Change from "sln" to "solution" as primary, and add "sln" as alias

src/BuiltInTools/dotnet-watch/CommandLineOptions.cs

@@ -34,7 +34,7 @@ internal sealed class CommandLineOptions
         "restore",
         "run",
         "sdk",
-        "sln",
+        "solution",
         "store",
         "test",
         "tool",
@@ -179,7 +179,7 @@ internal sealed class CommandLineOptions
             BuildProperties = ParseBuildProperties(parseResult.GetValue(propertyOption) ?? []).ToArray(),
         };
 
-        // Parses name=value pairs passed to --property. Skips invalid input. 
+        // Parses name=value pairs passed to --property. Skips invalid input.
         // We don't report error here as it will be reported by dotnet run.
         static IEnumerable<(string key, string value)> ParseBuildProperties(string[] properties)
             => from property in properties
@@ -240,7 +240,7 @@ private static IReadOnlyList<string> GetCommandArguments(
             {
                 explicitCommand = token;
             }
-            else 
+            else
             {
                 if (!dashDashInserted && i >= unmatchedTokensBeforeDashDash)
                 {

src/Cli/dotnet-new3/Dotnet.cs

@@ -72,7 +72,7 @@ internal static Dotnet AddProjectsToSolution(string solutionFile, IReadOnlyList<
         {
             List<string> allArgs = new()
             {
-                "sln",
+                "solution",
                 solutionFile,
                 "add"
             };

src/Cli/dotnet/ReleasePropertyProjectLocator.cs

@@ -138,7 +138,7 @@ public IEnumerable<string> GetCustomDefaultConfigurationValueIfSpecified()
                     }
                 }
             }
-            return null;  // If nothing can be found: that's caught by MSBuild XMake::ProcessProjectSwitch -- don't change the behavior by failing here. 
+            return null;  // If nothing can be found: that's caught by MSBuild XMake::ProcessProjectSwitch -- don't change the behavior by failing here.
         }
 
         /// <returns>An arbitrary existant project in a solution file. Returns null if no projects exist.
@@ -205,7 +205,7 @@ public IEnumerable<string> GetCustomDefaultConfigurationValueIfSpecified()
         /// <summary>
         /// Returns an arbitrary project for the solution. Relies on the .NET SDK PrepareForPublish or _VerifyPackReleaseConfigurations MSBuild targets to catch conflicting values of a given property, like PublishRelease or PackRelease.
         /// </summary>
-        /// <param name="sln">The solution to get an arbitrary project from.</param>
+        /// <param name="solution">The solution to get an arbitrary project from.</param>
         /// <param name="globalProps">The global properties to load into the project.</param>
         /// <returns>null if no project exists in the solution that can be evaluated properly. Else, the first project in the solution that can be.</returns>
         private ProjectInstance? GetSingleProjectFromSolution(SlnFile sln, Dictionary<string, string> globalProps)
@@ -253,13 +253,13 @@ private bool IsUnanalyzableProjectInSolution(SlnProject project, string projectF
             return null;
         }
 
-        /// <returns>Returns true if the path exists and is a project file type.</returns> 
+        /// <returns>Returns true if the path exists and is a project file type.</returns>
         private bool IsValidProjectFilePath(string path)
         {
             return File.Exists(path) && Path.GetExtension(path).EndsWith("proj");
         }
 
-        /// <returns>Returns true if the path exists and is a sln file type.</returns> 
+        /// <returns>Returns true if the path exists and is a sln file type.</returns>
         private bool IsValidSlnFilePath(string path)
         {
             return File.Exists(path) && Path.GetExtension(path).EndsWith("sln");
@@ -271,7 +271,7 @@ private Dictionary<string, string> GetUserSpecifiedExplicitMSBuildProperties()
             Dictionary<string, string> globalProperties = new(StringComparer.OrdinalIgnoreCase);
 
             string[]? globalPropEnumerable = _parseResult.GetValue(CommonOptions.PropertiesOption);
-            
+
             if ( globalPropEnumerable != null )
             {
                 foreach (var keyEqValString in globalPropEnumerable)

