Warning for domain name (#696)

* Warning for domain name

### What's done:
Handled case when domainName is empty in config

diktat-common/src/main/kotlin/org/cqfn/diktat/common/config/rules/RulesConfigReader.kt

@@ -112,8 +112,8 @@ data class CommonConfiguration(private val configuration: Map<String, String>?)
     /**
      * Start of package name, which shoould be common, e.g. org.example.myproject
      */
-    val domainName: String by lazy {
-        (configuration ?: emptyMap()).getOrDefault("domainName", "")
+    val domainName: String? by lazy {
+        configuration?.get("domainName")
     }
 
     /**

diktat-rules/src/main/kotlin/org/cqfn/diktat/ruleset/rules/PackageNaming.kt

@@ -33,7 +33,7 @@ import java.util.concurrent.atomic.AtomicInteger
  * need to support autofixing of directories in the same way as package is named. For example if we have package name:
  * package a.b.c.D -> then class D should be placed in a/b/c/ directories
  */
-@Suppress("ForbiddenComment")
+@Suppress("ForbiddenComment", "TOO_MANY_LINES_IN_LAMBDA")
 class PackageNaming(private val configRules: List<RulesConfig>) : Rule("package-naming") {
     private var isFixMode: Boolean = false
     private lateinit var emitWarn: EmitType
@@ -46,32 +46,30 @@ class PackageNaming(private val configRules: List<RulesConfig>) : Rule("package-
         emitWarn = emit
 
         val configuration by configRules.getCommonConfiguration()
-        domainName = configuration.also {
-            if (it.isDefault && visitorCounter.incrementAndGet() == 1) {
-                log.error("Not able to find an external configuration for domain name in the common" +
-                        " configuration (is it missing in yml config?)")
-            }
-        }
-            .domainName
+        configuration.domainName?.let {
+            domainName = it
+            if (node.elementType == PACKAGE_DIRECTIVE) {
+                val filePath = node.getRootNode().getFilePath()
+                // calculating package name based on the directory where the file is placed
+                val realPackageName = calculateRealPackageName(filePath)
+
+                // if node isLeaf - this means that there is no package name declared
+                if (node.isLeaf() && !filePath.isKotlinScript()) {
+                    warnAndFixMissingPackageName(node, realPackageName, filePath)
+                    return
+                }
 
-        if (node.elementType == PACKAGE_DIRECTIVE) {
-            val filePath = node.getRootNode().getFilePath()
-            // calculating package name based on the directory where the file is placed
-            val realPackageName = calculateRealPackageName(filePath)
+                // getting all identifiers from existing package name into the list like [org, diktat, project]
+                val wordsInPackageName = node.findAllNodesWithSpecificType(IDENTIFIER)
 
-            // if node isLeaf - this means that there is no package name declared
-            if (node.isLeaf() && !filePath.isKotlinScript()) {
-                warnAndFixMissingPackageName(node, realPackageName, filePath)
-                return
+                // no need to check that packageIdentifiers is empty, because in this case parsing will fail
+                checkPackageName(wordsInPackageName, node)
+                // fix in checkFilePathMatchesWithPackageName is much more aggressive than fixes in checkPackageName, they can conflict
+                checkFilePathMatchesWithPackageName(wordsInPackageName, realPackageName, node)
             }
-
-            // getting all identifiers from existing package name into the list like [org, diktat, project]
-            val wordsInPackageName = node.findAllNodesWithSpecificType(IDENTIFIER)
-
-            // no need to check that packageIdentifiers is empty, because in this case parsing will fail
-            checkPackageName(wordsInPackageName, node)
-            // fix in checkFilePathMatchesWithPackageName is much more aggressive than fixes in checkPackageName, they can conflict
-            checkFilePathMatchesWithPackageName(wordsInPackageName, realPackageName, node)
+        } ?: if (visitorCounter.incrementAndGet() == 1) {
+            log.error("Not able to find an external configuration for domain" +
+                    " name in the common configuration (is it missing in yml config?)")
         }
     }
 

diktat-rules/src/main/kotlin/org/cqfn/diktat/ruleset/rules/files/FileStructureRule.kt

@@ -263,21 +263,23 @@ class FileStructureRule(private val configRules: List<RulesConfig>) : Rule("file
         else -> (headerKdoc ?: copyrightComment) to firstCodeNode
     }
 
