[evolution] ECompEditor: Timezone can be reset on component save

[Milan Crha <mcrha src gnome org>]

commit 9bbb9289477c8a61a641b0b67cec367629f1e73a
Author: Milan Crha <mcrha redhat com>
Date:   Thu Feb 10 11:59:36 2022 +0100

    ECompEditor: Timezone can be reset on component save
    
    The libical 3.0.14 contains a change, which unsets non-UTC timezones
    in date/time values. That uncovered a bug in the Evolution code, which
    expects the timezone will be preserved on re-read from the component,
    but it's not always possible. This is corrected by re-setting the timezone
    on the used ICalTime value.

 src/calendar/gui/e-comp-editor-property-part.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)
---
diff --git a/src/calendar/gui/e-comp-editor-property-part.c b/src/calendar/gui/e-comp-editor-property-part.c
index 6bed833b12..6ce699a2e6 100644
--- a/src/calendar/gui/e-comp-editor-property-part.c
+++ b/src/calendar/gui/e-comp-editor-property-part.c
@@ -913,8 +913,15 @@ ecepp_datetime_fill_component (ECompEditorPropertyPart *property_part,
                        g_object_unref (prop);
                }
        } else {
+               ICalTimezone *zone;
+
                value = e_comp_editor_property_part_datetime_get_value (part_datetime);
 
+               zone = value && !i_cal_time_is_null_time (value) ? i_cal_time_get_timezone (value) : NULL;
+
+               if (zone)
+                       g_object_ref (zone);
+
                if (prop) {
                        /* Remove the VALUE parameter, to correspond to the actual value being set */
                        i_cal_property_remove_parameter_by_kind (prop, I_CAL_VALUE_PARAMETER);
@@ -925,6 +932,11 @@ ecepp_datetime_fill_component (ECompEditorPropertyPart *property_part,
                        g_clear_object (&value);
                        value = klass->i_cal_get_func (prop);
 
+                       /* The timezone can be dropped since libical 3.0.14, thus restore it
+                          before updating the TZID parameter */
+                       if (zone && value && !i_cal_time_is_null_time (value) && !i_cal_time_is_date (value))
+                               i_cal_time_set_timezone (value, zone);
+
                        cal_comp_util_update_tzid_parameter (prop, value);
                } else {
                        prop = klass->i_cal_new_func (value);
@@ -933,12 +945,18 @@ ecepp_datetime_fill_component (ECompEditorPropertyPart *property_part,
                        g_clear_object (&value);
                        value = klass->i_cal_get_func (prop);
 
+                       /* The timezone can be dropped since libical 3.0.14, thus restore it
+                          before updating the TZID parameter */
+                       if (zone && value && !i_cal_time_is_null_time (value) && !i_cal_time_is_date (value))
+                               i_cal_time_set_timezone (value, zone);
+
                        cal_comp_util_update_tzid_parameter (prop, value);
                        i_cal_component_add_property (component, prop);
                }
 
                g_clear_object (&value);
                g_clear_object (&prop);
+               g_clear_object (&zone);
        }
 }