Strings cannot be nil inspection

go-lang-plugin-org · Feb 19, 2017 · 54d3087 · 54d3087
1 parent eb5fc24
commit 54d3087
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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 +1,95 @@
+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.GoTypeUtil;
+import com.intellij.codeInspection.LocalInspectionToolSession;
+import com.intellij.codeInspection.LocalQuickFix;
+import com.intellij.codeInspection.ProblemDescriptor;
+import com.intellij.codeInspection.ProblemsHolder;
+import com.intellij.openapi.project.Project;
+import com.intellij.psi.PsiElement;
+import org.jetbrains.annotations.Nls;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.List;
+
+public class GoStringCannotBeNilInspection extends GoInspectionBase{
+
+  private static final String DEFAULT_STRING = "\"\"";
+  private static final String PROBLEM_DESC = "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);
+        for(int i = 0; i < o.getExpressionList().size(); ++i){
+          check(o.getVarDefinitionList().get(i).getGoType(null), o.getVarDefinitionList().get(i).getValue());
+        }
+      }
+
+
+      @Override
+      public void visitAssignOp(@NotNull GoAssignOp o) {
+        super.visitAssignOp(o);
+        PsiElement[] right = o.getParent().getChildren();
+        if(right == null) return;
+
+        List<GoExpression> left = ((GoLeftHandExprList)right[0]).getExpressionList();
+        if(left == null) return;
+
+        for(int i = 0; i < left.size(); ++i){
+          GoExpression var = left.get(i);
+          PsiElement value = right[right.length - (left.size() - i)];
+
+          if(value instanceof GoExpression){
+            check(var.getGoType(null), (GoExpression)value);
+          }
+
+        }
+      }
+
+      @Override
+      public void visitBinaryExpr(@NotNull GoBinaryExpr o) {
+        super.visitBinaryExpr(o);
+
+        if(o.getOperator().getText().equals(GoTypes.EQ.toString()) ||
+           o.getOperator().getText().equals(GoTypes.NOT_EQ.toString())){
+          check(o.getLeft().getGoType(null), o.getRight());
+          check(o.getRight().getGoType(null), o.getLeft());
+        }
+      }
+
+      protected void check(GoType var, GoExpression value){
+
+        if(var == null || value == null) return;
+
+        if(GoTypeUtil.isString(var)) {
+          if(value.getText().equals(GoConstants.NIL)){
+
+            holder.registerProblem(value, PROBLEM_DESC, new LocalQuickFix() {
+              @Nls
+              @NotNull
+              @Override
+              public String getFamilyName() {
+                return "Change to default value";
+              }
+
+              @Override
+              public void applyFix(@NotNull Project project, @NotNull ProblemDescriptor descriptor) {
+                value.replace(GoElementFactory.createExpression(project, DEFAULT_STRING));
+              }
+            });
+          }
+        }
+      }
+    };
+  }
+}