-    @Suppress("TYPE_ALIAS")
+    @Suppress("TYPE_ALIAS", "UnsafeCallOnNullableType")
     private fun regroupImports(imports: List<KtImportDirective>): List<List<KtImportDirective>> {
         val (android, notAndroid) = imports.partition {
             it.isStandard(StandardPlatforms.ANDROID)
         }
 
-        val (ownDomain, tmp) = notAndroid.partition { import ->
-            import
-                .importPath
-                ?.fqName
-                ?.pathSegments()
-                ?.zip(domainName.split(PACKAGE_SEPARATOR).map(Name::identifier))
-                ?.all { it.first == it.second }
-                ?: false
-        }
+        val (ownDomain, tmp) = domainName?.let {
+            notAndroid.partition { import ->
+                import
+                    .importPath
+                    ?.fqName
+                    ?.pathSegments()
+                    ?.zip(it.split(PACKAGE_SEPARATOR).map(Name::identifier))
+                    ?.all { it.first == it.second }
+                    ?: false
+            }
+        } ?: Pair(emptyList(), notAndroid)
 
         val (others, javaAndKotlin) = tmp.partition {
             !it.isStandard(StandardPlatforms.JAVA) && !it.isStandard(StandardPlatforms.KOTLIN)

diktat-rules/src/test/kotlin/org/cqfn/diktat/ruleset/chapter1/PackageNamingWarnTest.kt

@@ -22,6 +22,9 @@ class PackageNamingWarnTest : LintTestBase(::PackageNaming) {
     private val rulesConfigList: List<RulesConfig> = listOf(
         RulesConfig("DIKTAT_COMMON", true, mapOf("domainName" to "org.cqfn.diktat"))
     )
+    private val rulesConfigListEmptyDomainName: List<RulesConfig> = listOf(
+        RulesConfig("DIKTAT_COMMON", true, mapOf("domainName" to ""))
+    )
 
     @Test
     @Tag(WarningNames.PACKAGE_NAME_MISSING)
@@ -229,4 +232,18 @@ class PackageNamingWarnTest : LintTestBase(::PackageNaming) {
             rulesConfigList = rulesConfigList
         )
     }
+
+    @Test
+    @Tag(WarningNames.PACKAGE_NAME_INCORRECT_PATH)
+    fun `should warn if there is empty domain name`() {
+        lintMethod(
+            """
+                |package org.cqfn.diktat
+            """.trimMargin(),
+            LintError(1, 9, ruleId, "${PACKAGE_NAME_INCORRECT_PREFIX.warnText()} ", true),
+            LintError(1, 9, ruleId, "${PACKAGE_NAME_INCORRECT_PATH.warnText()} org.cqfn.diktat.example", true),
+            fileName = "/home/testu/project/src/main/kotlin/org/cqfn/diktat/example/Example.kt",
+            rulesConfigList = rulesConfigListEmptyDomainName
+        )
+    }
 }

diktat-rules/src/test/kotlin/org/cqfn/diktat/ruleset/chapter3/FileStructureRuleTest.kt

@@ -25,6 +25,9 @@ class FileStructureRuleTest : LintTestBase(::FileStructureRule) {
         RulesConfig(FILE_WILDCARD_IMPORTS.name, true,
             mapOf("allowedWildcards" to "org.cqfn.diktat.example.*, org.cqfn.diktat.ruleset.constants.Warnings.*"))
     )
+    private val rulesConfigListEmptyDomainName: List<RulesConfig> = listOf(
+        RulesConfig("DIKTAT_COMMON", true, mapOf("domainName" to ""))
+    )
 
     @Test
     @Tag(WarningNames.FILE_CONTAINS_ONLY_COMMENTS)
@@ -226,4 +229,21 @@ class FileStructureRuleTest : LintTestBase(::FileStructureRule) {
             LintError(4, 1, ruleId, "${FILE_INCORRECT_BLOCKS_ORDER.warnText()} @file:Annotation", true)
         )
     }
+
+    @Test
+    @Tag(WarningNames.FILE_INCORRECT_BLOCKS_ORDER)
+    fun `test with empty domain name in config`() {
+        lintMethod(
+            """
+                |package org.cqfn.diktat.example
+                |
+                |import org.cqfn.diktat.example.Foo
+                |import com.pinterest.ktlint.core.LintError
+                |
+                |class Example
+            """.trimMargin(),
+            LintError(3, 1, ruleId, "${FILE_UNORDERED_IMPORTS.warnText()} import com.pinterest.ktlint.core.LintError...", true),
+            rulesConfigList = rulesConfigListEmptyDomainName
+        )
+    }
 }