Some backports

libmamba/include/mamba/core/channel.hpp

@@ -100,6 +100,7 @@ namespace mamba
 
         const Channel& get_channel_alias() const;
         const channel_map& get_custom_channels() const;
+        const multichannel_map& get_custom_multichannels() const;
 
     private:
 
@@ -111,8 +112,6 @@ namespace mamba
         Channel build_channel_alias();
         void init_custom_channels();
 
-        const multichannel_map& get_custom_multichannels() const;
-
         Channel make_simple_channel(
             const Channel& channel_alias,
             const std::string& channel_url,

libmamba/src/core/pool.cpp

@@ -171,6 +171,15 @@ namespace mamba
             }
             std::string needle_subdir = util::rsplit(needle_channel, "/", 1)[1];
 
+            auto known_platforms = get_known_platforms();
+            if (std::find(known_platforms.begin(), known_platforms.end(), needle_subdir)
+                == known_platforms.end())
+            {
+                // Not a known subdir. This can happen for specs like pkgs/main.
+                // so any subdir is fine
+                return true;
+            }
+
             std::string candidate_repo_subdir = util::rsplit(candidate_repo_url, "/", 1)[1];
 
             if (candidate_repo_subdir == needle_subdir)
@@ -207,7 +216,20 @@ namespace mamba
                 ms.conda_build_form().c_str()
             );
 
-            const Channel& c = channel_context.make_channel(ms.channel);
+            auto multi_channels = channel_context.get_custom_multichannels();
+            std::vector<const Channel*> channels;
+            auto multi_channels_it = multi_channels.find(ms.channel);
+            if (multi_channels_it != multi_channels.end())
+            {
+                for (auto& c : multi_channels_it->second)
+                {
+                    channels.push_back(&channel_context.make_channel(c));
+                }
+            }
+            else
+            {
+                channels.push_back(&channel_context.make_channel(ms.channel));
+            }
             solv::ObjQueue selected_pkgs = {};
             pool.for_each_whatprovides(
                 match,
@@ -218,11 +240,14 @@ namespace mamba
                     auto repo = solv::ObjRepoView(*s.raw()->repo);
                     // TODO make_channel should disapear avoiding conflict here
                     auto const url = std::string(repo.url());
-                    if (channel_match(channel_context, channel_context.make_channel(url), c))
+                    for (auto& c : channels)
                     {
-                        if (subdir_match(url, ms.spec))
+                        if (channel_match(channel_context, channel_context.make_channel(url), *c))
                         {
-                            selected_pkgs.push_back(s.id());
+                            if (subdir_match(url, ms.spec))
+                            {
+                                selected_pkgs.push_back(s.id());
+                            }
                         }
                     }
                 }

libmamba/src/core/virtual_packages.cpp

@@ -162,6 +162,34 @@ namespace mamba
             return res;
         }
 
+        std::string get_archspec_x86_64()
+        {
+#if (defined(__GNUC__) || defined(__clang__)) && __x86_64__
+            /* if (__builtin_cpu_supports ("x86-64-v4")) */
+            if (__builtin_cpu_supports("avx512f") && __builtin_cpu_supports("avx512bw")
+                && __builtin_cpu_supports("avx512cd") && __builtin_cpu_supports("avx512dq")
+                && __builtin_cpu_supports("avx512vl"))
+            {
+                return "x86_64-v4";
+            }
+            /* if (__builtin_cpu_supports ("x86-64-v3")) */
+            if (__builtin_cpu_supports("avx") && __builtin_cpu_supports("avx2")
+                && __builtin_cpu_supports("bmi") && __builtin_cpu_supports("bmi2")
+                && __builtin_cpu_supports("fma"))
+            {
+                return "x86_64-v3";
+            }
+            /* if (__builtin_cpu_supports ("x86-64-v2")) */
+            if (__builtin_cpu_supports("popcnt") && __builtin_cpu_supports("sse3")
+                && __builtin_cpu_supports("ssse3") && __builtin_cpu_supports("sse4.1")
+                && __builtin_cpu_supports("sse4.2"))
+            {
+                return "x86_64-v2";
+            }
+#endif
+            return "x86_64";
+        }
+
         std::vector<PackageInfo> dist_packages()
         {
             LOG_DEBUG << "Loading distribution virtual packages";
@@ -221,7 +249,7 @@ namespace mamba
 
             if (arch == "64")
             {
-                arch = "x86_64";
+                arch = get_archspec_x86_64();
             }
             else if (arch == "32")
             {

libmamba/tests/src/core/test_virtual_packages.cpp

@@ -70,7 +70,7 @@ namespace mamba
                 }
 #if __x86_64__ || defined(_WIN64)
                 CHECK_EQ(pkgs.back().name, "__archspec");
-                CHECK_EQ(pkgs.back().build_string, "x86_64");
+                CHECK_EQ(pkgs.back().build_string.find("x86_64"), 0);
 #endif
 
                 // This is bad design, tests should not interfer

micromamba/tests/test_create.py

@@ -624,6 +624,26 @@ def test_spec_with_channel_and_subdir():
         )
 
 
+def test_spec_with_multichannel(tmp_home, tmp_root_prefix):
+    "https://github.com/mamba-org/mamba/pull/2927"
+    helpers.create("-n", "myenv", "defaults::zlib", "--dry-run")
+
+
+def test_spec_with_slash_in_channel(tmp_home, tmp_root_prefix):
+    "https://github.com/mamba-org/mamba/pull/2926"
+    with pytest.raises(subprocess.CalledProcessError) as info:
+        helpers.create("-n", "env1", "pkgs/main/noarch::python", "--dry-run")
+
+    assert info.value.stderr.decode() == (
+        'critical libmamba The package "pkgs/main/noarch::python" is '
+        "not available for the specified platform\n"
+    )
+
+    os.environ["CONDA_SUBDIR"] = "linux-64"
+    helpers.create("-n", "env2", "pkgs/main/linux-64::python", "--dry-run")
+    helpers.create("-n", "env3", "pkgs/main::python", "--dry-run")
+
+
 @pytest.mark.parametrize("shared_pkgs_dirs", [True], indirect=True)
 def test_channel_nodefaults(tmp_home, tmp_root_prefix, tmp_path):
     rc_file = tmp_path / "rc.yaml"