From f970732c3bfb98dac72454b6a345459a84ad6786 Mon Sep 17 00:00:00 2001
From: Vineet Naik <vineet@helpshift.com>
Date: Sun, 12 Apr 2020 22:49:29 +0530
Subject: [PATCH] Extend the graphviz output format to support reverse flag

Earlier the graphviz output format didn't work if called with the
reverse flag. This is now fixed.

This commit also handles the case of more than one packages having
conflicting versions of the same dependency. In such cases, the edges
between dependency and the parent pkg will be labelled as per the
required version_spec of the respective dependency.
---
 pipdeptree.py | 41 ++++++++++++++++++++++++++++-------------
 1 file changed, 28 insertions(+), 13 deletions(-)

diff --git a/pipdeptree.py b/pipdeptree.py
index 17e7446..ba0ff97 100644
--- a/pipdeptree.py
+++ b/pipdeptree.py
@@ -575,7 +575,7 @@ def render_json_tree(tree, indent):
     return json.dumps([aux(p) for p in nodes], indent=indent)
 
 
-def dump_graphviz(tree, output_format='dot'):
+def dump_graphviz(tree, output_format='dot', is_reverse=False):
     """Output dependency graph as one of the supported GraphViz output formats.
 
     :param dict tree: dependency graph
@@ -599,17 +599,30 @@ def dump_graphviz(tree, output_format='dot'):
         sys.exit(1)
 
     graph = Digraph(format=output_format)
-    label = lambda p: '{0}\n{1}'.format(p.project_name, p.version)
-    missing_label = lambda d: '{0}\n(missing)'.format(d.project_name)
-    for pkg, deps in tree.items():
-        graph.node(pkg.key, label=label(pkg))
-        for dep in deps:
-            edge_label = dep.version_spec or 'any'
-            if dep.is_missing:
-                graph.node(dep.key, label=missing_label(dep), style='dashed')
-                graph.edge(pkg.key, dep.key, style='dashed')
-            else:
-                graph.edge(pkg.key, dep.key, label=edge_label)
+
+    if not is_reverse:
+        for pkg, deps in tree.items():
+            pkg_label = '{0}\n{1}'.format(pkg.project_name, pkg.version)
+            graph.node(pkg.key, label=pkg_label)
+            for dep in deps:
+                edge_label = dep.version_spec or 'any'
+                if dep.is_missing:
+                    dep_label = '{0}\n(missing)'.format(dep.project_name)
+                    graph.node(dep.key, label=dep_label, style='dashed')
+                    graph.edge(pkg.key, dep.key, style='dashed')
+                else:
+                    graph.edge(pkg.key, dep.key, label=edge_label)
+    else:
+        for dep, parents in tree.items():
+            dep_label = '{0}\n{1}'.format(dep.project_name,
+                                          dep.installed_version)
+            graph.node(dep.key, label=dep_label)
+            for parent in parents:
+                # req reference of the dep associated with this
+                # particular parent package
+                req_ref = parent.req
+                edge_label = req_ref.version_spec or 'any'
+                graph.edge(dep.key, parent.key, label=edge_label)
 
     # Allow output of dot format, even if GraphViz isn't installed.
     if output_format == 'dot':
@@ -802,7 +815,9 @@ def main():
     elif args.json_tree:
         print(render_json_tree(tree, indent=4))
     elif args.output_format:
-        output = dump_graphviz(tree, output_format=args.output_format)
+        output = dump_graphviz(tree,
+                               output_format=args.output_format,
+                               is_reverse=args.reverse)
         print_graphviz(output)
     else:
         render_text(tree, args.all, args.freeze)