com.pinterest.ktlint.ruleset.standard.rules.NoUnusedImportsRule.kt Maven / Gradle / Ivy
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An anti-bikeshedding Kotlin linter with built-in formatter.
package com.pinterest.ktlint.ruleset.standard.rules
import com.pinterest.ktlint.rule.engine.core.api.ElementType.BY_KEYWORD
import com.pinterest.ktlint.rule.engine.core.api.ElementType.DOT_QUALIFIED_EXPRESSION
import com.pinterest.ktlint.rule.engine.core.api.ElementType.FILE
import com.pinterest.ktlint.rule.engine.core.api.ElementType.IDENTIFIER
import com.pinterest.ktlint.rule.engine.core.api.ElementType.IMPORT_DIRECTIVE
import com.pinterest.ktlint.rule.engine.core.api.ElementType.OPERATION_REFERENCE
import com.pinterest.ktlint.rule.engine.core.api.ElementType.PACKAGE_DIRECTIVE
import com.pinterest.ktlint.rule.engine.core.api.ElementType.REFERENCE_EXPRESSION
import com.pinterest.ktlint.rule.engine.core.api.RuleId
import com.pinterest.ktlint.rule.engine.core.api.isPartOf
import com.pinterest.ktlint.rule.engine.core.api.isRoot
import com.pinterest.ktlint.rule.engine.core.api.isWhiteSpaceWithNewline
import com.pinterest.ktlint.rule.engine.core.api.lastChildLeafOrSelf
import com.pinterest.ktlint.rule.engine.core.api.nextLeaf
import com.pinterest.ktlint.rule.engine.core.api.nextSibling
import com.pinterest.ktlint.rule.engine.core.api.prevLeaf
import com.pinterest.ktlint.rule.engine.core.api.prevSibling
import com.pinterest.ktlint.rule.engine.core.util.safeAs
import com.pinterest.ktlint.ruleset.standard.StandardRule
import org.jetbrains.kotlin.com.intellij.lang.ASTNode
import org.jetbrains.kotlin.com.intellij.psi.PsiElement
import org.jetbrains.kotlin.com.intellij.psi.impl.source.tree.CompositeElement
import org.jetbrains.kotlin.com.intellij.psi.impl.source.tree.LeafElement
import org.jetbrains.kotlin.kdoc.lexer.KDocTokens.MARKDOWN_LINK
import org.jetbrains.kotlin.kdoc.psi.impl.KDocLink
import org.jetbrains.kotlin.psi.KtCallExpression
import org.jetbrains.kotlin.psi.KtDotQualifiedExpression
import org.jetbrains.kotlin.psi.KtImportDirective
import org.jetbrains.kotlin.psi.KtPackageDirective
import org.jetbrains.kotlin.resolve.ImportPath
public class NoUnusedImportsRule : StandardRule("no-unused-imports") {
private val ref =
mutableSetOf(
Reference("*", false),
)
private val parentExpressions = mutableSetOf()
private val imports = mutableMapOf()
private var packageName = ""
private var rootNode: ASTNode? = null
private var foundByKeyword = false
override fun beforeVisitChildNodes(
node: ASTNode,
autoCorrect: Boolean,
emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> Unit,
) {
if (node.isRoot()) {
rootNode = node
}
when (node.elementType) {
PACKAGE_DIRECTIVE -> {
val packageDirective = node.psi as KtPackageDirective
packageName = packageDirective.qualifiedName
}
IMPORT_DIRECTIVE -> {
val importPath = (node.psi as KtImportDirective).importPath!!
if (imports.containsKey(importPath)) {
// Emit directly when same import occurs more than once
emit(node.startOffset, "Unused import", true)
if (autoCorrect) {
node.psi.delete()
}
} else {
imports[importPath] = node
}
}
DOT_QUALIFIED_EXPRESSION -> {
if (node.isExpressionForStaticImportWithExistingParentImport()) {
parentExpressions.add(node.text.substringBeforeLast("("))
}
}
MARKDOWN_LINK -> {
node
.psi
.safeAs()
?.let { kdocLink ->
val linkText = kdocLink.getLinkText().removeBackticksAndTrim()
ref.add(Reference(linkText.split('.').first(), false))
ref.add(Reference(linkText.split('.').last(), false))
}
}
REFERENCE_EXPRESSION, OPERATION_REFERENCE -> {
if (!node.isPartOf(IMPORT_DIRECTIVE)) {
val identifier =
if (node is CompositeElement) {
node.findChildByType(IDENTIFIER)
} else {
node
}
identifier
?.let { identifier.text }
?.takeIf { it.isNotBlank() }
?.let {
ref.add(
Reference(
it.removeBackticksAndTrim(),
node.psi.parentDotQualifiedExpression() != null,
),
)
}
}
}
BY_KEYWORD -> foundByKeyword = true
}
}
override fun afterVisitChildNodes(
node: ASTNode,
autoCorrect: Boolean,
emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> Unit,
) {
if (node.elementType == FILE) {
val directCalls = ref.filter { !it.inDotQualifiedExpression }.map { it.text }
parentExpressions.forEach { parent ->
imports
.filterKeys { import ->
val importPath = import.pathStr.removeBackticksAndTrim()
importPath.endsWith(".$parent") && directCalls.none { importPath.endsWith(".$it") }
}.forEach { (importPath, importNode) ->
emit(importNode.startOffset, "Unused import", true)
if (autoCorrect) {
imports.remove(importPath, importNode)
importNode.removeImportDirective()
}
}
}
imports.forEach { (_, node) ->
val importDirective = node.psi as KtImportDirective
val name = importDirective.importPath?.importedName?.asString()?.removeBackticksAndTrim()
val importPath = importDirective.importPath?.pathStr?.removeBackticksAndTrim()!!
