SONARPY-3194 Collect the CallGraph (#405)

GitOrigin-RevId: 41829c761a1e27f48b06cb01a0d20619b70dc397

Author: Seppli11

python-frontend/src/main/java/org/sonar/plugins/python/api/PythonVisitorContext.java

@@ -38,6 +38,7 @@
 import org.sonar.python.semantic.v2.TypeInferenceV2;
 import org.sonar.python.semantic.v2.callgraph.CallGraph;
 import org.sonar.python.semantic.v2.TypeTable;
+import org.sonar.python.semantic.v2.callgraph.CallGraphCollector;
 import org.sonar.python.types.v2.TypeChecker;
 
 public class PythonVisitorContext extends PythonInputFileContext {
@@ -152,7 +153,7 @@ public Builder projectLevelSymbolTable(ProjectLevelSymbolTable projectLevelSymbo
     }
 
     public Builder typeTable(TypeTable typeTable) {
-      this.typeTable = Optional.ofNullable(typeTable);
+      this.typeTable = Optional.of(typeTable);
       return this;
     }
 
@@ -177,7 +178,7 @@ public Builder moduleType(ModuleType moduleType) {
     }
 
     public Builder callGraph(CallGraph callGraph) {
-      this.callGraph = Optional.ofNullable(callGraph);
+      this.callGraph = Optional.of(callGraph);
       return this;
     }
 
@@ -192,6 +193,8 @@ public PythonVisitorContext build() {
         return new TypeInferenceV2(finalTypeTable, pythonFile, symbolTableV2, pkgName).inferModuleType(rootTree);
       });
 
+      var finalCallGraph = callGraph.orElseGet(() -> CallGraphCollector.collectCallGraph(rootTree));
+
       return new PythonVisitorContext(
         rootTree,
         pythonFile,
@@ -202,7 +205,7 @@ public PythonVisitorContext build() {
         projectConfiguration.orElse(new ProjectConfiguration()),
         mt,
         new TypeChecker(finalTypeTable),
-        callGraph.orElse(CallGraph.EMPTY)
+        finalCallGraph
       );
     }
 

python-frontend/src/main/java/org/sonar/python/semantic/v2/callgraph/CallGraphCollector.java

