go-lang-plugin-org · Alioramus · Feb 26, 2017 · zolotov · Feb 28, 2017 · zolotov
diff --git a/resources/META-INF/gogland.xml b/resources/META-INF/gogland.xml
@@ -329,6 +329,9 @@
     <localInspection language="go" displayName="Multiple packages in directory declaration" groupPath="Go"
                      groupName="General" enabledByDefault="true" level="ERROR"
                      implementationClass="com.goide.inspections.GoMultiplePackagesInspection"/>
+    <localInspection language="go" displayName="String cannot be nil" groupPath="Go"
+                     groupName="General" enabledByDefault="true" level="ERROR"
+                     implementationClass="com.goide.inspections.GoStringCannotBeNilInspection"/>
     <localInspection language="go" displayName="Usage of cgo in tests is not supported" groupPath="Go"
                      groupName="General" enabledByDefault="true" level="ERROR"
                      implementationClass="com.goide.inspections.GoCgoInTestInspection"/>

diff --git a/resources/inspectionDescriptions/GoStringCannotBeNil.html b/resources/inspectionDescriptions/GoStringCannotBeNil.html
@@ -0,0 +1,21 @@
+<!--
+  ~ Copyright 2013-2017 Sergey Ignatov, Alexander Zolotov, Florin Patan
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~ http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+
+<html>
+<body>
+Inspects for string assignation or comparision to nil.
+</body>
+</html>
diff --git a/src/com/goide/inspections/GoStringCannotBeNilInspection.java b/src/com/goide/inspections/GoStringCannotBeNilInspection.java
@@ -0,0 +1,90 @@
+package com.goide.inspections;
+
+import com.goide.GoConstants;
+import com.goide.GoTypes;
+import com.goide.psi.*;
+import com.goide.psi.impl.GoElementFactory;
+import com.goide.psi.impl.GoPsiImplUtil;
+import com.goide.psi.impl.GoTypeUtil;
+import com.intellij.codeInspection.*;
+import com.intellij.openapi.project.Project;
+import com.intellij.psi.PsiElement;
+import com.intellij.psi.tree.IElementType;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.List;
+import java.util.stream.IntStream;
+
+public class GoStringCannotBeNilInspection extends GoInspectionBase {
+  public static final String QUICK_FIX_NAME = "Change to default value";
+  private static final String DEFAULT_STRING = "\"\"";
+  private static final String PROBLEM_DESCRIPTION = "String cannot be nil";
+
+  @NotNull
+  @Override
+  protected GoVisitor buildGoVisitor(@NotNull ProblemsHolder holder, @NotNull LocalInspectionToolSession session) {
+    return new GoVisitor() {
+
+      @Override
+      public void visitVarSpec(@NotNull GoVarSpec o) {
+        super.visitVarSpec(o);
+
+        if (o.getVarDefinitionList() == null) return;
+        o.getVarDefinitionList().forEach(var -> check(var, var != null ? var.getValue() : null));
+      }
+
+      @Override
+      public void visitAssignmentStatement(@NotNull GoAssignmentStatement o) {
+        super.visitAssignmentStatement(o);
+
+        if (o.getLeftHandExprList() == null) return;
+        List<GoExpression> rightSide = o.getExpressionList();
+        List<GoExpression> leftSide = o.getLeftHandExprList().getExpressionList();
+        if (leftSide == null || rightSide == null) return;
+
+        IntStream.range(0, Math.min(leftSide.size(), rightSide.size()))
+          .forEach(i -> check(leftSide.get(i), rightSide.get(i)));
+      }
+
+      @Override
+      public void visitBinaryExpr(@NotNull GoBinaryExpr o) {
+        super.visitBinaryExpr(o);
+        if (o.getOperator() == null || o.getOperator().getNode() == null) return;
+        IElementType type = o.getOperator().getNode().getElementType();
+        if (type == GoTypes.EQ || type == GoTypes.NOT_EQ) {
+          check(o.getLeft(), o.getRight());
+          check(o.getRight(), o.getLeft());
+        }
+      }
+
+      protected void check(GoTypeOwner var, GoExpression value) {
+
+        if (var == null || value == null) return;
+        GoType varType = var.getGoType(null);
+        if (!GoTypeUtil.isString(varType)) return;
+
+        if (value instanceof GoReferenceExpression && value.textMatches(GoConstants.NIL)
+            && GoPsiImplUtil.builtin(((GoReferenceExpression)value).resolve())) {
+
+          holder.registerProblem(value, PROBLEM_DESCRIPTION, ProblemHighlightType.GENERIC_ERROR_OR_WARNING,
