Detect filename is not compliant with PascalCase convention

pinterest · Mar 21, 2021 · 3f81397 · 3f81397
1 parent 503b722
commit 3f81397
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -6,6 +6,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 ### Added
 ### Fixed
 ### Changed
+- Detect FilenameRule is not compliant with PascalCase convention ([#1004](https://github.com/pinterest/ktlint/pull/1117))
 ### Removed
 
 ## [0.41.0] - 2021-03-16

diff --git a/...nt-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/FilenameRule.kt b/...nt-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/FilenameRule.kt
@@ -4,6 +4,7 @@ import com.pinterest.ktlint.core.KtLint
 import com.pinterest.ktlint.core.Rule
 import com.pinterest.ktlint.core.ast.ElementType.BLOCK_COMMENT
 import com.pinterest.ktlint.core.ast.ElementType.CLASS
+import com.pinterest.ktlint.core.ast.ElementType.DOT
 import com.pinterest.ktlint.core.ast.ElementType.EOL_COMMENT
 import com.pinterest.ktlint.core.ast.ElementType.FILE_ANNOTATION_LIST
 import com.pinterest.ktlint.core.ast.ElementType.IDENTIFIER
@@ -24,17 +25,6 @@ import org.jetbrains.kotlin.com.intellij.psi.tree.IElementType
  */
 class FilenameRule : Rule("filename"), Rule.Modifier.RestrictToRoot {
 
-    private val ignoreSet = setOf<IElementType>(
-        FILE_ANNOTATION_LIST,
-        PACKAGE_DIRECTIVE,
-        IMPORT_LIST,
-        WHITE_SPACE,
-        EOL_COMMENT,
-        BLOCK_COMMENT,
-        KDOC,
-        SHEBANG_COMMENT
-    )
-
     override fun visit(
         node: ASTNode,
         autoCorrect: Boolean,
@@ -45,31 +35,60 @@ class FilenameRule : Rule("filename"), Rule.Modifier.RestrictToRoot {
             // ignore all non ".kt" files (including ".kts")
             return
         }
-        var type: String? = null
-        var className: String? = null
-        for (el in node.getChildren(null)) {
-            if (el.elementType == CLASS ||
+
+        val elements = node.getChildren(null).filterNotNull().filter { el ->
+            el.elementType == CLASS ||
                 el.elementType == OBJECT_DECLARATION ||
-                el.elementType == TYPEALIAS
-            ) {
-                if (className != null) {
-                    // more than one class/object/typealias present
-                    return
-                }
-                val id = el.findChildByType(IDENTIFIER)
-                type = id?.prevCodeSibling()?.text
-                className = id?.text
-            } else if (!ignoreSet.contains(el.elementType)) {
+                el.elementType == TYPEALIAS ||
                 // https://github.com/android/android-ktx/blob/51005889235123f41492eaaecde3c623473dfe95/src/main/java/androidx/core/graphics/Path.kt case
-                return
-            }
+                !ignoreSet.contains(el.elementType)
+        }.map { el ->
+            val id = el.findChildByType(IDENTIFIER)
+            val prevCodeSibling = id?.prevCodeSibling()
+            // in case of extension function rename DOT to fun
+            val type = if (prevCodeSibling?.elementType == DOT) "fun" else prevCodeSibling?.text ?: ""
+            val name = id?.text ?: ""
+            ResultElement(type, name)
         }
-        if (className != null) {
-            val unescapedClassName = className.replace("`", "")
-            val name = Paths.get(filePath).fileName.toString().substringBefore(".")
-            if (name != "package" && name != unescapedClassName) {
-                emit(0, "$type $className should be declared in a file named $unescapedClassName.kt", false)
+
+        val name = Paths.get(filePath).fileName.toString().substringBefore(".")
+        if (name != "package") {
+            if (elements.size == 1) {
+                val element = elements.first()
+                if (element.type != "fun") {
+                    val (type, className) = element
+                    val unescapedClassName = className.replace("`", "")
+                    if (name != unescapedClassName) {
+                        emit(0, "$type $className should be declared in a file named $unescapedClassName.kt", false)
+                        return
+                    }
+                }
+            }
+
+            // in all other cases (multiple elements, single non-class element, ...) check filename for PascalCase
+            if (!pascalCase.matches(name)) {
+                emit(0, "File name $name.kt should conform PascalCase", false)
             }
         }
     }
+
+    private data class ResultElement(
+        val type: String,
+        val name: String
+    )
+
+    companion object {
+        private val ignoreSet = setOf<IElementType>(
+            FILE_ANNOTATION_LIST,
+            PACKAGE_DIRECTIVE,
+            IMPORT_LIST,
+            WHITE_SPACE,
+            EOL_COMMENT,
+            BLOCK_COMMENT,
+            KDOC,
+            SHEBANG_COMMENT
+        )
+
+        private val pascalCase = """^[A-Z][A-Za-z0-9]*$""".toRegex()
+    }
 }
diff --git a/...uleset-standard/src/test/kotlin/com/pinterest/ktlint/ruleset/standard/FilenameRuleTest.kt b/...uleset-standard/src/test/kotlin/com/pinterest/ktlint/ruleset/standard/FilenameRuleTest.kt
@@ -103,6 +103,114 @@ class FilenameRuleTest {
         ).isEmpty()
     }
 
