Merge pull request #1615 from geoffw0/exprowninit

Robert Marsh · web-flow · commit fa43ae241d57 · 2019-07-24T12:13:24.000-07:00
CPP: Test + workaround for UseInOwnInitializer.ql
diff --git a/change-notes/1.22/analysis-cpp.md b/change-notes/1.22/analysis-cpp.md
@@ -17,6 +17,7 @@
 | No space for zero terminator (`cpp/no-space-for-terminator`) | Fewer false positive results | False positives involving strings that are not null-terminated have been excluded. |
 | Suspicious pointer scaling (`cpp/suspicious-pointer-scaling`) | Lower precision | The precision of this query has been reduced to "medium". This coding pattern is used intentionally and safely in a number of real-world projects. Results are no longer displayed on LGTM unless you choose to display them. |
 | Non-constant format string (`cpp/non-constant-format`) | Fewer false positive results | Rewritten using the taint-tracking library. |
+| Variable used in its own initializer (`cpp/use-in-own-initializer`) | Fewer false positive results | False positives for constant variables with the same name in different namespaces have been removed. |
 
 ## Changes to QL libraries
 
diff --git a/cpp/ql/src/Likely Bugs/UseInOwnInitializer.ql b/cpp/ql/src/Likely Bugs/UseInOwnInitializer.ql
@@ -32,6 +32,7 @@ where va.initializesItself(v, init)
     exists (CrementOperation crement | crement.getAnOperand() = va)
   )
   and not va.isUnevaluated()
+  and not v.isConst()
   and not (
     va.getParent() = init and
     exists(MacroInvocation mi |
diff --git a/cpp/ql/test/query-tests/Likely Bugs/UseInOwnInitializer/test.cpp b/cpp/ql/test/query-tests/Likely Bugs/UseInOwnInitializer/test.cpp
@@ -66,3 +66,26 @@ void test11() {
 void test12() {
 	self_initialize(int, x); // GOOD (statement is from a macro)
 }
+
+namespace ns1
+{
+	const int v2 = 1;
+	const int v4 = 1;
+	const int v6 = 1;
+};
+
+namespace ns2
+{
+	const int v1 = ns1::v2; // GOOD
+	const int v2 = ns1::v2; // GOOD [produces INVALID_KEY trap warning]
+};
+
+const int v3 = ns1::v4; // GOOD
+const int v4 = ns1::v4; // GOOD
+
+namespace ns3
+{
+	const int v5 = ns1::v6 + 1; // GOOD
+	const int v6 = ns1::v6 + 1; // GOOD  [produces INVALID_KEY trap warning]
+	const int v7 = ns3::v7; // BAD [NOT DETECTED]
+};

Original file line number	Diff line number	Diff line change
`@@ -32,6 +32,7 @@ where va.initializesItself(v, init)`
`32`	`32`	`exists (CrementOperation crement \| crement.getAnOperand() = va)`
`33`	`33`	`)`
`34`	`34`	`and not va.isUnevaluated()`
	`35`	`+ and not v.isConst()`
`35`	`36`	`and not (`
`36`	`37`	`va.getParent() = init and`
`37`	`38`	`exists(MacroInvocation mi \|`