Pyreverse: Use dashed lines for type-checking imports (#8824)

Author: nickdrozd

doc/whatsnew/fragments/8112.feature

@@ -0,0 +1,3 @@
+In Pyreverse package dependency diagrams, show when a module imports another only for type-checking.
+
+Closes #8112

pylint/pyreverse/diagrams.py

@@ -12,7 +12,7 @@
 import astroid
 from astroid import nodes, util
 
-from pylint.checkers.utils import decorated_with_property
+from pylint.checkers.utils import decorated_with_property, in_type_checking_block
 from pylint.pyreverse.utils import FilterMixIn
 
 
@@ -281,9 +281,15 @@ def get_module(self, name: str, node: nodes.Module) -> PackageEntity:
     def add_from_depend(self, node: nodes.ImportFrom, from_module: str) -> None:
         """Add dependencies created by from-imports."""
         mod_name = node.root().name
-        obj = self.module(mod_name)
-        if from_module not in obj.node.depends:
-            obj.node.depends.append(from_module)
+        package = self.module(mod_name).node
+
+        if from_module in package.depends:
+            return
+
+        if not in_type_checking_block(node):
+            package.depends.append(from_module)
+        elif from_module not in package.type_depends:
+            package.type_depends.append(from_module)
 
     def extract_relationships(self) -> None:
         """Extract relationships between nodes in the diagram."""
@@ -304,3 +310,10 @@ def extract_relationships(self) -> None:
                 except KeyError:
                     continue
                 self.add_relationship(package_obj, dep, "depends")
+
+            for dep_name in package_obj.node.type_depends:
+                try:
+                    dep = self.get_module(dep_name, package_obj.node)
+                except KeyError:  # pragma: no cover
+                    continue
+                self.add_relationship(package_obj, dep, "type_depends")

pylint/pyreverse/dot_printer.py

@@ -43,6 +43,11 @@ class HTMLLabels(Enum):
         "style": "solid",
     },
     EdgeType.USES: {"arrowtail": "none", "arrowhead": "open"},
+    EdgeType.TYPE_DEPENDENCY: {
+        "arrowtail": "none",
+        "arrowhead": "open",
+        "style": "dashed",
+    },
 }
 
 

pylint/pyreverse/inspector.py

@@ -139,6 +139,7 @@ def visit_module(self, node: nodes.Module) -> None:
             return
         node.locals_type = collections.defaultdict(list)
         node.depends = []
+        node.type_depends = []
         if self.tag:
             node.uid = self.generate_id()
 

pylint/pyreverse/mermaidjs_printer.py

@@ -24,6 +24,7 @@ class MermaidJSPrinter(Printer):
         EdgeType.ASSOCIATION: "--*",
         EdgeType.AGGREGATION: "--o",
         EdgeType.USES: "-->",
+        EdgeType.TYPE_DEPENDENCY: "-.->",
     }
 
     def _open_graph(self) -> None:

pylint/pyreverse/plantuml_printer.py

@@ -24,6 +24,7 @@ class PlantUmlPrinter(Printer):
         EdgeType.ASSOCIATION: "--*",
         EdgeType.AGGREGATION: "--o",
         EdgeType.USES: "-->",
+        EdgeType.TYPE_DEPENDENCY: "..>",
     }
 
     def _open_graph(self) -> None:

pylint/pyreverse/printer.py

@@ -25,6 +25,7 @@ class EdgeType(Enum):
     ASSOCIATION = "association"
     AGGREGATION = "aggregation"
     USES = "uses"
+    TYPE_DEPENDENCY = "type_dependency"
 
 
 class Layout(Enum):

pylint/pyreverse/writer.py

@@ -76,6 +76,13 @@ def write_packages(self, diagram: PackageDiagram) -> None:
                 type_=EdgeType.USES,
             )
 
+        for rel in diagram.get_relationships("type_depends"):
+            self.printer.emit_edge(
+                rel.from_object.fig_id,
+                rel.to_object.fig_id,
+                type_=EdgeType.TYPE_DEPENDENCY,
+            )
+
     def write_classes(self, diagram: ClassDiagram) -> None:
         """Write a class diagram."""
         # sorted to get predictable (hence testable) results

tests/pyreverse/data/classes_type_check_imports.dot

@@ -0,0 +1,4 @@
+digraph "classes_type_check_imports" {
+rankdir=BT
+charset="utf-8"
+}

tests/pyreverse/data/packages_type_check_imports.dot

@@ -0,0 +1,13 @@
+digraph "packages_type_check_imports" {
+rankdir=BT
+charset="utf-8"
+"package_diagrams" [color="black", label=<package_diagrams>, shape="box", style="solid"];
+"package_diagrams.type_check_imports" [color="black", label=<package_diagrams.type_check_imports>, shape="box", style="solid"];
+"package_diagrams.type_check_imports.mod_a" [color="black", label=<package_diagrams.type_check_imports.mod_a>, shape="box", style="solid"];
+"package_diagrams.type_check_imports.mod_b" [color="black", label=<package_diagrams.type_check_imports.mod_b>, shape="box", style="solid"];
+"package_diagrams.type_check_imports.mod_c" [color="black", label=<package_diagrams.type_check_imports.mod_c>, shape="box", style="solid"];
+"package_diagrams.type_check_imports.mod_d" [color="black", label=<package_diagrams.type_check_imports.mod_d>, shape="box", style="solid"];
+"package_diagrams.type_check_imports.mod_b" -> "package_diagrams.type_check_imports.mod_a" [arrowhead="open", arrowtail="none"];
+"package_diagrams.type_check_imports.mod_d" -> "package_diagrams.type_check_imports.mod_a" [arrowhead="open", arrowtail="none"];
+"package_diagrams.type_check_imports.mod_c" -> "package_diagrams.type_check_imports.mod_a" [arrowhead="open", arrowtail="none", style="dashed"];
+}