feat: add reverse flag to list command

libmamba/src/api/list.cpp

@@ -24,6 +24,7 @@ namespace mamba
         {
             bool full_name;
             bool no_pip;
+            bool reverse;
         };
 
         struct formatted_pkg
@@ -36,6 +37,11 @@ namespace mamba
             return a.name < b.name;
         }
 
+        bool compare_reverse_alphabetically(const formatted_pkg& a, const formatted_pkg& b)
+        {
+            return a.name >= b.name;
+        }
+
         std::string strip_from_filename_and_platform(
             const std::string& full_str,
             const std::string& filename,
@@ -75,6 +81,7 @@ namespace mamba
                 regex = '^' + regex + '$';
             }
 
+
             std::regex spec_pat(regex);
             auto all_records = prefix_data.all_pkg_mgr_records();
 
@@ -87,7 +94,18 @@ namespace mamba
                 {
                     keys.push_back(pkg.first);
                 }
-                std::sort(keys.begin(), keys.end());
+                if (options.reverse)
+                {
+                    std::sort(
+                        keys.begin(),
+                        keys.end(),
+                        [](const std::string& a, const std::string& b) { return a > b; }
+                    );
+                }
+                else
+                {
+                    std::sort(keys.begin(), keys.end());
+                }
 
                 for (const auto& key : keys)
                 {
@@ -168,7 +186,9 @@ namespace mamba
                 }
             }
 
-            std::sort(packages.begin(), packages.end(), compare_alphabetically);
+            auto comparable = options.reverse ? compare_reverse_alphabetically
+                                              : compare_alphabetically;
+            std::sort(packages.begin(), packages.end(), comparable);
 
             // format and print table
             printers::Table t({ "Name", "Version", "Build", "Channel" });
@@ -208,6 +228,7 @@ namespace mamba
         detail::list_options options;
         options.full_name = config.at("full_name").value<bool>();
         options.no_pip = config.at("no_pip").value<bool>();
+        options.reverse = config.at("reverse").value<bool>();
 
         auto channel_context = ChannelContext::make_conda_compatible(config.context());
         detail::list_packages(config.context(), regex, channel_context, std::move(options));

micromamba/src/list.cpp

@@ -33,6 +33,10 @@ init_list_parser(CLI::App* subcom, Configuration& config)
                                      .description("Do not include pip-only installed packages."));
     subcom->add_flag("--no-pip", no_pip.get_cli_config<bool>(), no_pip.description());
 
+    auto& reverse = config.insert(
+        Configurable("reverse", false).group("cli").description("List installed packages in reverse order.")
+    );
+    subcom->add_flag("--reverse", reverse.get_cli_config<bool>(), reverse.description());
     // TODO: implement this in libmamba/list.cpp
     /*auto& canonical = config.insert(Configurable("canonical", false)
                                         .group("cli")

micromamba/tests/test_list.py

@@ -7,16 +7,19 @@
 from . import helpers
 
 
+@pytest.mark.parametrize("reverse_flag", ["", "--reverse"])
 @pytest.mark.parametrize("quiet_flag", ["", "-q", "--quiet"])
 @pytest.mark.parametrize("env_selector", ["", "name", "prefix"])
 @pytest.mark.parametrize("shared_pkgs_dirs", [True], indirect=True)
-def test_list(tmp_home, tmp_root_prefix, tmp_env_name, tmp_xtensor_env, env_selector, quiet_flag):
+def test_list(
+    tmp_home, tmp_root_prefix, tmp_env_name, tmp_xtensor_env, env_selector, quiet_flag, reverse_flag
+):
     if env_selector == "prefix":
-        res = helpers.umamba_list("-p", tmp_xtensor_env, "--json", quiet_flag)
+        res = helpers.umamba_list("-p", tmp_xtensor_env, "--json", quiet_flag, reverse_flag)
     elif env_selector == "name":
-        res = helpers.umamba_list("-n", tmp_env_name, "--json", quiet_flag)
+        res = helpers.umamba_list("-n", tmp_env_name, "--json", quiet_flag, reverse_flag)
     else:
-        res = helpers.umamba_list("--json", quiet_flag)
+        res = helpers.umamba_list("--json", quiet_flag, reverse_flag)
 
     assert len(res) > 2
 
@@ -28,6 +31,50 @@ def test_list(tmp_home, tmp_root_prefix, tmp_env_name, tmp_xtensor_env, env_sele
         for i in res
     )
 
+    if reverse_flag == "--reverse":
+        assert names.index("xtensor") > names.index("xtl")
+    else:
+        assert names.index("xtensor") < names.index("xtl")
+
+
+@pytest.mark.parametrize("reverse_flag", ["", "--reverse"])
+@pytest.mark.parametrize("quiet_flag", ["", "-q", "--quiet"])
+@pytest.mark.parametrize("env_selector", ["", "name", "prefix"])
+@pytest.mark.parametrize("shared_pkgs_dirs", [True], indirect=True)
+def test_list_no_json(
+    tmp_home, tmp_root_prefix, tmp_env_name, tmp_xtensor_env, env_selector, quiet_flag, reverse_flag
+):
+    if env_selector == "prefix":
+        res = helpers.umamba_list("-p", tmp_xtensor_env, quiet_flag, reverse_flag)
+    elif env_selector == "name":
+        res = helpers.umamba_list("-n", tmp_env_name, quiet_flag, reverse_flag)
+    else:
+        res = helpers.umamba_list(quiet_flag, reverse_flag)
+
+    assert len(res) > 10
+
+    assert "xtensor" in res
+    assert "xtl" in res
+
+    # This is what res looks like in this case:
+    # List of packages in environment: "/tmp/xxx"
+
+    # Name           Version  Build        Channel
+    # ────────────────────────────────────────────────────
+    # _libgcc_mutex  0.1      conda_forge  conda-forge
+    # _openmp_mutex  4.5      2_gnu        conda-forge
+    header_delimiter = "\u2500"
+    packages = res[res.rindex(header_delimiter) :].split("\n", 1)[1]
+    packages_list = packages.strip().split("\n")
+
+    for package in packages_list:
+        assert package[-11:] == "conda-forge"
+
+    if reverse_flag == "--reverse":
+        assert res.find("xtensor") > res.find("xtl")
+    else:
+        assert res.find("xtensor") < res.find("xtl")
+
 
 @pytest.mark.parametrize("quiet_flag", ["", "-q", "--quiet"])
 @pytest.mark.parametrize("shared_pkgs_dirs", [True], indirect=True)