[MNG-5754] Toolchains should be read during initialization

MavenExecutionRequest has been extended with toolchains, which is filled by MavenCli
Interfaces have been extended with new methods, assuming only Maven provides implementations

maven-core/src/main/java/org/apache/maven/execution/DefaultMavenExecutionRequest.java

@@ -22,7 +22,9 @@ package org.apache.maven.execution;
 import java.io.File;
 import java.util.ArrayList;
 import java.util.Date;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.Properties;
 
 import org.apache.maven.artifact.repository.ArtifactRepository;
@@ -32,6 +34,7 @@ import org.apache.maven.project.ProjectBuildingRequest;
 import org.apache.maven.settings.Mirror;
 import org.apache.maven.settings.Proxy;
 import org.apache.maven.settings.Server;
+import org.apache.maven.toolchain.model.ToolchainModel;
 import org.eclipse.aether.DefaultRepositoryCache;
 import org.eclipse.aether.RepositoryCache;
 import org.eclipse.aether.repository.WorkspaceReader;
@@ -140,6 +143,8 @@ public class DefaultMavenExecutionRequest
 
     private String builderId = "singlethreaded";
     
+    private Map<String, List<ToolchainModel>> toolchains;
+
     /**
      * Suppress SNAPSHOT updates.
      *
@@ -1127,4 +1132,21 @@ public class DefaultMavenExecutionRequest
     {
         return builderId;
     }
+    
+    @Override
+    public Map<String, List<ToolchainModel>> getToolchains()
+    {
+        if ( toolchains == null )
+        {
+            toolchains = new HashMap<String, List<ToolchainModel>>();
+        }
+        return toolchains;
+    }
+
+    @Override
+    public MavenExecutionRequest setToolchains( Map<String, List<ToolchainModel>> toolchains )
+    {
+        this.toolchains = toolchains;
+        return this;
+    }
 }

maven-core/src/main/java/org/apache/maven/execution/DefaultMavenExecutionRequestPopulator.java

@@ -20,8 +20,11 @@ package org.apache.maven.execution;
  */
 
 import java.io.File;
+import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Map;
 import java.util.Set;
 
 import org.apache.maven.artifact.InvalidRepositoryException;
@@ -34,6 +37,8 @@ import org.apache.maven.settings.Repository;
 import org.apache.maven.settings.Server;
 import org.apache.maven.settings.Settings;
 import org.apache.maven.settings.SettingsUtils;
+import org.apache.maven.toolchain.model.PersistedToolchains;
+import org.apache.maven.toolchain.model.ToolchainModel;
 import org.codehaus.plexus.component.annotations.Component;
 import org.codehaus.plexus.component.annotations.Requirement;
 import org.codehaus.plexus.util.StringUtils;
@@ -46,6 +51,7 @@ public class DefaultMavenExecutionRequestPopulator
     @Requirement
     private RepositorySystem repositorySystem;
 
+    @Override
     public MavenExecutionRequest populateFromSettings( MavenExecutionRequest request, Settings settings )
         throws MavenExecutionRequestPopulationException
     {
@@ -134,6 +140,29 @@ public class DefaultMavenExecutionRequestPopulator
         return request;
     }
 
+    @Override
+    public MavenExecutionRequest populateFromToolchains( MavenExecutionRequest request, PersistedToolchains toolchains )
+        throws MavenExecutionRequestPopulationException
+    {
+        if ( toolchains != null )
+        {
+            Map<String, List<ToolchainModel>> groupedToolchains = new HashMap<String, List<ToolchainModel>>( 2 );
+
+            for ( ToolchainModel model : toolchains.getToolchains() )
+            {
+                if ( !groupedToolchains.containsKey( model.getType() ) )
+                {
+                    groupedToolchains.put( model.getType(), new ArrayList<ToolchainModel>() );
+                }
+
+                groupedToolchains.get( model.getType() ).add( model );
+            }
+
+            request.setToolchains( groupedToolchains );
+        }
+        return request;
+    }
+    
     private void populateDefaultPluginGroups( MavenExecutionRequest request )
     {
         request.addPluginGroup( "org.apache.maven.plugins" );

maven-core/src/main/java/org/apache/maven/execution/MavenExecutionRequest.java

@@ -22,6 +22,7 @@ package org.apache.maven.execution;
 import java.io.File;
 import java.util.Date;
 import java.util.List;
+import java.util.Map;
 import java.util.Properties;
 
 import org.apache.maven.artifact.repository.ArtifactRepository;
@@ -31,6 +32,7 @@ import org.apache.maven.project.ProjectBuildingRequest;
 import org.apache.maven.settings.Mirror;
 import org.apache.maven.settings.Proxy;
 import org.apache.maven.settings.Server;
+import org.apache.maven.toolchain.model.ToolchainModel;
 import org.codehaus.plexus.logging.Logger;
 import org.eclipse.aether.RepositoryCache;
 import org.eclipse.aether.repository.WorkspaceReader;
@@ -394,4 +396,19 @@ public interface MavenExecutionRequest
      */
     String getBuilderId();
 
+    /**
+     * 
+     * @param toolchains all toolchains grouped by type 
+     * @return this request 
+     * @since 3.2.6
+     */
+    MavenExecutionRequest setToolchains( Map<String, List<ToolchainModel>> toolchains );
+    
+    /**
+     * 
+     * @return all toolchains grouped by type, never {@code null}
+     * @since 3.2.6
+     */
+    Map<String, List<ToolchainModel>> getToolchains();
+
 }

maven-core/src/main/java/org/apache/maven/execution/MavenExecutionRequestPopulator.java