+    @Test
+    fun testNonMatchingMultipleElementsWithNonPascalCaseFilename() {
+        for (
+            src in listOf(
+                "class A",
+                "class `A`",
+                "data class A(val v: Int)",
+                "sealed class A",
+                "interface A",
+                "object A",
+                "enum class A {A}",
+                "typealias A = Set<Network.Node>",
+                "fun A.f() {}"
+            )
+        ) {
+            assertThat(
+                FilenameRule().lint(
+                    "foo.kt",
+                    """
+                    class Bar
+                    $src
+                    """.trimIndent(),
+                )
+            ).isEqualTo(
+                listOf(
+                    LintError(1, 1, "filename", "File name foo.kt should conform PascalCase")
+                )
+            )
+        }
+    }
+
+    @Test
+    fun testNonMatchingMultipleElementsWithNonPascalCaseFilenamex() {
+        for (
+            src in listOf(
+                "fun A.f() {}",
+                "fun f() {}"
+            )
+        ) {
+            assertThat(
+                FilenameRule().lint(
+                    "foo.kt",
+                    """
+                    $src
+                    """.trimIndent(),
+                )
+            ).isEqualTo(
+                listOf(
+                    LintError(1, 1, "filename", "File name foo.kt should conform PascalCase")
+                )
+            )
+        }
+    }
+
+    @Test
+    fun testMultipleElementsWithNonPascalCaseFilename() {
+        for (
+            src in listOf(
+                "class A",
+                "class `A`",
+                "data class A(val v: Int)",
+                "sealed class A",
+                "interface A",
+                "object A",
+                "enum class A {A}",
+                "typealias A = Set<Network.Node>",
+                "fun A.f() {}"
+            )
+        ) {
+            assertThat(
+                FilenameRule().lint(
+                    "Foo.kt",
+                    """
+                    class Bar
+                    $src
+                    """.trimIndent(),
+                )
+            ).isEmpty()
+        }
+    }
+
+    @Test
+    fun testMultipleElementsInPackageKtFile() {
+        for (
+            src in listOf(
+                "class A",
+                "class `A`",
+                "data class A(val v: Int)",
+                "sealed class A",
+                "interface A",
+                "object A",
+                "enum class A {A}",
+                "typealias A = Set<Network.Node>",
+                "fun A.f() {}"
+            )
+        ) {
+            assertThat(
+                FilenameRule().lint(
+                    "package.kt",
+                    """
+                    class Bar
+                    $src
+                    """.trimIndent(),
+                )
+            ).isEmpty()
+        }
+    }
+
     @Test
     fun testMultipleNonTopLevelClasses() {
         assertThat(