Revamp LAL_Refactor error reporting

We now publish diagnostics instead of just sending an error response
when a refactoring fails. This allows users to better understand
why the refactorings did not work.

The code has also been factorized between all the refactorings.

Tests have been adapated to new user-readable labels for each
refactoring command.

For eng/ide/ada_language_server#1149

Author: AnthonyLeonardoGracio

source/ada/lsp-ada_handlers-refactor-add_parameter.adb

@@ -24,11 +24,8 @@ with Libadalang.Analysis; use Libadalang.Analysis;
 with LAL_Refactor.Subprogram_Signature;
 use LAL_Refactor.Subprogram_Signature;
 
-with LSP.Common;
-with LSP.Messages.Client_Requests;
-with LSP.Lal_Utils;
-
 with VSS.Strings.Conversions;
+with LSP.Commands;
 
 package body LSP.Ada_Handlers.Refactor.Add_Parameter is
 
@@ -119,33 +116,27 @@ package body LSP.Ada_Handlers.Refactor.Add_Parameter is
       end return;
    end Create;
 
-   -------------
-   -- Execute --
-   -------------
+   --------------
+   -- Refactor --
+   --------------
 
-   overriding procedure Execute
+   overriding procedure Refactor
      (Self    : Command;
       Handler : not null access LSP.Server_Notification_Receivers.
         Server_Notification_Receiver'Class;
       Client : not null access LSP.Client_Message_Receivers.
         Client_Message_Receiver'Class;
-      Error : in out LSP.Errors.Optional_ResponseError)
+      Edits   : out LAL_Refactor.Refactoring_Edits)
    is
       use Langkit_Support.Slocs;
       use LAL_Refactor;
-      use LSP.Messages;
       use LSP.Types;
-      use VSS.Strings.Conversions;
 
       Message_Handler : LSP.Ada_Handlers.Message_Handler renames
         LSP.Ada_Handlers.Message_Handler (Handler.all);
       Context         : LSP.Ada_Contexts.Context renames
         Message_Handler.Contexts.Get (Self.Context_Id).all;
 
-      Apply           : Client_Requests.Workspace_Apply_Edit_Request;
-      Workspace_Edits : WorkspaceEdit renames Apply.params.edit;
-      Label           : Optional_Virtual_String renames Apply.params.label;
-
       function Analysis_Units return Analysis_Unit_Array is
         (Context.Analysis_Units);
       --  Provides the Context Analysis_Unit_Array to the Mode_Changer
@@ -162,44 +153,9 @@ package body LSP.Ada_Handlers.Refactor.Add_Parameter is
            New_Parameter =>
              VSS.Strings.Conversions.To_Unbounded_UTF_8_String
                (Self.New_Parameter));
-      Edits : constant LAL_Refactor.Refactoring_Edits :=
-        Adder.Refactor (Analysis_Units'Access);
-
    begin
-      if Edits = No_Refactoring_Edits then
-         Error :=
-           (Is_Set => True,
-            Value  =>
-              (code    => LSP.Errors.UnknownErrorCode,
-               message => VSS.Strings.Conversions.To_Virtual_String
-                 ("Failed to execute the Add Parameter refactoring."),
-               data    => <>));
-
-      else
-         Workspace_Edits :=
-           LSP.Lal_Utils.To_Workspace_Edit
-             (Edits               => Edits,
-              Resource_Operations => Message_Handler.Resource_Operations,
-              Versioned_Documents => Message_Handler.Versioned_Documents,
-              Document_Provider   => Message_Handler'Access);
-         Label :=
-           (Is_Set => True,
-            Value  => To_Virtual_String (Command'External_Tag));
-
-         Client.On_Workspace_Apply_Edit_Request (Apply);
-      end if;
-
-   exception
-      when E : others =>
-         LSP.Common.Log (Message_Handler.Trace, E);
-         Error :=
-           (Is_Set => True,
-            Value  =>
-              (code => LSP.Errors.UnknownErrorCode,
-               message => VSS.Strings.Conversions.To_Virtual_String
-                 ("Failed to execute the Add Parameter refactoring."),
-               data => <>));
-   end Execute;
+      Edits := Adder.Refactor (Analysis_Units'Access);
+   end Refactor;
 