@@ -20,6 +20,7 @@ package org.apache.maven.execution;
  */
 
 import org.apache.maven.settings.Settings;
+import org.apache.maven.toolchain.model.PersistedToolchains;
 
 /**
  * Assists in populating an execution request for invocation of Maven.
@@ -42,6 +43,20 @@ public interface MavenExecutionRequestPopulator
     MavenExecutionRequest populateFromSettings( MavenExecutionRequest request, Settings settings )
         throws MavenExecutionRequestPopulationException;
 
+    /**
+     * Copies the values from the given toolchains into the specified execution request. This method will replace any
+     * existing values in the execution request that are controlled by the toolchains. Hence, it is expected that this
+     * method is called on a new/empty execution request before the caller mutates it to fit its needs.
+     *
+     * @param request The execution request to populate, must not be {@code null}.
+     * @param toolchains The toolchains to copy into the execution request, may be {@code null}.
+     * @return The populated execution request, never {@code null}.
+     * @throws MavenExecutionRequestPopulationException If the execution request could not be populated.
+     * @since 3.2.6
+     */
+    MavenExecutionRequest populateFromToolchains( MavenExecutionRequest request, PersistedToolchains toolchains )
+        throws MavenExecutionRequestPopulationException;
+
     /**
      * Injects default values like plugin groups or repositories into the specified execution request.
      *

maven-embedder/src/main/java/org/apache/maven/cli/MavenCli.java

@@ -37,6 +37,8 @@ import org.apache.commons.cli.UnrecognizedOptionException;
 import org.apache.maven.BuildAbort;
 import org.apache.maven.InternalErrorException;
 import org.apache.maven.Maven;
+import org.apache.maven.building.FileSource;
+import org.apache.maven.building.Problem;
 import org.apache.maven.building.Source;
 import org.apache.maven.cli.event.DefaultEventSpyContext;
 import org.apache.maven.cli.event.ExecutionEventLogger;
@@ -66,7 +68,11 @@ import org.apache.maven.settings.building.SettingsBuilder;
 import org.apache.maven.settings.building.SettingsBuildingRequest;
 import org.apache.maven.settings.building.SettingsBuildingResult;
 import org.apache.maven.settings.building.SettingsProblem;
+import org.apache.maven.toolchain.MisconfiguredToolchainException;
+import org.apache.maven.toolchain.building.DefaultToolchainsBuildingRequest;
 import org.apache.maven.toolchain.building.ToolchainsBuilder;
+import org.apache.maven.toolchain.building.ToolchainsBuildingException;
+import org.apache.maven.toolchain.building.ToolchainsBuildingResult;
 import org.codehaus.plexus.ContainerConfiguration;
 import org.codehaus.plexus.DefaultContainerConfiguration;
 import org.codehaus.plexus.DefaultPlexusContainer;
@@ -445,6 +451,8 @@ public class MavenCli
 
         settingsBuilder = container.lookup( SettingsBuilder.class );
 
+        toolchainsBuilder = container.lookup( ToolchainsBuilder.class );
+
         dispatcher = (DefaultSecDispatcher) container.lookup( SecDispatcher.class, "maven" );
 
         return container;
@@ -838,17 +846,59 @@ public class MavenCli
         cliRequest.request.setGlobalToolchainsFile( globalToolchainsFile );
         cliRequest.request.setUserToolchainsFile( userToolchainsFile );
 
-        // Unlike settings, the toolchains aren't built here. 
-        // That's done by the maven-toolchains-plugin, by calling it from the project with the proper configuration
+        DefaultToolchainsBuildingRequest toolchainsRequest = new DefaultToolchainsBuildingRequest();
+        if ( globalToolchainsFile.isFile() )
+        {
+            toolchainsRequest.setGlobalToolchainsSource( new FileSource( globalToolchainsFile ) );
+        }
+        if ( userToolchainsFile.isFile() )
+        {
+            toolchainsRequest.setUserToolchainsSource( new FileSource( userToolchainsFile ) );
+        }
+
+        eventSpyDispatcher.onEvent( toolchainsRequest );
+
+        slf4jLogger.debug( "Reading global toolchains from "
+            + getLocation( toolchainsRequest.getGlobalToolchainsSource(), globalToolchainsFile ) );
+        slf4jLogger.debug( "Reading user toolchains from "
+            + getLocation( toolchainsRequest.getUserToolchainsSource(), userToolchainsFile ) );
+
+        ToolchainsBuildingResult toolchainsResult;
+        try
+        {
+            toolchainsResult = toolchainsBuilder.build( toolchainsRequest );
+        }
+        catch ( ToolchainsBuildingException e )
+        {
+            throw new MisconfiguredToolchainException( e.getMessage(), e );
+        }
+
+        eventSpyDispatcher.onEvent( toolchainsRequest );
+
+        executionRequestPopulator.populateFromToolchains( cliRequest.request,
+                                                          toolchainsResult.getEffectiveToolchains() );
+
+        if ( !toolchainsResult.getProblems().isEmpty() && slf4jLogger.isWarnEnabled() )
+        {
+            slf4jLogger.warn( "" );
+            slf4jLogger.warn( "Some problems were encountered while building the effective toolchains" );
+
+            for ( Problem problem : toolchainsResult.getProblems() )
+            {
+                slf4jLogger.warn( problem.getMessage() + " @ " + problem.getLocation() );
+            }
+
+            slf4jLogger.warn( "" );
+        }
     }
 
-    private Object getLocation( Source source, File file )
+    private Object getLocation( Source source, File defaultLocation )
     {
         if ( source != null )
         {
             return source.getLocation();
         }
-        return file;
+        return defaultLocation;
     }
 
     private MavenExecutionRequest populateRequest( CliRequest cliRequest )