[python] fix PR 10584

[Tom Tromey <tromey at redhat dot com>]

I'm checking this in on the python branch.

This fixes PR 10584, a case where a scalar varobj did not properly
update when the underlying value changed.

I've included a regression test.

Tom

2009-09-03  Tom Tromey  <tromey@redhat.com>

	* varobj.c (install_new_value): Properly set 'changed' when a
	pretty-printer is installed.
	(varobj_update): Push a changed varobj even if it has no
	children.

2009-09-03  Tom Tromey  <tromey@redhat.com>

	* gdb.python/python-prettyprint.c (string_1, string_2): New
	globals.
	* gdb.python/python-mi.exp: Add scalar regression test.

diff --git a/gdb/testsuite/gdb.python/python-mi.exp b/gdb/testsuite/gdb.python/python-mi.exp
index 018c6a2..7791775 100644
--- a/gdb/testsuite/gdb.python/python-mi.exp
+++ b/gdb/testsuite/gdb.python/python-mi.exp
@@ -61,6 +61,17 @@ mi_delete_varobj container "delete varobj"
 
 mi_gdb_test "-enable-pretty-printing" ""
 
+mi_create_varobj_checked string string_1 \
+    "struct string_repr" \
+    "create string_1 varobj"
+
+mi_gdb_test "-data-evaluate-expression \"string_1 = string_2\"" ".*" \
+    "assign string_1 from string_2"
+
+mi_gdb_test "-var-update string" \
+    "\\^done,changelist=\\\[{name=\"string\",in_scope=\"true\",type_changed=\"false\",has_more=\"0\"}\\\]" \
+    "update string varobj after assignment"
+
 mi_create_dynamic_varobj container c \
   "create container varobj"
 
diff --git a/gdb/testsuite/gdb.python/python-prettyprint.c b/gdb/testsuite/gdb.python/python-prettyprint.c
index 5fbd534..adf66b5 100644
--- a/gdb/testsuite/gdb.python/python-prettyprint.c
+++ b/gdb/testsuite/gdb.python/python-prettyprint.c
@@ -155,6 +155,9 @@ struct nullstr
   char *s;
 };
 
+struct string_repr string_1 = { { "one" } };
+struct string_repr string_2 = { { "two" } };
+
 int
 main ()
 {
diff --git a/gdb/varobj.c b/gdb/varobj.c
index b6a16d2..e1dec23 100644
--- a/gdb/varobj.c
+++ b/gdb/varobj.c
@@ -1551,9 +1551,6 @@ install_new_value (struct varobj *var, struct value *value, int initial)
   var->value = value;
   if (value != NULL)
     value_incref (value);
-  if (var->print_value)
-    xfree (var->print_value);
-  var->print_value = print_value;
   if (value && value_lazy (value) && intentionally_not_fetched)
     var->not_fetched = 1;
   else
@@ -1562,6 +1559,19 @@ install_new_value (struct varobj *var, struct value *value, int initial)
 
   install_new_value_visualizer (var);
 
+  /* If we installed a pretty-printer, re-compare the printed version
+     to see if the variable changed.  */
+  if (var->pretty_printer)
+    {
+      xfree (print_value);
+      print_value = value_get_print_value (var->value, var->format, var);
+      if (!var->print_value || strcmp (var->print_value, print_value) != 0)
+	changed = 1;
+    }
+  if (var->print_value)
+    xfree (var->print_value);
+  var->print_value = print_value;
+
   gdb_assert (!var->value || value_type (var->value));
 
   return changed;
@@ -1746,11 +1756,14 @@ VEC(varobj_update_result) *varobj_update (struct varobj **varp, int explicit)
 		 it as unchanged -- presumably, such varobj is not yet
 		 expanded in the UI, so we need not bother getting
 		 it.  */
-	      if (varobj_has_more (v, 0))
-		continue;
+	      if (!varobj_has_more (v, 0))
+		{
+		  update_dynamic_varobj_children (v, NULL, NULL, &dummy, 0, 0);
+		  if (varobj_has_more (v, 0))
+		    r.changed = 1;
+		}
 
-	      update_dynamic_varobj_children (v, NULL, NULL, &dummy, 0, 0);
-	      if (varobj_has_more (v, 0))
+	      if (r.changed)
 		VEC_safe_push (varobj_update_result, result, &r);
 
 	      continue;