    ----------------
    -- Initialize --

source/ada/lsp-ada_handlers-refactor-add_parameter.ads

@@ -20,16 +20,18 @@
 with Ada.Streams;
 
 with LSP.Client_Message_Receivers;
-with LSP.Commands;
 with LSP.Messages;
-with LSP.Errors;
 with LSP.JSON_Streams;
 
 with VSS.Strings;
 
 package LSP.Ada_Handlers.Refactor.Add_Parameter is
 
-   type Command is new LSP.Commands.Command with private;
+   type Command is new LSP.Ada_Handlers.Refactor.Command with private;
+
+   overriding function Name (Self : Command) return String
+   is
+      ("Add Parameter");
 
    procedure Append_Code_Action
      (Self                        : in out Command;
@@ -41,7 +43,7 @@ package LSP.Ada_Handlers.Refactor.Add_Parameter is
 
 private
 
-   type Command is new LSP.Commands.Command with record
+   type Command is new LSP.Ada_Handlers.Refactor.Command with record
       Context_Id                  : VSS.Strings.Virtual_String;
       Where                       : LSP.Messages.Location;
       New_Parameter               : VSS.Strings.Virtual_String;
@@ -55,13 +57,13 @@ private
    --  Reads JS and creates a new Command
 
    overriding
-   procedure Execute
+   procedure Refactor
      (Self    : Command;
       Handler : not null access
         LSP.Server_Notification_Receivers.Server_Notification_Receiver'Class;
       Client  : not null access
         LSP.Client_Message_Receivers.Client_Message_Receiver'Class;
-      Error  : in out LSP.Errors.Optional_ResponseError);
+      Edits   : out LAL_Refactor.Refactoring_Edits);
    --  Executes Self by computing the necessary refactorings
 
    procedure Initialize

source/ada/lsp-ada_handlers-refactor-change_parameter_mode.adb

@@ -22,12 +22,11 @@ with Libadalang.Common; use Libadalang.Common;
 
 with Laltools.Common; use Laltools.Common;
 
-with LSP.Common;
 with LSP.Messages;
-with LSP.Messages.Client_Requests;
 with LSP.Lal_Utils;
 
 with VSS.Strings.Conversions;
+with LSP.Commands;
 
 package body LSP.Ada_Handlers.Refactor.Change_Parameter_Mode is
 
@@ -234,23 +233,21 @@ package body LSP.Ada_Handlers.Refactor.Change_Parameter_Mode is
       end return;
    end Create;
 
-   -------------
-   -- Execute --
-   -------------
+   --------------
+   -- Refactor --
+   --------------
 
    overriding
-   procedure Execute
+   procedure Refactor
      (Self    : Command;
       Handler : not null access LSP.Server_Notification_Receivers.
         Server_Notification_Receiver'Class;
       Client : not null access LSP.Client_Message_Receivers.
         Client_Message_Receiver'Class;
-      Error : in out LSP.Errors.Optional_ResponseError)
+      Edits   : out LAL_Refactor.Refactoring_Edits)
    is
       use LAL_Refactor;
-      use LSP.Messages;
       use LSP.Types;
-      use VSS.Strings.Conversions;
 
       Message_Handler : LSP.Ada_Handlers.Message_Handler renames
         LSP.Ada_Handlers.Message_Handler (Handler.all);
@@ -260,10 +257,6 @@ package body LSP.Ada_Handlers.Refactor.Change_Parameter_Mode is
       Document : constant LSP.Ada_Documents.Document_Access :=
         Message_Handler.Get_Open_Document (Self.Where.textDocument.uri);
 
-      Apply           : Client_Requests.Workspace_Apply_Edit_Request;
-      Workspace_Edits : WorkspaceEdit renames Apply.params.edit;
-      Label           : Optional_Virtual_String renames Apply.params.label;
-
       Node : constant Ada_Node :=
         Document.Get_Node_At (Context, Self.Where.position);
 
@@ -274,7 +267,6 @@ package body LSP.Ada_Handlers.Refactor.Change_Parameter_Mode is
          Last  => Positive (Self.Last_Param_Index));
 
