RegExp: new "Begin or end anchor in unexpected position" inspection

2026-09-27 10:03:11 +07:00 · 2018-01-03 17:51:13 +01:00
parent d4414dc4ee
commit 77426f343a
4 changed files with 158 additions and 0 deletions
@@ -54,5 +54,8 @@
    <localInspection groupName="RegExp" language="RegExp" shortName="RegExpRedundantEscape"
                     displayName="Redundant character escape" enabledByDefault="true" level="WARNING"
                     implementationClass="org.intellij.lang.regexp.inspection.RedundantEscapeInspection"/>
+    <localInspection groupName="RegExp" language="RegExp" shortName="RegExpUnexpectedAnchor"
+                     displayName="Begin or end anchor in unexpected position" enabledByDefault="true" level="WARNING"
+                     implementationClass="org.intellij.lang.regexp.inspection.UnexpectedAnchorInspection"/>
  </extensions>
 </idea-plugin>
@@ -0,0 +1,11 @@
+<html>
+<body>
+Reports <code>^</code> or <code>\A</code> anchors not at the beginning of the pattern and
+<code>$</code>, <code>\Z</code> or <code>\z</code> anchors not at the end of the pattern.
+In the wrong position these RegExp anchors prevent the pattern from matching anything.
+In case of the <code>^</code> and <code>$</code> anchors, most likely the literal character was meant and the escape forgotten.
+<!-- tooltip end -->
+<p>
+<small>New in 2018.1</small>
+</body>
+</html>
@@ -0,0 +1,101 @@
+/*
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+ */
+package org.intellij.lang.regexp.inspection;
+
+import com.intellij.codeInspection.LocalInspectionTool;
+import com.intellij.codeInspection.ProblemsHolder;
+import com.intellij.psi.PsiComment;
+import com.intellij.psi.PsiElement;
+import com.intellij.psi.PsiElementVisitor;
+import com.intellij.psi.PsiWhiteSpace;
+import com.intellij.psi.util.PsiTreeUtil;
+import org.intellij.lang.regexp.psi.*;
+import org.jetbrains.annotations.Nls;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * @author Bas Leijdekkers
+ */
+public class UnexpectedAnchorInspection extends LocalInspectionTool {
+
+  @Nls
+  @NotNull
+  @Override
+  public String getDisplayName() {
+    return "Begin or end anchor in unexpected position";
+  }
+
+  @NotNull
+  @Override
+  public PsiElementVisitor buildVisitor(@NotNull ProblemsHolder holder, boolean isOnTheFly) {
+    return new UnexpectedAnchorVisitor(holder);
+  }
+
+  private static class UnexpectedAnchorVisitor extends RegExpElementVisitor {
+
+    private final ProblemsHolder myHolder;
+
+    public UnexpectedAnchorVisitor(ProblemsHolder holder) {
+      myHolder = holder;
+    }
+
+    @Override
+    public void visitRegExpBoundary(RegExpBoundary boundary) {
+      super.visitRegExpBoundary(boundary);
+      final RegExpBoundary.Type type = boundary.getType();
+      switch (type) {
+        case BEGIN: // \A
+          if (!hasUnexpectedSibling(boundary, false, false)) return;
+          break;
+        case LINE_START: // ^
+          if (!hasUnexpectedSibling(boundary, false, true)) return;
+          break;
+        case END: // \z
+        case END_NO_LINE_TERM: // \Z
+          if (!hasUnexpectedSibling(boundary, true, false)) return;
+        break;
+        case LINE_END: // $
+          if (!hasUnexpectedSibling(boundary, true, true)) return;
+          break;
+        default:
+          return;
+      }
+      myHolder.registerProblem(boundary, "Anchor <code>#ref</code> in unexpected position");
+    }
+
+    private static boolean hasUnexpectedSibling(PsiElement element, boolean next, boolean line) {
+      PsiElement sibling = next
+                           ? PsiTreeUtil.skipSiblingsForward(element, PsiComment.class, PsiWhiteSpace.class, RegExpSetOptions.class)
+                           : PsiTreeUtil.skipSiblingsBackward(element, PsiComment.class, PsiWhiteSpace.class, RegExpSetOptions.class);
+      if (sibling == null) {
+        return false;
+      }
+      if (line) {
+        if (sibling instanceof RegExpChar) {
+          final int value = ((RegExpChar)sibling).getValue();
+          return value != '\n' && value != '\r';
+        }
+        else if (sibling instanceof RegExpSimpleClass) {
+          final RegExpSimpleClass.Kind kind = ((RegExpSimpleClass)sibling).getKind();
+          switch (kind) {
+            case ANY:
+            case NON_DIGIT:
+            case NON_WORD:
+            case SPACE:
+            case NON_HORIZONTAL_SPACE:
+            case NON_VERTICAL_SPACE:
+            case NON_XML_NAME_START:
+            case NON_XML_NAME_PART:
+            case UNICODE_LINEBREAK:
+              return false;
+            default:
+              return true;
+          }
+        }
+        return sibling instanceof RegExpBoundary;
+      }
+      return true;
+    }
+  }
+}
@@ -0,0 +1,43 @@
+/*
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+ */
+package org.intellij.lang.regexp.inspection;
+
+import com.intellij.codeInspection.LocalInspectionTool;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * @author Bas Leijdekkers
+ */
+@SuppressWarnings("RegExpUnexpectedAnchor")
+public class UnexpectedAnchorInspectionTest extends RegExpInspectionTestCase {
+
+  public void testSimple() {
+    highlightTest("<warning descr=\"Anchor '$' in unexpected position\">$</warning><warning descr=\"Anchor '^' in unexpected position\">^</warning>");
+  }
+
+  public void testAZ() {
+    highlightTest("\n<warning descr=\"Anchor '\\A' in unexpected position\">\\A</warning><warning descr=\"Anchor '\\Z' in unexpected position\">\\Z</warning>\n");
+  }
+
+  public void testNoWarn() {
+    highlightTest("^$");
+    highlightTest("\n^$\n");
+  }
+
+  public void testCommentMode() {
+    highlightTest("(?x)\n" +
+                  "# comment\n" +
+                  "^impedance");
+  }
+
+  public void testIDEA184428() {
+    highlightTest("\\(\\s*<=\\s*;\\s*`<warning descr=\"Anchor '$' in unexpected position\">$</warning>\"SeqNo\"\\s*;\\s*-?\\d+j\\s*\\)s");
+  }
+
+  @NotNull
+  @Override
+  protected LocalInspectionTool getInspection() {
+    return new UnexpectedAnchorInspection();
+  }
+}