Ruby: add Call::isSafeNavigation

Author: aibaars

ruby/ql/lib/codeql/ruby/ast/Call.qll

@@ -105,6 +105,14 @@ class MethodCall extends Call instanceof MethodCallImpl {
    */
   final Block getBlock() { result = super.getBlockImpl() }
 
+  /**
+   * Holds if the safe nagivation operator (`&.`) is used in this call.
+   * ```rb
+   * foo&.empty?
+   * ```
+   */
+  final predicate isSafeNavigation() { super.isSafeNavigationImpl() }
+
   override string toString() { result = "call to " + this.getMethodName() }
 
   override AstNode getAChild(string pred) {

ruby/ql/lib/codeql/ruby/ast/internal/Call.qll

@@ -28,6 +28,8 @@ abstract class MethodCallImpl extends CallImpl, TMethodCall {
   abstract string getMethodNameImpl();
 
   abstract Block getBlockImpl();
+
+  predicate isSafeNavigationImpl() { none() }
 }
 
 class MethodCallSynth extends MethodCallImpl, TMethodCallSynth {
@@ -89,6 +91,10 @@ class RegularMethodCall extends MethodCallImpl, TRegularMethodCall {
   final override int getNumberOfArgumentsImpl() { result = count(g.getArguments().getChild(_)) }
 
   final override Block getBlockImpl() { toGenerated(result) = g.getBlock() }
+
+  final override predicate isSafeNavigationImpl() {
+    g.getOperator().(Ruby::Token).getValue() = "&."
+  }
 }
 
 class ElementReferenceImpl extends MethodCallImpl, TElementReference {

ruby/ql/test/library-tests/ast/Ast.expected

@@ -739,6 +739,15 @@ calls/calls.rb:
 #  356|       getStmt: [LocalVariableAccess] y
 #  357|       getStmt: [MethodCall] call to unknown_call
 #  357|         getReceiver: [SelfVariableAccess] self
+#  361|   getStmt: [MethodCall] call to empty?
+#  361|     getReceiver: [MethodCall] call to list
+#  361|       getReceiver: [SelfVariableAccess] self
+#  362|   getStmt: [MethodCall] call to empty?
+#  362|     getReceiver: [MethodCall] call to list
+#  362|       getReceiver: [SelfVariableAccess] self
+#  363|   getStmt: [MethodCall] call to empty?
+#  363|     getReceiver: [MethodCall] call to list
+#  363|       getReceiver: [SelfVariableAccess] self
 control/cases.rb:
 #    1| [Toplevel] cases.rb
 #    2|   getStmt: [AssignExpr] ... = ...

ruby/ql/test/library-tests/ast/TreeSitter.expected

@@ -1269,6 +1269,18 @@ calls/calls.rb:
 #  356|         2: [Identifier] y
 #  357|         3: [Identifier] unknown_call
 #  358|         4: [ReservedWord] end
+#  361|   117: [Call] Call
+#  361|     0: [Identifier] list
+#  361|     1: [ReservedWord] .
+#  361|     2: [Identifier] empty?
+#  362|   118: [Call] Call
+#  362|     0: [Identifier] list
+#  362|     1: [ReservedWord] &.
+#  362|     2: [Identifier] empty?
+#  363|   119: [Call] Call
+#  363|     0: [Identifier] list
+#  363|     1: [ReservedWord] ::
+#  363|     2: [Identifier] empty?
 #    1| [Comment] # call with no receiver, arguments, or block
 #    4| [Comment] # call whose name is a scope resolution
 #    7| [Comment] # call whose name is a global scope resolution
@@ -1342,6 +1354,7 @@ calls/calls.rb:
 #  330| [Comment] # forward parameter and forwarded arguments
 #  339| [Comment] # for loop over nested array
 #  349| [Comment] # calls inside lambdas
+#  360| [Comment] # calls with various call operators
 constants/constants.rb:
 #    1| [Program] Program
 #    1|   0: [Module] Module

ruby/ql/test/library-tests/ast/calls/calls.expected

@@ -372,6 +372,12 @@ callsWithReceiver
 | calls.rb:352:13:352:17 | call to foo | calls.rb:352:13:352:17 | self |
 | calls.rb:353:13:353:24 | call to unknown_call | calls.rb:353:13:353:24 | self |
 | calls.rb:357:3:357:14 | call to unknown_call | calls.rb:357:3:357:14 | self |
+| calls.rb:361:1:361:4 | call to list | calls.rb:361:1:361:4 | self |
+| calls.rb:361:1:361:11 | call to empty? | calls.rb:361:1:361:4 | call to list |
+| calls.rb:362:1:362:4 | call to list | calls.rb:362:1:362:4 | self |
+| calls.rb:362:1:362:12 | call to empty? | calls.rb:362:1:362:4 | call to list |
+| calls.rb:363:1:363:4 | call to list | calls.rb:363:1:363:4 | self |
+| calls.rb:363:1:363:12 | call to empty? | calls.rb:363:1:363:4 | call to list |
 callsWithBlock
 | calls.rb:17:1:17:17 | call to foo | calls.rb:17:5:17:17 | { ... } |
 | calls.rb:20:1:22:3 | call to foo | calls.rb:20:5:22:3 | do ... end |
@@ -424,3 +430,5 @@ setterCalls
 | calls.rb:318:1:318:10 | call to count= |
 | calls.rb:319:1:319:6 | call to []= |
 | calls.rb:320:1:320:32 | call to []= |
+callsWithSafeNavigationOperator
+| calls.rb:362:1:362:12 | call to empty? |

ruby/ql/test/library-tests/ast/calls/calls.ql

@@ -31,3 +31,5 @@ query predicate superCallsWithArguments(SuperCall c, int n, Expr argN) { argN =
 query predicate superCallsWithBlock(SuperCall c, Block b) { b = c.getBlock() }
 
 query predicate setterCalls(SetterMethodCall c) { any() }
+
+query predicate callsWithSafeNavigationOperator(MethodCall c) { c.isSafeNavigation() }

ruby/ql/test/library-tests/ast/calls/calls.rb

@@ -356,3 +356,8 @@ def foo(a, b, ...)
   y
   unknown_call
 end
+
+# calls with various call operators
+list.empty?
+list&.empty?
+list::empty?