       Changer : Mode_Changer;
-      Edits   : LAL_Refactor.Refactoring_Edits;
 
       function Analysis_Units return Analysis_Unit_Array is
         (Context.Analysis_Units);
@@ -304,14 +296,14 @@ package body LSP.Ada_Handlers.Refactor.Change_Parameter_Mode is
 
    begin
       if Target_Subp.Is_Null then
-         Error :=
-           (Is_Set => True,
-            Value  =>
-              (code    => LSP.Errors.InvalidRequest,
-               message => VSS.Strings.To_Virtual_String
-                 ("Could not execute Change Parameter Mode command. "
-                  & "The target subprogram could not be resolved precisely."),
-               data    => <>));
+         Edits :=
+           (Diagnostics =>
+              [LAL_Refactor.Subprogram_Signature.Create
+                   (Subp => Node,
+                    Info => VSS.Strings.To_Virtual_String
+                      ("The target subprogram could "
+                       & "not be resolved precisely."))],
+            others      => <>);
          return;
       end if;
 
@@ -321,41 +313,7 @@ package body LSP.Ada_Handlers.Refactor.Change_Parameter_Mode is
          Value (Self.New_Mode));
 
       Edits := Changer.Refactor (Analysis_Units'Access);
-
-      if Edits = No_Refactoring_Edits then
-         Error :=
-           (Is_Set => True,
-            Value  =>
-              (code    => LSP.Errors.UnknownErrorCode,
-               message => VSS.Strings.Conversions.To_Virtual_String
-                 ("Failed to execute the Change Parameter Mode refactoring."),
-               data    => <>));
-
-      else
-         Workspace_Edits :=
-           LSP.Lal_Utils.To_Workspace_Edit
-             (Edits               => Edits,
-              Resource_Operations => Message_Handler.Resource_Operations,
-              Versioned_Documents => Message_Handler.Versioned_Documents,
-              Document_Provider   => Message_Handler'Access);
-         Label :=
-           (Is_Set => True,
-            Value  => To_Virtual_String (Command'External_Tag));
-
-         Client.On_Workspace_Apply_Edit_Request (Apply);
-      end if;
-
-   exception
-      when E : others =>
-         LSP.Common.Log (Message_Handler.Trace, E);
-         Error :=
-           (Is_Set => True,
-            Value  =>
-              (code => LSP.Errors.UnknownErrorCode,
-               message => VSS.Strings.Conversions.To_Virtual_String
-                 ("Failed to execute the Change Parameter Mode refactoring."),
-               data => <>));
-   end Execute;
+   end Refactor;
 
    ----------------
    -- Initialize --

source/ada/lsp-ada_handlers-refactor-change_parameter_mode.ads

@@ -22,8 +22,6 @@ with Ada.Streams;
 private with VSS.Strings;
 
 with LSP.Client_Message_Receivers;
-with LSP.Commands;
-with LSP.Errors;
 with LSP.JSON_Streams;
 
 with Libadalang.Analysis;
@@ -33,7 +31,11 @@ with LAL_Refactor.Subprogram_Signature; use LAL_Refactor.Subprogram_Signature;
 
 package LSP.Ada_Handlers.Refactor.Change_Parameter_Mode is
 
-   type Command is new LSP.Commands.Command with private;
+   type Command is new LSP.Ada_Handlers.Refactor.Command with private;
+
+      overriding function Name (Self : Command) return String
+   is
+      ("Change Parameter Mode");
 
    procedure Append_Code_Action
      (Self               : in out Command;
@@ -46,7 +48,7 @@ package LSP.Ada_Handlers.Refactor.Change_Parameter_Mode is
 
 private
 
-   type Command is new LSP.Commands.Command with record
+   type Command is new LSP.Ada_Handlers.Refactor.Command with record
       Context           : VSS.Strings.Virtual_String;
       Where             : LSP.Messages.TextDocumentPositionParams;
       First_Param_Index : LSP.Types.LSP_Number;
@@ -61,13 +63,13 @@ private
    --  Reads JS and creates a new Command
 
    overriding
-   procedure Execute
+   procedure Refactor
      (Self    : Command;
       Handler : not null access
         LSP.Server_Notification_Receivers.Server_Notification_Receiver'Class;
       Client  : not null access
         LSP.Client_Message_Receivers.Client_Message_Receiver'Class;
-      Error   : in out LSP.Errors.Optional_ResponseError);
+      Edits   : out LAL_Refactor.Refactoring_Edits);
    --  Executes Self by computing the necessary refactorings
 
    procedure Initialize