if (importDirective.aliasName == null &&
(packageName.isEmpty() || importPath.startsWith("$packageName.")) &&
importPath.substring(packageName.length + 1).indexOf('.') == -1
) {
emit(node.startOffset, "Unnecessary import", true)
if (autoCorrect) {
importDirective.delete()
}
} else if (name != null && (!ref.map { it.text }.contains(name) || !isAValidImport(importPath)) &&
!OPERATOR_SET.contains(name) &&
!name.isComponentN() &&
!importPath.ignoreProvideDelegate()
) {
emit(node.startOffset, "Unused import", true)
if (autoCorrect) {
val nextSibling = node.nextSibling()
if (nextSibling == null) {
// Last import
node
.lastChildLeafOrSelf()
.nextLeaf()
?.takeIf { it.isWhiteSpaceWithNewline() }
?.let { whitespace ->
if (node.prevLeaf() == null) {
// Also it was the first import, and it is not preceded by any other node containing some text. So
// all whitespace until the next is redundant
whitespace.treeParent.removeChild(whitespace)
} else {
val textAfterFirstNewline =
whitespace.text
.substringAfter("\n")
if (textAfterFirstNewline.isNotBlank()) {
(whitespace as LeafElement).rawReplaceWithText(textAfterFirstNewline)
}
}
}
} else {
nextSibling
.takeIf { it.isWhiteSpaceWithNewline() }
?.let { whitespace ->
whitespace.treeParent.removeChild(whitespace)
}
}
importDirective.delete()
}
}
}
}
}
private fun String.ignoreProvideDelegate() =
if (endsWith(".provideDelegate")) {
// Ignore provideDelegate if the `by` keyword is found anywhere in the file
foundByKeyword
} else {
false
}
private fun ASTNode.removeImportDirective() {
require(this.elementType == IMPORT_DIRECTIVE)
when {
treeParent.firstChildNode == this -> {
nextSibling()
?.takeIf { it.isWhiteSpaceWithNewline() }
?.let { it.treeParent.removeChild(it) }
}
treeParent.lastChildNode == this -> {
prevSibling()
?.takeIf { it.isWhiteSpaceWithNewline() }
?.let { it.treeParent.removeChild(it) }
}
else -> {
nextLeaf(true)
?.takeIf { it.isWhiteSpaceWithNewline() }
?.let { it.treeParent.removeChild(it) }
}
}
treeParent.removeChild(this)
}
private fun ASTNode.isExpressionForStaticImportWithExistingParentImport(): Boolean {
if (!containsMethodCall()) {
return false
}
val methodCallExpression = text.substringBeforeLast("(")
// Only check static imports; identified if they start with a capital letter indicating a
// class name rather than a sub-package
if (methodCallExpression.isNotEmpty() && methodCallExpression[0] !in 'A'..'Z') {
return false
}
imports
.filterKeys { it.pathStr.removeBackticksAndTrim().endsWith(".$methodCallExpression") }
.forEach { import ->
val count =
imports.count {
it.key.pathStr.removeBackticksAndTrim().startsWith(
import.key.pathStr.removeBackticksAndTrim().substringBefore(methodCallExpression),
)
}
// Parent import and static import both are present
if (count > 1) {
return true
}
}
return false
}
private fun ASTNode.containsMethodCall() = text.split(".").last().contains("(")
// Check if the import being checked is present in the filtered import list
private fun isAValidImport(importPath: String) =
imports.any {
it.key.pathStr.removeBackticksAndTrim().contains(importPath)
}
private fun String.isComponentN() = COMPONENT_N_REGEX.matches(this)
private fun PsiElement.parentDotQualifiedExpression(): KtDotQualifiedExpression? {
val callOrThis = (parent as? KtCallExpression)?.takeIf { it.calleeExpression == this } ?: this
return (callOrThis.parent as? KtDotQualifiedExpression)?.takeIf { it.selectorExpression == callOrThis }
}
private fun String.removeBackticksAndTrim() = replace("`", "").trim()
private data class Reference(val text: String, val inDotQualifiedExpression: Boolean)
private companion object {
val COMPONENT_N_REGEX = Regex("^component\\d+$")
val OPERATOR_SET =
setOf(
// unary
"unaryPlus", "unaryMinus", "not",
// inc/dec
"inc", "dec",
// arithmetic
"plus", "minus", "times", "div", "rem", "mod", "rangeTo",
// in
"contains",
// indexed access
"get", "set",
// invoke
"invoke",
// augmented assignments
"plusAssign", "minusAssign", "timesAssign", "divAssign", "modAssign",
// (in)equality
"equals",
// comparison
"compareTo",
// iteration (https://github.com/shyiko/ktlint/issues/40)
"iterator",
// by (https://github.com/shyiko/ktlint/issues/54)
"getValue", "setValue",
)
}
}
public val NO_UNUSED_IMPORTS_RULE_ID: RuleId = NoUnusedImportsRule().ruleId
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