python: enable summaries from model

This requires a change to the shared interface:
Making `getNodeFromPath` public.

This because Python is doing its own thing and identifying call-backs.

python/ql/lib/semmle/python/dataflow/new/FlowSummary.qll

@@ -90,39 +90,37 @@ abstract class SummarizedCallable extends LibraryCallable, Impl::Public::Summari
 }
 
 class RequiredSummaryComponentStack = Impl::Public::RequiredSummaryComponentStack;
-// // This gives access to getNodeFromPath, which is not constrained to `CallNode`s
-// // as `resolvedSummaryBase` is.
-// private import semmle.python.frameworks.data.internal.ApiGraphModels as AGM
-//
-// private class SummarizedCallableFromModel extends SummarizedCallable {
-//   string package;
-//   string type;
-//   string path;
-//   SummarizedCallableFromModel() {
-//     ModelOutput::relevantSummaryModel(package, type, path, _, _, _) and
-//     this = package + ";" + type + ";" + path
-//   }
-//   override CallCfgNode getACall() {
-//     exists(API::CallNode base |
-//       ModelOutput::resolvedSummaryBase(package, type, path, base) and
-//       result = base.getACall()
-//     )
-//   }
-//   override ArgumentNode getACallback() {
-//     exists(API::Node base |
-//       base = AGM::getNodeFromPath(package, type, path) and
-//       result = base.getAValueReachableFromSource()
-//     )
-//   }
-//   override predicate propagatesFlowExt(string input, string output, boolean preservesValue) {
-//     exists(string kind |
-//       ModelOutput::relevantSummaryModel(package, type, path, input, output, kind)
-//     |
-//       kind = "value" and
-//       preservesValue = true
-//       or
-//       kind = "taint" and
-//       preservesValue = false
-//     )
-//   }
-// }
+
+private class SummarizedCallableFromModel extends SummarizedCallable {
+  string type;
+  string path;
+
+  SummarizedCallableFromModel() {
+    ModelOutput::relevantSummaryModel(type, path, _, _, _) and
+    this = type + ";" + path
+  }
+
+  override CallCfgNode getACall() {
+    exists(API::CallNode base |
+      ModelOutput::resolvedSummaryBase(type, path, base) and
+      result = base.getACall()
+    )
+  }
+
+  override ArgumentNode getACallback() {
+    exists(API::Node base |
+      ModelOutput::resolvedSummaryRefBase(type, path, base) and
+      result = base.getAValueReachableFromSource()
+    )
+  }
+
+  override predicate propagatesFlowExt(string input, string output, boolean preservesValue) {
+    exists(string kind | ModelOutput::relevantSummaryModel(type, path, input, output, kind) |
+      kind = "value" and
+      preservesValue = true
+      or
+      kind = "taint" and
+      preservesValue = false
+    )
+  }
+}

python/ql/lib/semmle/python/frameworks/data/internal/ApiGraphModels.qll

@@ -643,6 +643,15 @@ module ModelOutput {
       baseNode = getInvocationFromPath(type, path)
     }
 
+    /**
+     * Holds if a `baseNode` is an invocation identified by the `type,path` part of a summary row.
+     */
+    cached
+    predicate resolvedSummaryRefBase(string type, string path, API::Node baseNode) {
+      summaryModel(type, path, _, _, _) and
+      baseNode = getNodeFromPath(type, path)
+    }
+
     /**
      * Holds if `node` is seen as an instance of `type` due to a type definition
      * contributed by a CSV model.