Merge pull request livecode#3859 from livecodeali/bugfix-16970

peter-b · peter-b · commit e5569ea10fff · 2016-04-07T10:56:28.000+01:00
[[ Bug 16970 ]] Fix crash when setting screenPixelScale
diff --git a/docs/notes/bugfix-16970.md b/docs/notes/bugfix-16970.md
@@ -0,0 +1 @@
+# Prevent crash when setting the screenPixelScale
diff --git a/engine/src/exec.cpp b/engine/src/exec.cpp
@@ -1792,6 +1792,8 @@ static bool MCPropertyParsePointList(MCStringRef p_input, char_t p_delimiter, ui
 
 void MCExecFetchProperty(MCExecContext& ctxt, const MCPropertyInfo *prop, void *mark, MCExecValue& r_value)
 {
+    MCAssert(prop -> getter != nil);
+    
     switch(prop -> type)
     {
         case kMCPropertyTypeAny:
@@ -2592,6 +2594,8 @@ void MCExecFetchProperty(MCExecContext& ctxt, const MCPropertyInfo *prop, void *
 
 void MCExecStoreProperty(MCExecContext& ctxt, const MCPropertyInfo *prop, void *mark, MCExecValue p_value)
 {
+    MCAssert(prop -> setter != nil);
+    
     switch(prop -> type)
     {
         case kMCPropertyTypeAny:
diff --git a/engine/src/property.cpp b/engine/src/property.cpp
@@ -5430,14 +5430,13 @@ void MCProperty::eval_global_property_ctxt(MCExecContext& ctxt, MCExecValue& r_v
 	if (!MCPropertyInfoTableLookup(which, effective, t_info, t_is_array_prop))
         t_info = lookup_mode_property(getmodepropertytable(), which, effective, t_is_array_prop);
         
-    if (t_info != nil)
+    if (t_info != nil && t_info -> getter != nil)
     {
         MCExecFetchProperty(ctxt, t_info, *t_index, r_value);
         return;
 	}
 
-    MCeerror->add(EE_PROPERTY_NOPROP, line, pos);
-    ctxt . Throw();
+    ctxt . LegacyThrow(EE_PROPERTY_NOPROP);
 }
 
 void MCProperty::eval_object_property_ctxt(MCExecContext& ctxt, MCExecValue& r_value)
@@ -5534,14 +5533,13 @@ void MCProperty::set_global_property(MCExecContext& ctxt, MCExecValue p_value)
     if (!MCPropertyInfoTableLookup(which, effective, t_info, t_is_array_prop))
         t_info = lookup_mode_property(getmodepropertytable(), which, effective, t_is_array_prop);
     
-    if (t_info != nil)
+    if (t_info != nil && t_info -> setter != nil)
     {
         MCExecStoreProperty(ctxt, t_info, *t_index, p_value);
         return;
 	}
     
-    MCeerror->add(EE_PROPERTY_CANTSET, line, pos);
-    ctxt . Throw();
+    ctxt . LegacyThrow(EE_PROPERTY_CANTSET);
 }
 
 void MCProperty::set_object_property(MCExecContext& ctxt, MCExecValue p_value)
diff --git a/tests/lcs/_testlib.livecodescript b/tests/lcs/_testlib.livecodescript
@@ -113,6 +113,16 @@ on TestAssertBroken pDescription, pExpectTrue, pReasonBroken
    _TestOutput pExpectTrue, pDescription, "TODO", pReasonBroken
 end TestAssertBroken
 
+on TestAssertThrow pDescription, pHandler, pTarget, pErrorCode
+   local tError
+   try
+      dispatch pHandler to pTarget
+    catch tError
+    end try
+    
+    TestAssert pDescription, pErrorCode is item 1 of line 1 of tError
+end TestAssertThrow
+
 on ErrorDialog executionError, parseError
    write executionError & return to stderr
    quit 1
diff --git a/tests/lcs/core/engine/globalproperties.livecodescript b/tests/lcs/core/engine/globalproperties.livecodescript
@@ -0,0 +1,27 @@
+﻿script "CoreEngineGlobalProperties"
+/*
+Copyright (C) 2015 LiveCode Ltd.
+
+This file is part of LiveCode.
+
+LiveCode is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License v3 as published by the Free
+Software Foundation.
+
+LiveCode is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with LiveCode.  If not see <http://www.gnu.org/licenses/>.  */
+
+on _TestSetReadOnlyProperty
+	set the screenPixelScale to 2
+end _TestSetReadOnlyProperty
+
+constant kCantSetPropertyCode = 448
+on TestSetReadOnlyProperty
+	TestAssertThrow "setting read-only global property throws", \
+		 "_TestSetReadOnlyProperty", the long id of me, kCantSetPropertyCode
+end TestSetReadOnlyProperty

