (!texpr ||
-                                   cond_expr_harmless (texpr->expr))
+                               char *s = NULL;
+                               if (!texpr)
+                                       continue;
+
+                               if (debug_style_deps)
+                                       s = gnm_expr_top_as_string (texpr, &pp,
+                                                                   sheet_get_conventions (sheet));
+
+                               if (cond_expr_harmless (texpr->expr)) {
+                                       if (debug_style_deps) {
+                                               g_printerr ("Not linking %s %d:%d for %p: %s (harmless)\n",
+                                                           range_as_string (r), ui, ei, style, s);
+                                               g_free (s);
+                                       }
                                        continue;
+                               }
+
+                               if (debug_style_deps) {
+                                       g_printerr ("Linking %s %d:%d for %p: %s\n",
+                                                   range_as_string (r), ui, ei, style, s);
+                                       g_free (s);
+                               }
+
                                if (!style->deps)
                                        style->deps = g_ptr_array_new ();
                                gnm_dep_style_dependency