Make PackageInfo comparable

Signed-off-by: Julien Jerphanion <[email protected]>

Author: jjerphan

libmamba/include/mamba/specs/package_info.hpp

@@ -85,6 +85,8 @@ namespace mamba::specs
 
     auto operator!=(const PackageInfo& lhs, const PackageInfo& rhs) -> bool;
 
+    auto operator<(const PackageInfo& lhs, const PackageInfo& rhs) -> bool;
+
     void to_json(nlohmann::json& j, const PackageInfo& pkg);
 
     void from_json(const nlohmann::json& j, PackageInfo& pkg);

libmamba/src/core/context.cpp

@@ -19,6 +19,7 @@
 #include "mamba/core/thread_utils.hpp"
 #include "mamba/core/util.hpp"
 #include "mamba/core/util_os.hpp"
+#include "mamba/specs/package_info.hpp"
 #include "mamba/util/encoding.hpp"
 #include "mamba/util/environment.hpp"
 #include "mamba/util/path_manip.hpp"

libmamba/src/specs/package_info.cpp

@@ -466,6 +466,51 @@ namespace mamba::specs
         return !(lhs == rhs);
     }
 
+    auto operator<(const PackageInfo& lhs, const PackageInfo& rhs) -> bool
+    {
+        // Compare name first
+        if (lhs.name != rhs.name)
+        {
+            return lhs.name < rhs.name;
+        }
+
+        // If track features are present, prefer the package having the least of them
+        if (lhs.track_features.size() != rhs.track_features.size())
+        {
+            return lhs.track_features.size() > rhs.track_features.size();
+        }
+
+        // Then version
+        if (lhs.version != rhs.version)
+        {
+            return lhs.version < rhs.version;
+        }
+
+        // Then build string
+        if (lhs.build_string != rhs.build_string)
+        {
+            return lhs.build_string < rhs.build_string;
+        }
+
+        // Then build number
+        if (lhs.build_number != rhs.build_number)
+        {
+            return lhs.build_number < rhs.build_number;
+        }
+
+        // We could add the `dependencies` comparison here, but it's costly
+        // and not needed.
+
+        // Then channel
+        if (lhs.channel != rhs.channel)
+        {
+            return lhs.channel < rhs.channel;
+        }
+
+        // If all else is equal, compare package URL
+        return lhs.package_url < rhs.package_url;
+    }
+
     void to_json(nlohmann::json& j, const PackageInfo& pkg)
     {
         j["name"] = pkg.name;