+                                 new GoChangeStringToDefaultValueQuickFix());
+        }
+      }
+    };
+  }
+
+  private static class GoChangeStringToDefaultValueQuickFix extends LocalQuickFixBase {
+    public GoChangeStringToDefaultValueQuickFix() {
+      super(QUICK_FIX_NAME);
+    }
+
+    @Override
+    public void applyFix(@NotNull Project project, @NotNull ProblemDescriptor descriptor) {
+      PsiElement element = descriptor.getPsiElement();
+      if (element == null || !element.isValid()) return;
+      if (element instanceof GoExpression) {
+        element.replace(GoElementFactory.createExpression(project, DEFAULT_STRING));
+      }
+    }
+  }
+}
diff --git a/testData/inspections/string-assigned-to-nil/assignment-after.go b/testData/inspections/string-assigned-to-nil/assignment-after.go
@@ -0,0 +1,6 @@
+package main
+
+func main() {
+	var var1, var2, var3 string;
+	var1, var2, var3 = "nil", "", "text"
+}
diff --git a/testData/inspections/string-assigned-to-nil/assignment.go b/testData/inspections/string-assigned-to-nil/assignment.go
@@ -0,0 +1,6 @@
+package main
+
+func main() {
+	var var1, var2, var3 string;
+	var1, var2, var3 = "nil", <error descr="String cannot be nil"><caret>nil</error>, "text"
+}
diff --git a/testData/inspections/string-assigned-to-nil/comparison-after.go b/testData/inspections/string-assigned-to-nil/comparison-after.go
@@ -0,0 +1,6 @@
+package main
+
+func main() {
+	var var1 string;
+	"" == var1
+}
diff --git a/testData/inspections/string-assigned-to-nil/comparison.go b/testData/inspections/string-assigned-to-nil/comparison.go
@@ -0,0 +1,6 @@
+package main
+
+func main() {
+	var var1 string;
+	<error descr="String cannot be nil"><caret>nil</error> == var1
+}
diff --git a/testData/inspections/string-assigned-to-nil/nilVariable.go b/testData/inspections/string-assigned-to-nil/nilVariable.go
@@ -0,0 +1,6 @@
+package main
+
+func main() {
+	nil := "text"
+	var1 := nil
+}
diff --git a/testData/inspections/string-assigned-to-nil/tooManyValues-after.go b/testData/inspections/string-assigned-to-nil/tooManyValues-after.go
@@ -0,0 +1,5 @@
+package main
+
+func main() {
+	var var1, var2 string = "nil", "", 5 + 13
+}
diff --git a/testData/inspections/string-assigned-to-nil/tooManyValues.go b/testData/inspections/string-assigned-to-nil/tooManyValues.go
@@ -0,0 +1,5 @@
+package main
+
+func main() {
+	var var1, var2 string = "nil", <error descr="String cannot be nil"><caret>nil</error>, 5 + 13
+}
diff --git a/testData/inspections/string-assigned-to-nil/varDeclaration-after.go b/testData/inspections/string-assigned-to-nil/varDeclaration-after.go
@@ -0,0 +1,5 @@
+package main
+
+func main() {
+	var var1, var2, var3, var4 string = "nil", "", 5 + 13
+}
diff --git a/testData/inspections/string-assigned-to-nil/varDeclaration.go b/testData/inspections/string-assigned-to-nil/varDeclaration.go
@@ -0,0 +1,5 @@
+package main
+
+func main() {
+	var var1, var2, var3, var4 string = "nil", <error descr="String cannot be nil"><caret>nil</error>, 5 + 13
+}
diff --git a/tests/com/goide/inspections/GoStringCannotBeNilInspectionTest.java b/tests/com/goide/inspections/GoStringCannotBeNilInspectionTest.java
@@ -0,0 +1,55 @@
+/*
+ * Copyright 2013-2017 Sergey Ignatov, Alexander Zolotov, Florin Patan
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.goide.inspections;
+
+import com.goide.SdkAware;
+import com.goide.quickfix.GoQuickFixTestBase;
+
+@SdkAware
+public class GoStringCannotBeNilInspectionTest extends GoQuickFixTestBase {
+
+  @Override
+  protected void setUp() throws Exception {
+    super.setUp();
+    myFixture.enableInspections(GoStringCannotBeNilInspection.class);
+  }
+
+  public void testVarDeclaration() {
+    doTest(GoStringCannotBeNilInspection.QUICK_FIX_NAME, true);
+  }
+
+  public void testAssignment() {
+    doTest(GoStringCannotBeNilInspection.QUICK_FIX_NAME, true);
+  }
+
+  public void testTooManyValues() {
+    doTest(GoStringCannotBeNilInspection.QUICK_FIX_NAME, true);
+  }
+
+  public void testComparison() {
+    doTest(GoStringCannotBeNilInspection.QUICK_FIX_NAME, true);
+  }
+
+  public void testNilVariable() {
+    myFixture.testHighlighting(getTestName(true) + ".go");
+  }
+
+  @Override
+  protected String getBasePath() {
+    return "inspections/string-assigned-to-nil";
+  }
+}