Show used solver in conda info output. (conda#13279)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

conda/base/context.py

@@ -1010,6 +1010,20 @@ def log_level(self) -> int:
         else:
             return logging.WARNING  # 30
 
+    def solver_user_agent(self):
+        user_agent = "solver/%s" % self.solver
+        try:
+            solver_backend = self.plugin_manager.get_cached_solver_backend()
+            # Solver.user_agent has to be a static or class method
+            user_agent += f" {solver_backend.user_agent()}"
+        except Exception as exc:
+            log.debug(
+                "User agent could not be fetched from solver class '%s'.",
+                self.solver,
+                exc_info=exc,
+            )
+        return user_agent
+
     @memoizedproperty
     def user_agent(self):
         builder = [f"conda/{CONDA_VERSION} requests/{self.requests_version}"]
@@ -1019,18 +1033,7 @@ def user_agent(self):
         if self.libc_family_version[0]:
             builder.append("%s/%s" % self.libc_family_version)
         if self.solver != "classic":
-            user_agent_str = "solver/%s" % self.solver
-            try:
-                solver_backend = self.plugin_manager.get_cached_solver_backend()
-                # Solver.user_agent has to be a static or class method
-                user_agent_str += f" {solver_backend.user_agent()}"
-            except Exception as exc:
-                log.debug(
-                    "User agent could not be fetched from solver class '%s'.",
-                    self.solver,
-                    exc_info=exc,
-                )
-            builder.append(user_agent_str)
+            builder.append(self.solver_user_agent())
         return " ".join(builder)
 
     @contextmanager

conda/cli/main_info.py

@@ -209,7 +209,13 @@ def print_package_info(packages):
 def get_info_dict(system=False):
     from .. import CONDA_PACKAGE_ROOT
     from .. import __version__ as conda_version
-    from ..base.context import context, env_name, sys_rc_path, user_rc_path
+    from ..base.context import (
+        DEFAULT_SOLVER,
+        context,
+        env_name,
+        sys_rc_path,
+        user_rc_path,
+    )
     from ..common.compat import on_win
     from ..common.url import mask_anaconda_token
     from ..core.index import _supplement_index_with_system
@@ -242,6 +248,12 @@ def get_info_dict(system=False):
 
     active_prefix_name = env_name(context.active_prefix)
 
+    solver = {
+        "name": context.solver,
+        "user_agent": context.solver_user_agent(),
+        "default": context.solver == DEFAULT_SOLVER,
+    }
+
     info_dict = dict(
         platform=context.subdir,
         conda_version=conda_version,
@@ -272,6 +284,7 @@ def get_info_dict(system=False):
         config_files=context.config_files,
         netrc_file=netrc_file,
         virtual_pkgs=virtual_pkgs,
+        solver=solver,
     )
     if on_win:
         from ..common._os.windows import is_admin_on_windows
@@ -350,6 +363,10 @@ def builder():
         yield ("conda version", info_dict["conda_version"])
         yield ("conda-build version", info_dict["conda_build_version"])
         yield ("python version", info_dict["python_version"])
+        yield (
+            "solver",
+            f"{info_dict['solver']['name']}{' (default)' if info_dict['solver']['default'] else ''}",
+        )
         yield (
             "virtual packages",
             flatten("=".join(pkg) for pkg in info_dict["virtual_pkgs"]),

news/13265-show-solver-conda-info

@@ -0,0 +1,19 @@
+### Enhancements
+
+* Show the used solver in `conda info` output to simplify debugging. (#13265)
+
+### Bug fixes
+
+* <news item>
+
+### Deprecations
+
+* <news item>
+
+### Docs
+
+* <news item>
+
+### Other
+
+* <news item>

tests/cli/test_main_info.py

@@ -50,6 +50,7 @@ def test_info(conda_cli: CondaCLIFixture):
     assert "channel URLs" in stdout_basic
     assert "config file" in stdout_basic
     assert "offline mode" in stdout_basic
+    assert "solver" in stdout_basic
     assert not stderr
     assert not err
 
@@ -95,6 +96,7 @@ def test_info_json(conda_cli: CondaCLIFixture):
         "rc_path",
         "root_prefix",
         "root_writable",
+        "solver",
     } <= set(parsed)