[gnumeric] StyleCondition: fix crash related to recalc of cell.

[Morten Welinder <mortenw src gnome org>]

commit 8a79de52344ea2641ce9071bd052a780c5409687
Author: Morten Welinder <terra gnome org>
Date:   Sat Oct 13 09:23:30 2018 -0400

    StyleCondition: fix crash related to recalc of cell.
    
    When a cell value is being used to determine style, make sure recalc doesn't
    change the value underneath us.
    
    Additionally, order recalc so cells precede style conditions.

 ChangeLog              | 8 ++++++++
 NEWS                   | 1 +
 src/dependent.c        | 9 +++++++++
 src/style-conditions.c | 9 +++++++--
 4 files changed, 25 insertions(+), 2 deletions(-)
---
diff --git a/ChangeLog b/ChangeLog
index afaba788d..5c3e473e5 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2018-10-13  Morten Welinder  <terra gnome org>
+
+       * src/dependent.c (workbook_recalc): Evaluate cells before other
+       deps.
+
+       * src/style-conditions.c (gnm_style_conditions_eval): Copy the
+       cell value; it may change due to recalc.
+
 2018-10-04  Morten Welinder  <terra gnome org>
 
        * src/sheet-filter.c (gnm_sheet_filter_insdel_colrow): Shorten
diff --git a/NEWS b/NEWS
index 5c90f9e85..cc6c3152d 100644
--- a/NEWS
+++ b/NEWS
@@ -6,6 +6,7 @@ Morten:
        * Fix problem reading really old xls format.
        * Fix sheet filter problem.  [#359]
        * New NT_RADICAL function.
+       * Fix conditional style crash.
 
 --------------------------------------------------------------------------
 Gnumeric 1.12.43
diff --git a/src/dependent.c b/src/dependent.c
index 217e6c08a..f19486e2f 100644
--- a/src/dependent.c
+++ b/src/dependent.c
@@ -2865,6 +2865,15 @@ workbook_recalc (Workbook *wb)
 
        gnm_app_recalc_start ();
 
+       // Do a pass computing only cells; this allows style deps to see
+       // updated values as needed.
+       WORKBOOK_FOREACH_DEPENDENT (wb, dep, {
+               if (dependent_is_cell (dep) && dependent_needs_recalc (dep)) {
+                       redraw = TRUE;
+                       dependent_eval (dep);
+               }
+       });
+
        WORKBOOK_FOREACH_DEPENDENT (wb, dep, {
                if (dependent_needs_recalc (dep)) {
                        redraw = TRUE;
diff --git a/src/style-conditions.c b/src/style-conditions.c
index 9f8ec167c..0769bb18c 100644
--- a/src/style-conditions.c
+++ b/src/style-conditions.c
@@ -978,12 +978,15 @@ gnm_style_conditions_eval (GnmStyleConditions const *sc, GnmEvalPos const *ep)
 {
        unsigned i;
        GPtrArray const *conds;
-       GnmCell const *cell = sheet_cell_get (ep->sheet, ep->eval.col, ep->eval.row);
-       GnmValue const *cv = cell ? cell->value : NULL;
+       GnmCell *cell;
+       GnmValue *cv;
 
        g_return_val_if_fail (sc != NULL, -1);
        g_return_val_if_fail (sc->conditions != NULL, -1);
 
+       cell = sheet_cell_get (ep->sheet, ep->eval.col, ep->eval.row);
+       cv = value_dup (cell->value);
+
        conds = sc->conditions;
 
        if (debug_style_conds ()) {
@@ -1003,6 +1006,7 @@ gnm_style_conditions_eval (GnmStyleConditions const *sc, GnmEvalPos const *ep)
                if (use_this) {
                        if (debug_style_conds ())
                                g_printerr ("  Using clause %d\n", i);
+                       value_release (cv);
                        return i;
                }
        }
@@ -1010,5 +1014,6 @@ gnm_style_conditions_eval (GnmStyleConditions const *sc, GnmEvalPos const *ep)
        if (debug_style_conds ())
                g_printerr ("  No matching clauses\n");
 
+       value_release (cv);
        return -1;
 }