Remove empty spans rendering for missed modifiers (#3343)

* Remove property modifiers if there are none
* Remove variance modifier rendering if it is absent

2 files changed, 67 insertions, 5 deletions

diff --git a/dokka-subprojects/plugin-base/src/main/kotlin/org/jetbrains/dokka/base/signatures/KotlinSignatureProvider.kt b/dokka-subprojects/plugin-base/src/main/kotlin/org/jetbrains/dokka/base/signatures/KotlinSignatureProvider.kt
index 2180e776..0fc7ca72 100644
--- a/dokka-subprojects/plugin-base/src/main/kotlin/org/jetbrains/dokka/base/signatures/KotlinSignatureProvider.kt
+++ b/dokka-subprojects/plugin-base/src/main/kotlin/org/jetbrains/dokka/base/signatures/KotlinSignatureProvider.kt
@@ -248,7 +248,7 @@ public class KotlinSignatureProvider(
                 p.modifier[sourceSet].takeIf { it !in ignoredModifiers }?.let {
                         if (it is JavaModifier.Empty) KotlinModifier.Open else it
                     }?.name?.let { keyword("$it ") }
-                p.modifiers()[sourceSet]?.toSignatureString()?.let { keyword(it) }
+                p.modifiers()[sourceSet]?.toSignatureString()?.takeIf { it.isNotEmpty() }?.let { keyword(it) }
                 if (p.isMutable()) keyword("var ") else keyword("val ")
                 list(p.generics, prefix = "<", suffix = "> ",
                     separatorStyles = mainStyles + TokenStyle.Punctuation,
@@ -303,7 +303,7 @@ public class KotlinSignatureProvider(
                     f.modifier[sourceSet]?.takeIf { it !in ignoredModifiers }?.let {
                         if (it is JavaModifier.Empty) KotlinModifier.Open else it
                     }?.name?.let { keyword("$it ") }
-                    f.modifiers()[sourceSet]?.toSignatureString()?.let { keyword(it) }
+                    f.modifiers()[sourceSet]?.toSignatureString()?.takeIf { it.isNotEmpty() }?.let { keyword(it) }
                     keyword("fun ")
                     list(
                         f.generics, prefix = "<", suffix = "> ",
@@ -434,7 +434,7 @@ public class KotlinSignatureProvider(
                 }
 
             is Variance<*> -> group(styles = emptySet()) {
-                keyword("$p ".takeIf { it.isNotBlank() } ?: "")
+                p.takeIf { it.toString().isNotEmpty() }?.let { keyword("$it ") }
                 signatureForProjection(p.inner, showFullyQualifiedName)
             }
 
diff --git a/dokka-subprojects/plugin-base/src/test/kotlin/signatures/SignatureTest.kt b/dokka-subprojects/plugin-base/src/test/kotlin/signatures/SignatureTest.kt
index 80a043fe..3099400e 100644
--- a/dokka-subprojects/plugin-base/src/test/kotlin/signatures/SignatureTest.kt
+++ b/dokka-subprojects/plugin-base/src/test/kotlin/signatures/SignatureTest.kt
@@ -198,6 +198,27 @@ class SignatureTest : BaseAbstractTest() {
     }
 
     @Test
+    fun `fun with use site variance modifier in`() {
+        val source = source("fun simpleFun(params: Array<in String>): Unit")
+        val writerPlugin = TestOutputWriterPlugin()
+
+        testInline(
+            source,
+            configuration,
+            pluginOverrides = listOf(writerPlugin)
+        ) {
+            renderingStage = { _, _ ->
+                writerPlugin.writer.renderedContent("root/example/simple-fun.html").firstSignature().match(
+                    "fun ", A("simpleFun"), "(", Parameters(
+                        Parameter("params: ", A("Array"), "<in ", A("String"), ">"),
+                    ), ")",
+                    ignoreSpanWithTokenStyle = true
+                )
+            }
+        }
+    }
+
+    @Test
     fun `fun with definitely non-nullable types`() {
         val source = source("fun <T> elvisLike(x: T, y: T & Any): T & Any = x ?: y")
         val writerPlugin = TestOutputWriterPlugin()
@@ -313,6 +334,48 @@ class SignatureTest : BaseAbstractTest() {
     }
 
     @Test
+    fun `class with declaration site variance modifier`() {
+        val writerPlugin = TestOutputWriterPlugin()
+
+        testInline(
+            """
+                |/src/main/kotlin/common/Test.kt
+                |package example
+                |
+                |class PrimaryConstructorClass<out T> { }
+            """.trimMargin(),
+            configuration,
+            pluginOverrides = listOf(writerPlugin)
+        ) {
+            renderingStage = { _, _ ->
+                writerPlugin.writer.renderedContent("root/example/-primary-constructor-class/index.html").firstSignature().match(
+                    Span("class "), A("PrimaryConstructorClass"), Span("<"), Span("out "), A("T"), Span(">"),
+                )
+            }
+        }
+    }
+
+    @Test
+    fun `constructor property on class page`() {
+        val source = source("data class DataClass(val arg: String)")
+        val writerPlugin = TestOutputWriterPlugin()
+
+        testInline(
+            source,
+            configuration,
+            pluginOverrides = listOf(writerPlugin)
+        ) {
+            renderingStage = { _, _ ->
+                assertEquals(
+                    writerPlugin.writer.renderedContent("root/example/-data-class/index.html").lastSignature().html(),
+                    "<span class=\"token keyword\">val </span><a href=\"arg.html\">arg</a><span class=\"token operator\">: </span><a href=\"https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-string/index.html\">String</a>"
+
+                )
+            }
+        }
+    }
+
+    @Test
     fun `functional interface`() {
         val source = source("fun interface KRunnable")
         val writerPlugin = TestOutputWriterPlugin()
@@ -896,8 +959,7 @@ class SignatureTest : BaseAbstractTest() {
         ) {
             renderingStage = { _, _ ->
                 writerPlugin.writer.renderedContent("root/example/-primary-constructor-class/index.html").firstSignature().match(
-                    // In `<T>` expression, an empty `<span class="token keyword"></span>` is present for some reason
-                    Span("class "), A("PrimaryConstructorClass"), Span("<"), Span(), A("T"), Span(">"), Span("("), Parameters(
+                    Span("class "), A("PrimaryConstructorClass"), Span("<"), A("T"), Span(">"), Span("("), Parameters(
                         Parameter(Span("val "), "x", Span(": "), A("Int"), Span(",")),
                         Parameter(Span("var "), "s", Span(": "), A("String"))
                     ), Span(")"),