Improve MultilineRawStringIndentation

detekt-rules-style/src/main/kotlin/io/gitlab/arturbosch/detekt/rules/style/MultilineRawStringIndentation.kt

@@ -67,7 +67,16 @@ class MultilineRawStringIndentation(config: Config) : Rule(config) {
         val lineCount = text.lines().count()
         if (lineCount <= 1) return
         if (!expression.isTrimmed()) return
-        if (!text.matches(rawStringRegex)) return
+        if (!text.matches(rawStringRegex)) {
+            report(
+                CodeSmell(
+                    issue,
+                    Entity.from(expression),
+                    "A multiline raw string should start with a break line and should end with another",
+                )
+            )
+            return
+        }
 
         val lineAndColumn = getLineAndColumnInPsiFile(expression.containingFile, expression.textRange) ?: return
 
@@ -158,7 +167,7 @@ private fun message(desiredIntent: Int, currentIndent: Int): String {
     return "The indentation should be $desiredIntent but it is $currentIndent."
 }
 
-private val rawStringRegex = "\"{3}\n.*\n *\"{3}".toRegex(RegexOption.DOT_MATCHES_ALL)
+private val rawStringRegex = "\"{3}\n(.*\n)? *\"{3}".toRegex(RegexOption.DOT_MATCHES_ALL)
 
 private fun String.countIndent() = this.takeWhile { it == ' ' }.count()
 

detekt-rules-style/src/test/kotlin/io/gitlab/arturbosch/detekt/rules/style/MultilineRawStringIndentationSpec.kt

@@ -301,38 +301,66 @@ class MultilineRawStringIndentationSpec {
         }
 
         @Test
-        fun `don't raise if it contains content after the opening triple quote`() {
+        fun `don't raise if it isEmpty`() {
             val code = """
-                val a = ${TQ}Hello world!
-                    How are you?
+                val a = $TQ
                 $TQ.trimIndent()
             """.trimIndent()
             subject.compileAndLint(code)
             assertThat(subject.findings)
                 .isEmpty()
         }
+    }
+
+    @Nested
+    inner class MissingBreakingLine {
 
         @Test
-        fun `don't raise if it contains content before the closing triple quote`() {
+        fun `raise missing break line start`() {
+            val code = """
+                val a = ${TQ}Hello world!
+                    Hola mundo!
+                $TQ.trimIndent()
+            """.trimIndent()
+            subject.compileAndLint(code)
+            assertThat(subject.findings)
+                .hasSize(1)
+        }
+
+        @Test
+        fun `raise missing break line end`() {
             val code = """
                 val a = $TQ
                     Hello world!
-                    How are you?$TQ.trimIndent()
+                    Hola mundo!$TQ.trimIndent()
             """.trimIndent()
             subject.compileAndLint(code)
             assertThat(subject.findings)
-                .isEmpty()
+                .hasSize(1)
         }
 
         @Test
-        fun `don't raise if it isEmpty`() {
+        fun `raise missing break line both`() {
+            val code = """
+                val a = ${TQ}Hello world!
+                    Hola mundo!$TQ.trimIndent()
+            """.trimIndent()
+            subject.compileAndLint(code)
+            assertThat(subject.findings)
+                .hasSize(1)
+        }
+
+        @Test
+        fun `don't raise multiline raw string when correct`() {
             val code = """
                 val a = $TQ
+                    Hello world!
+                    Hola mundo!
                 $TQ.trimIndent()
             """.trimIndent()
             subject.compileAndLint(code)
             assertThat(subject.findings)
-                .isEmpty()
+                .hasSize(0)
         }
     }
 }