src/Cli/dotnet/Telemetry/TelemetryFilter.cs

@@ -84,7 +84,7 @@ public IEnumerable<ApplicationInsightsEntryFormat> Filter(object objectToFilter)
         private static List<IParseResultLogRule> ParseResultLogRules => new()
         {
             new AllowListToSendFirstArgument(new HashSet<string> {"new", "help"}),
-            new AllowListToSendFirstAppliedOptions(new HashSet<string> {"add", "remove", "list", "sln", "nuget"}),
+            new AllowListToSendFirstAppliedOptions(new HashSet<string> {"add", "remove", "list", "solution", "nuget"}),
             new TopLevelCommandNameAndOptionToLog
             (
                 topLevelCommandName: new HashSet<string> {"build", "publish"},

src/Cli/dotnet/commands/dotnet-help/HelpUsageText.cs

@@ -50,7 +50,7 @@ internal static class HelpUsageText
   restore           {LocalizableStrings.RestoreDefinition}
   run               {LocalizableStrings.RunDefinition}
   sdk               {LocalizableStrings.SdkDefinition}
-  sln               {LocalizableStrings.SlnDefinition}
+  solution          {LocalizableStrings.SlnDefinition}
   store             {LocalizableStrings.StoreDefinition}
   test              {LocalizableStrings.TestDefinition}
   tool              {LocalizableStrings.ToolDefinition}

src/Cli/dotnet/commands/dotnet-new/DotnetCommandCallbacks.cs

@@ -46,7 +46,7 @@ internal static bool AddProjectsToSolution(string solutionPath, IReadOnlyList<st
         {
             PathUtility.EnsureAllPathsExist(new[] { solutionPath }, CommonLocalizableStrings.FileNotFound, allowDirectories: false);
             PathUtility.EnsureAllPathsExist(projectsToAdd, CommonLocalizableStrings.FileNotFound, allowDirectories: false);
-            IEnumerable<string> commandArgs = new[] { "sln", solutionPath, "add" }.Concat(projectsToAdd);
+            IEnumerable<string> commandArgs = new[] { "solution", solutionPath, "add" }.Concat(projectsToAdd);
             if (!string.IsNullOrWhiteSpace(solutionFolder))
             {
                 commandArgs = commandArgs.Append(SlnAddParser.SolutionFolderOption.Name).Append(solutionFolder);

src/Cli/dotnet/commands/dotnet-sln/SlnArgumentValidator.cs

@@ -52,7 +52,7 @@ public static void ParseAndValidateArguments(string _fileOrDirectory, IReadOnlyC
                 {
                     string.Format(CommonLocalizableStrings.SolutionArgumentMisplaced, slnFile),
                     CommonLocalizableStrings.DidYouMean,
-                    $"  dotnet sln {slnFile} {command} {args}{projectArgs}"
+                    $"  dotnet solution {slnFile} {command} {args}{projectArgs}"
                 });
             }
         }

src/Cli/dotnet/commands/dotnet-sln/SlnCommandParser.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.CommandLine;
+using NuGet.Packaging;
 using LocalizableStrings = Microsoft.DotNet.Tools.Sln.LocalizableStrings;
 
 namespace Microsoft.DotNet.Cli
@@ -10,6 +11,8 @@ internal static class SlnCommandParser
     {
         public static readonly string DocsLink = "https://aka.ms/dotnet-sln";
 
+        public static readonly string CommandName = "solution";
+        public static readonly string CommandAlias = "sln";
         public static readonly CliArgument<string> SlnArgument = new CliArgument<string>(LocalizableStrings.SolutionArgumentName)
         {
             HelpName = LocalizableStrings.SolutionArgumentName,
@@ -26,7 +29,9 @@ public static CliCommand GetCommand()
 
         private static CliCommand ConstructCommand()
         {
-            DocumentedCommand command = new("sln", DocsLink, LocalizableStrings.AppFullName);
+            DocumentedCommand command = new(CommandName, DocsLink, LocalizableStrings.AppFullName);
+
+            command.Aliases.Add(CommandAlias);
 
             command.Arguments.Add(SlnArgument);
             command.Subcommands.Add(SlnAddParser.GetCommand());

test/dotnet-help.Tests/GivenThatIWantToShowHelpForDotnetCommand.cs

@@ -52,7 +52,7 @@ remove            Remove a package or reference from a .NET project.
   restore           Restore dependencies specified in a .NET project.
   run               Build and run a .NET project output.
   sdk               Manage .NET SDK installation.
-  sln               Modify Visual Studio solution files.
+  solution          Modify Visual Studio solution files.
   store             Store the specified assemblies in the runtime package store.
   test              Run unit tests using the test runner specified in a .NET project.
   tool              Install or manage tools that extend the .NET experience.