[MLA-1587] Don't warn about minor version mismatch, add links in specific messages (#4688)

* Don't warn about minor version mismatch, add links in specific messages

* changelog

* fix tests

com.unity.ml-agents/CHANGELOG.md

 
 ### Bug Fixes
 #### com.unity.ml-agents (C#)
+- Removed noisy warnings about API minor version mismatches in both the C# and python code. (#4688)
 #### ml-agents / ml-agents-envs / gym-unity (Python)
 
 

com.unity.ml-agents/Runtime/Communicator/GrpcExtensions.cs

                 {
                     if (!s_HaveWarnedTrainerCapabilitiesMultiPng)
                     {
-                        Debug.LogWarning($"Attached trainer doesn't support multiple PNGs. Switching to uncompressed observations for sensor {sensor.GetName()}.");
+                        Debug.LogWarning(
+                            $"Attached trainer doesn't support multiple PNGs. Switching to uncompressed observations for sensor {sensor.GetName()}. " +
+                            "Please find the versions that work best together from our release page: " +
+                            "https://github.com/Unity-Technologies/ml-agents/releases"
+                        );
                         s_HaveWarnedTrainerCapabilitiesMultiPng = true;
                     }
                     compressionType = SensorCompressionType.None;
                 {
                     if (!s_HaveWarnedTrainerCapabilitiesMapping)
                     {
-                        Debug.LogWarning($"The sensor {sensor.GetName()} is using non-trivial mapping and " +
+                        Debug.LogWarning(
+                            $"The sensor {sensor.GetName()} is using non-trivial mapping and " +
-                            "Switching to uncompressed observations.");
+                            "Switching to uncompressed observations. " +
+                            "Please find the versions that work best together from our release page: " +
+                            "https://github.com/Unity-Technologies/ml-agents/releases"
+                        );
                         s_HaveWarnedTrainerCapabilitiesMapping = true;
                     }
                     compressionType = SensorCompressionType.None;

com.unity.ml-agents/Runtime/Communicator/RpcCommunicator.cs

             }
             else if (unityVersion.Minor != pythonVersion.Minor)
             {
-                // Even if we initialize, we still want to check to make sure that we inform users of minor version
-                // changes.  This will surface any features that may not work due to minor version incompatibilities.
-                Debug.LogWarningFormat(
-                    "WARNING: The communication API versions between Unity and python differ at the minor version level. " +
-                    "Python API: {0}, Unity API: {1} Python Library Version: {2} .\n" +
-                    "This means that some features may not work unless you upgrade the package with the lower version." +
-                    "Please find the versions that work best together from our release page.\n" +
-                    "https://github.com/Unity-Technologies/ml-agents/releases",
-                    pythonApiVersion, unityCommunicationVersion, pythonLibraryVersion
-                );
+                // If a feature is used in Unity but not supported in the trainer,
+                // we will warn at the point it's used. Don't warn here to avoid noise.
             }
             return true;
         }

com.unity.ml-agents/Tests/Editor/Communicator/RpcCommunicatorTests.cs

             Assert.IsTrue(RpcCommunicator.CheckCommunicationVersionsAreCompatible(unityVerStr,
                 pythonVerStr,
                 pythonPackageVerStr));
-
-            // Ensure that a warning was printed.
-            LogAssert.Expect(LogType.Warning, new Regex("(.\\s)+"));
+            LogAssert.NoUnexpectedReceived();
 
             unityVerStr = "2.0.0";
             Assert.IsFalse(RpcCommunicator.CheckCommunicationVersionsAreCompatible(unityVerStr,

ml-agents-envs/mlagents_envs/environment.py

         elif unity_communicator_version.version[0] != api_version.version[0]:
             # Major versions mismatch.
             return False
-        elif unity_communicator_version.version[1] != api_version.version[1]:
-            # Non-beta minor versions mismatch.  Log a warning but allow execution to continue.
-            logger.warning(
-                f"WARNING: The communication API versions between Unity and python differ at the minor version level. "
-                f"Python API: {python_api_version}, Unity API: {unity_communicator_version}.\n"
-                f"This means that some features may not work unless you upgrade the package with the lower version."
-                f"Please find the versions that work best together from our release page.\n"
-                "https://github.com/Unity-Technologies/ml-agents/releases"
-            )
+            # Major versions match, so either:
+            # 1) The versions are identical, in which case there's no compatibility issues
+            # 2) The Unity version is newer, in which case we'll warn or fail on the Unity side if trying to use
+            #    unsupported features
+            # 3) The trainer version is newer, in which case new trainer features might be available but unused by C#
+            # In any of the cases, there's no reason to warn about mismatch here.
             logger.info(
                 f"Connected to Unity environment with package version {unity_package_version} "
                 f"and communication version {unity_com_ver}"