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1 @@`
	`1`	`+# Prevent crash when setting the screenPixelScale`
Original file line number	Diff line number	Diff line change
`@@ -1792,6 +1792,8 @@ static bool MCPropertyParsePointList(MCStringRef p_input, char_t p_delimiter, ui`
`1792`	`1792`
`1793`	`1793`	`void MCExecFetchProperty(MCExecContext& ctxt, const MCPropertyInfo prop, void mark, MCExecValue& r_value)`
`1794`	`1794`	`{`
	`1795`	`+ MCAssert(prop -> getter != nil);`
	`1796`	`+`
`1795`	`1797`	`switch(prop -> type)`
`1796`	`1798`	`{`
`1797`	`1799`	`case kMCPropertyTypeAny:`
`@@ -2592,6 +2594,8 @@ void MCExecFetchProperty(MCExecContext& ctxt, const MCPropertyInfo prop, void `
`2592`	`2594`
`2593`	`2595`	`void MCExecStoreProperty(MCExecContext& ctxt, const MCPropertyInfo prop, void mark, MCExecValue p_value)`
`2594`	`2596`	`{`
	`2597`	`+ MCAssert(prop -> setter != nil);`
	`2598`	`+`
`2595`	`2599`	`switch(prop -> type)`
`2596`	`2600`	`{`
`2597`	`2601`	`case kMCPropertyTypeAny:`
Original file line number	Diff line number	Diff line change
`@@ -5430,14 +5430,13 @@ void MCProperty::eval_global_property_ctxt(MCExecContext& ctxt, MCExecValue& r_v`
`5430`	`5430`	`if (!MCPropertyInfoTableLookup(which, effective, t_info, t_is_array_prop))`
`5431`	`5431`	`t_info = lookup_mode_property(getmodepropertytable(), which, effective, t_is_array_prop);`
`5432`	`5432`
`5433`		`- if (t_info != nil)`
	`5433`	`+ if (t_info != nil && t_info -> getter != nil)`
`5434`	`5434`	`{`
`5435`	`5435`	`MCExecFetchProperty(ctxt, t_info, *t_index, r_value);`
`5436`	`5436`	`return;`
`5437`	`5437`	`}`
`5438`	`5438`
`5439`		`- MCeerror->add(EE_PROPERTY_NOPROP, line, pos);`
`5440`		`- ctxt . Throw();`
	`5439`	`+ ctxt . LegacyThrow(EE_PROPERTY_NOPROP);`
`5441`	`5440`	`}`
`5442`	`5441`
`5443`	`5442`	`void MCProperty::eval_object_property_ctxt(MCExecContext& ctxt, MCExecValue& r_value)`
`@@ -5534,14 +5533,13 @@ void MCProperty::set_global_property(MCExecContext& ctxt, MCExecValue p_value)`
`5534`	`5533`	`if (!MCPropertyInfoTableLookup(which, effective, t_info, t_is_array_prop))`
`5535`	`5534`	`t_info = lookup_mode_property(getmodepropertytable(), which, effective, t_is_array_prop);`
`5536`	`5535`
`5537`		`- if (t_info != nil)`
	`5536`	`+ if (t_info != nil && t_info -> setter != nil)`
`5538`	`5537`	`{`
`5539`	`5538`	`MCExecStoreProperty(ctxt, t_info, *t_index, p_value);`
`5540`	`5539`	`return;`
`5541`	`5540`	`}`
`5542`	`5541`
`5543`		`- MCeerror->add(EE_PROPERTY_CANTSET, line, pos);`
`5544`		`- ctxt . Throw();`
	`5542`	`+ ctxt . LegacyThrow(EE_PROPERTY_CANTSET);`
`5545`	`5543`	`}`
`5546`	`5544`
`5547`	`5545`	`void MCProperty::set_object_property(MCExecContext& ctxt, MCExecValue p_value)`