Use fallback indenter for textDocument/onTypeFormatting

For eng/ide/ada_language_server#1529

Author: AnthonyLeonardoGracio

source/ada/lsp-ada_handlers-formatting.adb

@@ -33,14 +33,6 @@ package body LSP.Ada_Handlers.Formatting is
      "GNATformat: Syntactically invalid code can't be formatted";
    --  Error message sent when trying to format invalid code.
 
-   function Reindent_Line
-     (Filename   : GNATCOLL.VFS.Virtual_File;
-      Line       : VSS.Strings.Virtual_String;
-      Options    : Gnatformat.Configuration.Format_Options_Type;
-      Pos        : LSP.Structures.Position;
-      New_Indent : Natural) return LSP.Structures.TextEdit;
-   --  Generate a textEdit to reindent the current line
-
    -------------------
    -- Reindent_Line --
    -------------------

source/ada/lsp-ada_handlers-formatting.ads

@@ -88,6 +88,18 @@ package LSP.Ada_Handlers.Formatting is
    --  Messages contains any informational or warning messages.
    --  Error is set if an error occurred.
 
+   function Reindent_Line
+     (Filename   : GNATCOLL.VFS.Virtual_File;
+      Line       : VSS.Strings.Virtual_String;
+      Options    : Gnatformat.Configuration.Format_Options_Type;
+      Pos        : LSP.Structures.Position;
+      New_Indent : Natural) return LSP.Structures.TextEdit;
+   --  Reindent a line to the given new indentation.
+   --  Line contains the actual line in the document.
+   --  Options are the formatting options to handle tabs/spaces.
+   --  Pos is the LSP position of the line in the document.
+   --  New_Indent is the new indentation level for the line.
+
    function Handle_Tabs
      (Filename : GNATCOLL.VFS.Virtual_File;
       Options  : Gnatformat.Configuration.Format_Options_Type;

source/gpr/lsp-gpr_handlers.adb

@@ -28,6 +28,7 @@ with LSP.Ada_Handlers.Formatting;
 with LSP.Constants;
 with LSP.Enumerations;
 with LSP.Errors;
+with LSP.Formatters.Fallback_Indenter;
 with LSP.Generic_Cancel_Check;
 with LSP.GPR_Completions;
 with LSP.GPR_Documentation;
@@ -39,6 +40,7 @@ with LSP.Text_Documents.Langkit_Documents;
 with LSP.Utils;
 
 with Gpr_Parser.Common;
+with VSS.Characters.Latin;
 with VSS.String_Vectors;
 with VSS.Strings;
 
@@ -409,7 +411,7 @@ package body LSP.GPR_Handlers is
       Response     : LSP.Structures.InitializeResult;
       Capabilities : LSP.Structures.ServerCapabilities renames
         Response.capabilities;
-
+      use VSS.Strings;
    begin
       Self.File_Reader := LSP.GPR_File_Readers.Create (Self'Unchecked_Access);
 
@@ -446,6 +448,11 @@ package body LSP.GPR_Handlers is
         (Is_Set => True, Value => (Is_Boolean => True, Boolean => True));
       Capabilities.documentFormattingProvider :=
         (Is_Set => True, Value => (Is_Boolean => True, Boolean => True));
+      Capabilities.documentOnTypeFormattingProvider :=
+        (Is_Set => True,
+         Value  =>
+           (firstTriggerCharacter => 1 * VSS.Characters.Latin.Line_Feed,
+            moreTriggerCharacter  => <>));
 
       Capabilities.textDocumentSync :=
         (Is_Set => True,
@@ -628,6 +635,76 @@ package body LSP.GPR_Handlers is
       end if;
    end On_RangeFormatting_Request;
 
+   ---------------------------------
+   -- On_OnTypeFormatting_Request --
+   ---------------------------------
+
+   overriding
+   procedure On_OnTypeFormatting_Request
+     (Self  : in out Message_Handler;
+      Id    : LSP.Structures.Integer_Or_Virtual_String;
+      Value : LSP.Structures.DocumentOnTypeFormattingParams)
+   is
+      use VSS.Strings;
+      Response : LSP.Structures.TextEdit_Vector_Or_Null;
+      Document : constant LSP.GPR_Documents.Document_Access :=
+        Self.Get_Open_Document (Value.textDocument.uri);
+      Options  : constant Gnatformat.Configuration.Format_Options_Type :=
+        Gnatformat.Configuration.Default_Format_Options;
+
+      Filename : constant GNATCOLL.VFS.Virtual_File :=
+        Self.To_File (Value.textDocument.uri);
+
+      Indent_Array :
+        constant LSP.Formatters.Fallback_Indenter.Indentation_Array :=
+          LSP.Ada_Handlers.Formatting.Get_Indentation
+            (Filename => Filename,
+             Buffer   =>
+               Document.Slice (((0, 0), (Value.position.line + 1, 0))),
+             Span     =>
+               ((0, 0), (Value.position.line + 1, 0)),
+             Options  => Options);
+      Indentation  : constant VSS.Strings.Character_Count :=
+        (if Indent_Array (Value.position.line + 1) = -1
+         then 0
+         else
+           VSS.Strings.Character_Count
+             (Indent_Array (Value.position.line + 1)));
+   begin
+      --  First set the indentation for the new line
+      Response.Append
+        (LSP.Structures.TextEdit'
+           (a_range =>
+              (start => (Value.position.line, 0), an_end => Value.position),
+            newText =>
+              LSP.Ada_Handlers.Formatting.Handle_Tabs
+                (Filename => Filename,
+                 Options  => Options,
+                 S        => Indentation * ' ')));
+
+      --  If not in indent-only mode, re-indent the previous line too
+      if not Self.Configuration.Indent_Only then
+         declare
+            Prev_Line             : constant Natural :=
+              Natural'Max (Value.position.line - 1, 0);
+            Indentation : constant Natural :=
+              (if Indent_Array (Prev_Line + 1) = -1
+               then 0
+               else Indent_Array (Prev_Line + 1));
+         begin
+            Response.Append
+              (LSP.Ada_Handlers.Formatting.Reindent_Line
+                 (Filename   => Filename,
+                  Line       => Document.Get_Line (Prev_Line),
+                  Pos        => (Prev_Line, 0),
+                  Options    => Options,
+                  New_Indent => Indentation));
+         end;
+      end if;
+
+      Self.Sender.On_OnTypeFormatting_Response (Id, Response);
+   end On_OnTypeFormatting_Request;
+
    ---------------------------
    -- On_Completion_Request --
    ---------------------------

