Merge pull request #9255 from michaelnebel/csharp/test-clearscontent

C#: Remove default clears content.

Author: michaelnebel

csharp/ql/lib/semmle/code/csharp/dataflow/FlowSummary.qll

@@ -139,28 +139,6 @@ private class RecordConstructorFlow extends SummarizedCallable {
   }
 }
 
-private class SummarizedCallableDefaultClearsContent extends Impl::Public::SummarizedCallable {
-  SummarizedCallableDefaultClearsContent() {
-    this instanceof Impl::Public::SummarizedCallable or none()
-  }
-
-  // By default, we assume that all stores into arguments are definite
-  override predicate clearsContent(ParameterPosition pos, DataFlow::ContentSet content) {
-    exists(SummaryComponentStack output, SummaryComponent target |
-      this.propagatesFlow(_, output, _) and
-      output.drop(_) =
-        SummaryComponentStack::push(SummaryComponent::content(content),
-          SummaryComponentStack::singleton(target)) and
-      not content instanceof DataFlow::ElementContent
-    |
-      target = SummaryComponent::argument(pos.getPosition())
-      or
-      target = SummaryComponent::qualifier() and
-      pos.isThisParameter()
-    )
-  }
-}
-
 class RequiredSummaryComponentStack = Impl::Public::RequiredSummaryComponentStack;
 
 private class RecordConstructorFlowRequiredSummaryComponentStack extends RequiredSummaryComponentStack {

csharp/ql/lib/semmle/code/csharp/dataflow/internal/FlowSummaryImpl.qll

@@ -933,7 +933,8 @@ module Private {
         summaryElement(this, inSpec, outSpec, kind, false)
         or
         summaryElement(this, inSpec, outSpec, kind, true) and
-        not summaryElement(this, _, _, _, false)
+        not summaryElement(this, _, _, _, false) and
+        not this.clearsContent(_, _)
       }
 
       override predicate propagatesFlow(

csharp/ql/test/library-tests/dataflow/external-models/steps.expected

@@ -20,5 +20,5 @@ summarySetterStep
 | Steps.cs:34:37:34:37 | 0 | Steps.cs:34:13:34:16 | [post] this access | Steps.cs:63:13:63:20 | property Property |
 | Steps.cs:38:36:38:36 | 0 | Steps.cs:38:13:38:16 | [post] this access | file://:0:0:0:0 | element |
 clearsContent
-| Steps.cs:61:14:61:28 | StepFieldSetter | Steps.cs:57:13:57:17 | field Field | this |
-| Steps.cs:67:14:67:31 | StepPropertySetter | Steps.cs:63:13:63:20 | property Property | this |
+| Steps.cs:61:14:61:28 | StepFieldSetter | file://:0:0:0:0 | element | this |
+| Steps.cs:67:14:67:31 | StepPropertySetter | file://:0:0:0:0 | element | this |

csharp/ql/test/library-tests/dataflow/external-models/steps.ql

@@ -5,7 +5,7 @@ import semmle.code.csharp.dataflow.FlowSummary
 import semmle.code.csharp.dataflow.internal.FlowSummaryImpl as FlowSummaryImpl
 import CsvValidation
 
-class SummaryModelTest extends SummaryModelCsv {
+private class SummaryModelTest extends SummaryModelCsv {
   override predicate row(string row) {
     row =
       [
@@ -28,6 +28,18 @@ class SummaryModelTest extends SummaryModelCsv {
   }
 }
 
+private class SummarizedCallableClear extends SummarizedCallable {
+  SummarizedCallableClear() {
+    this.getName() = ["StepPropertySetter", "StepFieldSetter"] and
+    this.getFile().getBaseName() = "Steps.cs"
+  }
+
+  override predicate clearsContent(ParameterPosition pos, DataFlow::ContentSet content) {
+    pos.isThisParameter() and
+    content instanceof DataFlow::ElementContent
+  }
+}
+
 query predicate summaryThroughStep(
   DataFlow::Node node1, DataFlow::Node node2, boolean preservesValue
 ) {

java/ql/lib/semmle/code/java/dataflow/internal/FlowSummaryImpl.qll

@@ -933,7 +933,8 @@ module Private {
         summaryElement(this, inSpec, outSpec, kind, false)
         or
         summaryElement(this, inSpec, outSpec, kind, true) and
-        not summaryElement(this, _, _, _, false)
+        not summaryElement(this, _, _, _, false) and
+        not this.clearsContent(_, _)
       }
 
       override predicate propagatesFlow(

ruby/ql/lib/codeql/ruby/dataflow/internal/FlowSummaryImpl.qll

@@ -933,7 +933,8 @@ module Private {
         summaryElement(this, inSpec, outSpec, kind, false)
         or
         summaryElement(this, inSpec, outSpec, kind, true) and
-        not summaryElement(this, _, _, _, false)
+        not summaryElement(this, _, _, _, false) and
+        not this.clearsContent(_, _)
       }
 
       override predicate propagatesFlow(