Improve dependency resolution debug info

poetry/console/commands/command.py

@@ -7,7 +7,12 @@ from ..styles.poetry import PoetryStyle
 
 class CommandFormatter(logging.Formatter):
 
-    _colors = {"error": "fg=red", "warning": "fg=yellow", "debug": "fg=blue"}
+    _colors = {
+        "error": "fg=red",
+        "warning": "fg=yellow",
+        "debug": "debug",
+        "info": "fg=blue",
+    }
 
     def format(self, record):
         if not record.exc_info:

poetry/console/styles/poetry.py

@@ -10,6 +10,7 @@ class PoetryStyle(CleoStyle):
         self.output.get_formatter().add_style("warning", "yellow")
         self.output.get_formatter().add_style("question", "blue")
         self.output.get_formatter().add_style("comment", "cyan")
+        self.output.get_formatter().add_style("debug", "black", options=["bold"])
 
     def writeln(
         self,

poetry/mixology/version_solver.py

@@ -169,7 +169,7 @@ class VersionSolver:
             return _conflict
 
         self._log(
-            "<fg=blue>derived</>: {}{}".format(
+            "derived: {}{}".format(
                 "not " if unsatisfied.is_positive() else "", unsatisfied.dependency
             )
         )
@@ -193,7 +193,7 @@ class VersionSolver:
 
         .. _conflict resolution: https://github.com/dart-lang/pub/tree/master/doc/solver.md#conflict-resolution
         """
-        self._log("<fg=red;options=bold>conflict</>: {}".format(incompatibility))
+        self._log("conflict: {}".format(incompatibility))
 
         new_incompatibility = False
         while not incompatibility.is_failure():
@@ -302,7 +302,7 @@ class VersionSolver:
             new_incompatibility = True
 
             partially = "" if difference is None else " partially"
-            bang = "<fg=red>!</>"
+            bang = "!"
             self._log(
                 "{} {} is{} satisfied by {}".format(
                     bang, most_recent_term, partially, most_recent_satisfier
@@ -397,9 +397,7 @@ class VersionSolver:
         if not conflict:
             self._solution.decide(version)
             self._log(
-                "<fg=blue>selecting</> {} ({})".format(
-                    version.name, version.full_pretty_version
-                )
+                "selecting {} ({})".format(version.name, version.full_pretty_version)
             )
 
         return dependency.name
@@ -420,7 +418,7 @@ class VersionSolver:
         )
 
     def _add_incompatibility(self, incompatibility):  # type: (Incompatibility) -> None
-        self._log("<fg=blue>fact</>: {}".format(incompatibility))
+        self._log("fact: {}".format(incompatibility))
 
         for term in incompatibility.terms:
             if term.dependency.name not in self._incompatibilities:

poetry/puzzle/provider.py

 import logging
 import os
 import pkginfo
+import re
 import shutil
 import time
 
@@ -360,7 +361,9 @@ class Provider:
                     dependencies.append(deps[0])
                     continue
 
-                self.debug("Duplicate dependencies for {}".format(dep_name))
+                self.debug(
+                    "<debug>Duplicate dependencies for {}</debug>".format(dep_name)
+                )
 
                 # Regrouping by constraint
                 by_constraint = {}
@@ -465,6 +468,42 @@ class Provider:
         return self._io
 
     def debug(self, message, depth=0):
+        if message.startswith("fact:"):
+            if "depends on" in message:
+                message = re.sub(
+                    "fact: (.+?)(?:( \()(.+?)(\)))? depends on (.+?) \((.+?)\)",
+                    "<fg=blue>fact</>: <info>\\1</info>\\2<comment>\\3</comment>\\4 "
+                    "depends on <info>\\5</info> (<comment>\\6</comment>)",
+                    message,
+                )
+            else:
+                message = re.sub(
+                    "fact: (.+) is (.+)",
+                    "<fg=blue>fact</>: <info>\\1</info> is <comment>\\2</comment>",
+                    message,
+                )
+        elif message.startswith("selecting "):
+            message = re.sub(
+                "selecting (.+?) \((.+?)\)",
+                "<fg=blue>selecting</> <info>\\1</info> (<comment>\\2</comment>)",
+                message,
+            )
+        elif message.startswith("derived:"):
+            message = re.sub(
+                "derived: (.+?)(?:( \()(.+?)(\)))?$",
+                "<fg=blue>derived</>: <info>\\1</info>\\2<comment>\\3</comment>\\4",
+                message,
+            )
+        elif message.startswith("conflict:"):
+            message = re.sub(
+                "conflict: (.+?)(?:( \()(.+?)(\)))? depends on (.+?) \((.+?)\)",
+                "<fg=red;options=bold>conflict</>: <info>\\1</info>\\2<comment>\\3</comment>\\4 "
+                "depends on <info>\\5</info> (<comment>\\6</comment>)",
+                message,
+            )
+
+        message = message.replace("! ", "<error>!</error> ")
+
         if self.is_debugging():
             debug_info = str(message)
             debug_info = (