source/gpr/lsp-gpr_handlers.ads

@@ -176,6 +176,12 @@ private
       Id    : LSP.Structures.Integer_Or_Virtual_String;
       Value : LSP.Structures.DocumentRangeFormattingParams);
 
+   overriding
+   procedure On_OnTypeFormatting_Request
+     (Self  : in out Message_Handler;
+      Id    : LSP.Structures.Integer_Or_Virtual_String;
+      Value : LSP.Structures.DocumentOnTypeFormattingParams);
+
    overriding procedure On_Completion_Request
      (Self  : in out Message_Handler;
       Id    : LSP.Structures.Integer_Or_Virtual_String;

testsuite/drivers/lsp_ada_requests.py

@@ -247,12 +247,16 @@ class IndentationTestCase:
             where the line break occurs.
         expected_indentation (str): The expected indentation string after the
             onTypeFormatting request is applied.
+        additional_text_edits (List[TextEdit]): A list of additional TextEdit
+            objects that represent other expected changes in the source code
+            (e.g: a TextEdit on the previous line when indentOnly is False).
     """
 
     description: str
     source_filename: str
     line_break_position: Position
     expected_indentation: str
+    additional_text_edits: List[TextEdit] = []
 
     @property
     def change_range(self) -> Range:
@@ -288,7 +292,7 @@ def expected_text_edits(self) -> List[TextEdit]:
                 ),
                 self.expected_indentation,
             )
-        ]
+        ] + self.additional_text_edits
 
 
 async def run_indentation_testcases(lsp, testcases, options):

testsuite/gpr_lsp/on_type_formatting/test.gpr

@@ -0,0 +1,8 @@
+project Test is
+
+   package Compiler is
+      for Default_Switches ("ada") use ("-gnat2022", "-O0", "-g", "-fdiagnostics-color=never");
+      end Compiler;
+
+end Test;
+

testsuite/gpr_lsp/on_type_formatting/test.py

@@ -0,0 +1,97 @@
+"""Test the textDocument/onTypeFormatting request on GPR files"""
+
+import os
+from drivers.pylsp import (
+    URI,
+    ALSClientServerConfig,
+    ALSLanguageClient,
+    OnTypeFormattingSetting,
+    test,
+)
+from drivers.lsp_ada_requests import (
+    IndentationTestCase,
+    run_indentation_testcases,
+)
+from lsprotocol.types import (
+    ClientCapabilities,
+    DocumentOnTypeFormattingOptions,
+    FormattingOptions,
+    InitializedParams,
+    InitializeParams,
+    Position,
+    Range,
+    TextEdit,
+)
+
+
+@test(
+    config=ALSClientServerConfig(
+        [
+            os.environ.get("ALS", "ada_language_server"),
+            "--language-gpr",
+        ]
+    ),
+)
+async def test_on_type_formatting_indentation(lsp: ALSLanguageClient) -> None:
+    """
+    Test the onTypeFormatting feature on GPR files.
+
+    This test verifies that ALS correctly estimates the indentation that should
+    be added after a line break.
+
+    Tests should be added to the indentation_tests list.
+    """
+
+    # Send the initialize request
+
+    response = await lsp.initialize_session(
+        InitializeParams(
+            capabilities=ClientCapabilities(),
+            root_uri=URI(os.getcwd()),
+            initialization_options={
+                "ada": {"onTypeFormatting": OnTypeFormattingSetting(indentOnly=False)}
+            },
+        )
+    )
+
+    # Verify that the right capability is advertised
+
+    lsp.assertEqual(
+        response.capabilities.document_on_type_formatting_provider,
+        DocumentOnTypeFormattingOptions(
+            first_trigger_character="\n", more_trigger_character=None
+        ),
+    )
+
+    # Send the initialized notification and the didChangeConfiguration
+    # notification, configuring ALS to only indent when it receives an
+    # onTypeFormattingRequest
+
+    lsp.initialized(InitializedParams())
+
+    # Test list
+    indentation_tests = [
+        IndentationTestCase(
+            "Indentation after for inside package",
+            "test.gpr",
+            Position(3, 95),
+            "      ",
+            [TextEdit(Range(Position(3, 0), Position(3, 6)), new_text="      ")],
+        ),
+        IndentationTestCase(
+            "Indentation after end of package",
+            "test.gpr",
+            Position(4, 18),
+            "   ",
+            [TextEdit(Range(Position(4, 0), Position(4, 6)), new_text="   ")],
+        ),
+    ]
+
+    failed_tests = await run_indentation_testcases(
+        lsp, indentation_tests, FormattingOptions(tab_size=3, insert_spaces=False)
+    )
+
+    if len(failed_tests) > 0:
+        fail_messages = "\n\n".join(failed_tests)
+        message = f"Indentation tests failed\n\n{fail_messages}"
+        raise Exception(message)  # pylint: disable=broad-exception-raised

testsuite/gpr_lsp/on_type_formatting/test.yaml

@@ -0,0 +1 @@
+driver: pylsp