Import Control checker (port from Checkstyle)

import-control.xml

@@ -0,0 +1,13 @@
+<import-control pkg="org.scalastyle" regex="false">
+    <allow pkg="org.scalastyle" exact-match="false" local-only="false" regex="false" />
+    <allow pkg="java" exact-match="false" local-only="false" />
+    <allow pkg="scala" exact-match="false" local-only="false" />
+    <allow pkg="(?:_root_\.)?scalariform" exact-match="false" local-only="false" />
+    <allow pkg="com.typesafe.config" exact-match="false" regex="false" />
+    <subpackage name="file">
+        <disallow pkg="(?:_root_\.)?org.scalariform" exact-match="false" />
+    </subpackage>
+    <subpackage name="util">
+        <allow pkg="com.typesafe.config" exact-match="false" regex="false" />
+    </subpackage>
+</import-control>

src/main/resources/default_config.xml

@@ -309,4 +309,9 @@
   </check>
   <check class="org.scalastyle.scalariform.CurliesImportChecker" level="warning" enabled="false" />
   <check class="org.scalastyle.scalariform.ThrowChecker" level="warning" enabled="true" />
+  <check level="warning" class="org.scalastyle.scalariform.ImportControlChecker" enabled="true">
+    <parameters>
+      <parameter name="file"><![CDATA[import-control.xml]]></parameter>
+    </parameters>
+  </check>
 </scalastyle>

src/main/resources/import_control_1_4.dtd

@@ -0,0 +1,107 @@
+<!-- Add the following to any file that is to be validated against this DTD:
+
+<!DOCTYPE import-control PUBLIC
+    "-//Checkstyle//DTD ImportControl Configuration 1.4//EN"
+    "https://checkstyle.org/dtds/import_control_1_4.dtd">
+-->
+
+<!--
+  The root element of the configuration file.
+-->
+<!ELEMENT import-control ((allow|disallow)*,(subpackage|file)*)>
+
+<!--
+  pkg - The root package to be checked. For example "com.puppycrawl".
+
+  regex - Root package name has to be interpreted as
+  regular expression.
+
+  strategyOnMismatch - Strategy in a case if matching allow/disallow rule
+  was not found. Possible values: allowed, disallowed.
+  If not defined explicitly, has "disallowed" value by default.
+-->
+<!ATTLIST import-control
+  pkg CDATA #REQUIRED
+  strategyOnMismatch (allowed|disallowed) #IMPLIED
+  regex (true) #IMPLIED>
+
+<!--
+  Represents a subpackage of the parent element.
+-->
+<!ELEMENT subpackage ((allow|disallow)*,(subpackage|file)*)>
+
+<!--
+  name - The name of the subpackage. For example if the name is "tools"
+  and the parent is "com.puppycrawl", then it corresponds to the
+  package "com.puppycrawl.tools". If the regex attribute is "true" the
+  name is interpreted as a regular expression.
+
+  regex - Subpackage name has to be interpreted as
+  regular expression.
+
+  strategyOnMismatch - Strategy in a case if matching allow/disallow rule
+  was not found. Possible values: allowed, disallowed, delegateToParent.
+  If not defined explicitly, has "delegateToParent" value by default.
+-->
+<!ATTLIST subpackage
+  name CDATA #REQUIRED
+  strategyOnMismatch (delegateToParent|allowed|disallowed) #IMPLIED
+  regex (true) #IMPLIED>
+
+<!--
+  Represents a file of the parent element.
+-->
+<!ELEMENT file (allow|disallow)*>
+
+<!--
+  name - The name of the file.
+  If the regex attribute is "true" the name is interpreted as a regular expression.
+
+  regex - File name has to be interpreted as regular expression.
+-->
+<!ATTLIST file
+  name CDATA #REQUIRED
+  regex (true) #IMPLIED>
+
+<!--
+  Represents attributes for an import rule which can either allow or
+  disallow access.
+
+  pkg - The fully qualified name of the package to allow/disallow.
+  Cannot be specified in conjunction with "class".
+
+  class - The fully qualified name of the class to allow/disallow.
+  Cannot be specified in conjunction with "pkg".
+
+  exact-match - Only valid with "pkg". Specifies whether the package
+  name matching should be exact. For example, the pkg
+  "com.puppycrawl.tools" will match the import
+  "com.puppycrawl.tools.checkstyle.api.*" when the option is not set,
+  but will not match if the option is set.
+
+  local-only - Indicates that the rule is to apply only to the current
+  package and not to subpackages.
+
+  regex - Indicates that the class or package name has to be interpreted as
+  regular expression.
+-->
+<!ENTITY % attlist.importrule "
+  pkg CDATA #IMPLIED
+  exact-match (true) #IMPLIED
+  class CDATA #IMPLIED
+  local-only (true) #IMPLIED
+  regex (true) #IMPLIED">
+
+<!--
+  Represents an import rule that will allow access.
+-->
+<!ELEMENT allow EMPTY>
+<!ATTLIST allow
+  %attlist.importrule;>
+
+<!--
+  Represents an import rule that will disallow access.
+-->
+<!ELEMENT disallow EMPTY>
+<!ATTLIST disallow
+  %attlist.importrule;>

src/main/resources/reference.conf

@@ -411,3 +411,9 @@ disallow.case.brace.description = "Checks that braces aren't used in case clause
 throw.message = "Avoid using throw statements."
 throw.label = "No throw statements."
 throw.description = "Checks that throw is not used."
+
+import.control.message = "Import not allowed: ''{0}'' by ''{1}'' in package {2}"
+import.control.label = "Control imports per file or package"
+import.control.description = "Control imports per file or package"
+import.control.file.label = "File configuring imports per file or package"
+import.control.file.description = "File configuring imports per file or package"

src/main/resources/scalastyle_definition.xml

@@ -218,4 +218,9 @@
   </checker>
   <checker class="org.scalastyle.scalariform.WhileBraceChecker" id="while.brace" defaultLevel="warning"/>
   <checker class="org.scalastyle.scalariform.CaseBraceChecker" id="disallow.case.brace" defaultLevel="warning"/>
+  <checker class="org.scalastyle.scalariform.ImportControlChecker" id="import.control" defaultLevel="warning">
+    <parameters>
+      <parameter name="file" type="string" />
+    </parameters>
+  </checker>
 </scalastyle-definition>

src/main/resources/scalastyle_documentation.xml

@@ -905,4 +905,19 @@ To fix it, replace the (unicode operator) `⇒` with `=>`.
       ]]>
     </example-configuration>
   </check>
+  <check id="import.control">
+    <justification>
+      Allow fine-grained control over imports in files and packages.
+    </justification>
+    <extra-description>The import control specification is the exact same as Checkstyle's Import Control checker. See https://checkstyle.sourceforge.io/config_imports.html#ImportControl for more information.</extra-description>
+    <example-configuration>
+      <![CDATA[
+    <check level="warning" class="org.scalastyle.scalariform.ImportControlChecker" enabled="true">
+      <parameters>
+        <parameter name="file">import-control.xml</parameter>
+      </parameters>
+    </check>
+ ]]>
+    </example-configuration>
+  </check>
 </scalastyle-documentation>