Fix VIM-2656: Incorrect shift motion behavior with tabs

tests/java-tests/src/test/kotlin/org/jetbrains/plugins/ideavim/action/change/shift/ShiftRightTabsTest.kt

@@ -0,0 +1,124 @@
+/*
+ * Copyright 2003-2024 The IdeaVim authors
+ *
+ * Use of this source code is governed by an MIT-style
+ * license that can be found in the LICENSE.txt file or at
+ * https://opensource.org/licenses/MIT.
+ */
+
+package org.jetbrains.plugins.ideavim.action.change.shift
+
+import com.intellij.application.options.CodeStyle
+import com.intellij.ide.highlighter.JavaFileType
+import org.jetbrains.plugins.ideavim.SkipNeovimReason
+import org.jetbrains.plugins.ideavim.TestWithoutNeovim
+import org.jetbrains.plugins.ideavim.VimJavaTestCase
+import org.junit.jupiter.api.Test
+
+/**
+ * Tests for VIM-2656: Incorrect shift motion behavior with tabs
+ */
+class ShiftRightTabsTest : VimJavaTestCase() {
+  @TestWithoutNeovim(SkipNeovimReason.NOT_VIM_TESTING)
+  @Test
+  fun `test shift right with tabs should add full tab`() {
+    val before = """
+      |public class C {
+      |.${c}println("hello");
+      |}
+    """.trimMargin().dotToTab()
+
+    val after = """
+      |public class C {
+      |..println("hello");
+      |}
+    """.trimMargin().dotToTab()
+
+    usingTabs {
+      configureByJavaText(before)
+      typeText(">>")
+      assertState(after)
+    }
+  }
+
+  @TestWithoutNeovim(SkipNeovimReason.NOT_VIM_TESTING)
+  @Test
+  fun `test shift right with tabs from no indent`() {
+    val before = """
+      |public class C {
+      |${c}println("hello");
+      |}
+    """.trimMargin()
+
+    val after = """
+      |public class C {
+      |.println("hello");
+      |}
+    """.trimMargin().dotToTab()
+
+    usingTabs {
+      configureByJavaText(before)
+      typeText(">>")
+      assertState(after)
+    }
+  }
+
+  @TestWithoutNeovim(SkipNeovimReason.NOT_VIM_TESTING)
+  @Test
+  fun `test shift right multiple times with tabs`() {
+    val before = """
+      |public class C {
+      |${c}println("hello");
+      |}
+    """.trimMargin()
+
+    val after = """
+      |public class C {
+      |...println("hello");
+      |}
+    """.trimMargin().dotToTab()
+
+    usingTabs {
+      configureByJavaText(before)
+      typeText(">>".repeat(3))
+      assertState(after)
+    }
+  }
+
+  @TestWithoutNeovim(SkipNeovimReason.NOT_VIM_TESTING)
+  @Test
+  fun `test shift right with existing misaligned spaces should use full tabs`() {
+    // VIM-2656: Starting with 2 spaces, >> should result in full tab indent, not mixed
+    val before = """
+      |public class C {
+      |  ${c}println("hello");
+      |}
+    """.trimMargin()
+
+    val after = """
+      |public class C {
+      |.println("hello");
+      |}
+    """.trimMargin().dotToTab()
+
+    usingTabs {
+      configureByJavaText(before)
+      typeText(">>")
+      assertState(after)
+    }
+  }
+
+  private fun usingTabs(action: () -> Unit) {
+    val testSettings = CodeStyle.createTestSettings()
+    val javaSettings = testSettings.getIndentOptions(JavaFileType.INSTANCE)
+    javaSettings.USE_TAB_CHARACTER = true
+    javaSettings.TAB_SIZE = 4
+    javaSettings.INDENT_SIZE = 4
+    CodeStyle.setTemporarySettings(fixture.project, testSettings)
+    try {
+      action()
+    } finally {
+      CodeStyle.dropTemporarySettings(fixture.project)
+    }
+  }
+}

vim-engine/src/main/kotlin/com/maddyhome/idea/vim/api/VimChangeGroupBase.kt

@@ -1998,15 +1998,18 @@ abstract class VimChangeGroupBase : VimChangeGroup {
       }
     } else {
       // Shift non-blockwise selection
+      val indentSize = indentConfig.getIndentSize(1)
       for (l in sline..eline) {
         val soff = editor.getLineStartOffset(l)
         val eoff = editor.getLineEndOffset(l, true)
         val woff = injector.motion.moveCaretToLineStartSkipLeading(editor, l)
         val col = editor.offsetToBufferPosition(woff).column
-        val limit = max(0.0, (col + dir * indentConfig.getIndentSize(count)).toDouble())
-          .toInt()
+        // Calculate the current indent depth (floor division)
+        val currentDepth = col / indentSize
+        // Calculate the new depth after shifting
+        val newDepth = max(0, currentDepth + dir * count)
         if (col > 0 || soff != eoff) {
-          val indent = indentConfig.createIndentBySize(limit)
+          val indent = indentConfig.createIndentByDepth(newDepth)
           replaceText(editor, caret, soff, woff, indent)
         }
       }