@@ -0,0 +1,98 @@
+/*
+ * SonarQube Python Plugin
+ * Copyright (C) 2011-2025 SonarSource SA
+ * mailto:info AT sonarsource DOT com
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the Sonar Source-Available License Version 1, as published by SonarSource SA.
+ *
+ * This program 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 Sonar Source-Available License for more details.
+ *
+ * You should have received a copy of the Sonar Source-Available License
+ * along with this program; if not, see https://sonarsource.com/license/ssal/
+ */
+package org.sonar.python.semantic.v2.callgraph;
+
+import java.util.Optional;
+import java.util.Set;
+import java.util.stream.Collectors;
+import org.sonar.plugins.python.api.tree.BaseTreeVisitor;
+import org.sonar.plugins.python.api.tree.CallExpression;
+import org.sonar.plugins.python.api.tree.FileInput;
+import org.sonar.plugins.python.api.tree.FunctionDef;
+import org.sonar.plugins.python.api.tree.Tree;
+import org.sonar.plugins.python.api.types.v2.FunctionType;
+import org.sonar.plugins.python.api.types.v2.ModuleType;
+import org.sonar.plugins.python.api.types.v2.PythonType;
+import org.sonar.plugins.python.api.types.v2.UnionType;
+import org.sonar.plugins.python.api.types.v2.UnknownType.UnresolvedImportType;
+import org.sonar.python.tree.TreeUtils;
+
+public class CallGraphCollector {
+  private CallGraphCollector() {
+  }
+
+  public static CallGraph collectCallGraph(FileInput rootTree) {
+    var visitor = new Visitor();
+    rootTree.accept(visitor);
+    return visitor.build();
+  }
+    
+  private static class Visitor extends BaseTreeVisitor {
+    private final CallGraph.Builder callGraphBuilder = new CallGraph.Builder();
+
+    @Override
+    public void visitCallExpression(CallExpression callExpr) {
+      super.visitCallExpression(callExpr);
+      getCalledFunctionFqn(callExpr).ifPresent(calledFunctionFqn -> 
+        getEnclosedFunctionFqn(callExpr).ifPresent(enclosedFunctionFqn -> 
+          callGraphBuilder.addUsage(enclosedFunctionFqn, calledFunctionFqn)
+        )
+      );
+    }
+
+    private static Optional<String> getCalledFunctionFqn(CallExpression callExpr) {
+      var calleeType = callExpr.callee().typeV2();
+      return CallGraphCollector.getFqn(calleeType);
+    }
+
+    private static Optional<String> getEnclosedFunctionFqn(CallExpression callExpr) {
+      Tree enclosingFuncDefTree = TreeUtils.firstAncestorOfKind(callExpr, Tree.Kind.FUNCDEF, Tree.Kind.LAMBDA);
+      if(enclosingFuncDefTree instanceof FunctionDef enclosingFunctionDef) {
+        return CallGraphCollector.getFqn(enclosingFunctionDef.name().typeV2());
+      }
+      // lambdas are not supported; thus returning empty
+      return Optional.empty();
+    }
+
+    public CallGraph build() {
+      return callGraphBuilder.build();
+    }
+  }
+
+  private static Optional<String> getFqn(PythonType type) {
+    if(type instanceof FunctionType functionType) {
+      return Optional.of(functionType.fullyQualifiedName());
+    } else if (type instanceof ModuleType moduleType) {
+      return Optional.of(moduleType.fullyQualifiedName());
+    } else if(type instanceof UnresolvedImportType unresolvedImportType) {
+      return Optional.of(unresolvedImportType.importPath());
+    } else if(type instanceof UnionType unionType) {
+      Set<String> unionFqnSet = unionType.candidates().stream()
+        .flatMap(candidate -> getFqn(candidate).stream())
+        .collect(Collectors.toSet());
+      
+      if (unionFqnSet.size() == 1) {
+        return unionFqnSet.stream().findFirst();
+      } else {
+        // Multiple candidates, cannot determine a single FQN
+        return Optional.empty(); 
+      }
+    } else {
+      return Optional.empty();
+    }
+  }
+}

python-frontend/src/test/java/org/sonar/plugins/python/api/PythonVisitorContextTest.java

@@ -34,6 +34,8 @@
 import org.sonar.python.parser.PythonParser;
 import org.sonar.python.semantic.ProjectLevelSymbolTable;
 import org.sonar.python.semantic.v2.ProjectLevelTypeTable;
+import org.sonar.python.semantic.v2.callgraph.CallGraph;
+import org.sonar.python.semantic.v2.callgraph.CallGraphNode;
 import org.sonar.python.tree.FileInputImpl;
 import org.sonar.python.tree.PythonTreeMaker;
 
@@ -98,6 +100,31 @@ void globalSymbols() {
     assertThat(fileInput.globalVariables()).extracting(Symbol::name).containsExactlyInAnyOrder("a", "b");
   }
 
+  @Test
+  void callGraph() {
+    String code = """
+        def bar():
+          pass
+
+        def foo():
+          bar()
+        """;
+    FileInput fileInput = new PythonTreeMaker().fileInput(PythonParser.create().parse(code));
+    PythonFile pythonFile = pythonFile("my_module.py");
+
+    var ctx = new PythonVisitorContext.Builder(fileInput, pythonFile)
+      .packageName("my_package")
+      .cacheContext(CacheContextImpl.dummyCache())
+      .build();
+
+    CallGraph callGraph = ctx.callGraph();
+
+    assertThat(callGraph.getUsages("my_package.my_module.foo")).isEmpty();
+    assertThat(callGraph.getUsages("my_package.my_module.bar")).extracting(CallGraphNode::fqn)
+      .containsExactly("my_package.my_module.foo");
+
+  }
+
   @Test
   void sonar_product() {
     CacheContextImpl cacheContext = CacheContextImpl.dummyCache();