Fix als-other-file command for child packages

For this command, we were  calling Unit which expects an unit name
but we were passing a file base name (without extension).

So this doesn't work if the file base name contains '-'
(child packages).

Use the proper GPR2 API to get a proper unit name instead.

Add an automatic test.

For eng/ide/ada_language_server#1450

source/ada/lsp-ada_handlers-other_file_commands.adb

@@ -15,6 +15,8 @@
 -- of the license.                                                          --
 ------------------------------------------------------------------------------
 
+with GPR2.Build.Unit_Info;
+with GPR2.Project.View;
 with VSS.JSON.Streams;
 
 with GNATCOLL.VFS; use GNATCOLL.VFS;
@@ -126,20 +128,27 @@ package body LSP.Ada_Handlers.Other_File_Commands is
          -- Unit_For_File --
          -------------------
 
-         function Unit_For_File return GPR2.Build.Compilation_Unit.Object
-         is
-            Unit : GPR2.Build.Compilation_Unit.Object;
+         function Unit_For_File return GPR2.Build.Compilation_Unit.Object is
          begin
-            --  First look in the closure of sources, then in the
-            --  runtime project.
+            --  Check in the root project's closure for a visible source
+            --  corresponding to this file.
+            --  Not that the root's project closure includes the runtime.
             if Handler.Project_Tree.Is_Defined then
-               Unit := Handler.Project_Tree.Root_Project.Unit (F.Base_Name);
+               declare
+                  View      : constant GPR2.Project.View.Object :=
+                    Handler.Project_Tree.Root_Project;
+                  Unit_Info : constant GPR2.Build.Unit_Info.Object :=
+                    View.Visible_Source (F.Simple_Name).Unit;
+                  Unit      : GPR2.Build.Compilation_Unit.Object :=
+                    GPR2.Build.Compilation_Unit.Undefined;
+               begin
+                  if Unit_Info.Is_Defined then
+                     Unit := View.Namespace_Roots.First_Element.Unit
+                       (Unit_Info.Name);
+                  end if;
 
-               if not Unit.Is_Defined then
-                  Unit := Handler.Project_Tree.Runtime_Project.Unit
-                    (F.Base_Name);
-               end if;
-               return Unit;
+                  return Unit;
+               end;
             else
                return GPR2.Build.Compilation_Unit.Undefined;
             end if;

testsuite/ada_lsp/commands.other_file.child_packages/a-b.adb

@@ -0,0 +1,8 @@
+package body A.B is
+   procedure Proc (X : in out Integer) is
+   begin
+      X := X + 2 * X;
+
+      Proc (X => X);
+   end Proc;
+end A.B;

testsuite/ada_lsp/commands.other_file.child_packages/a-b.ads

@@ -0,0 +1,3 @@
+package A.B is
+   procedure Proc (X : in out Integer);
+end A.B;

testsuite/ada_lsp/commands.other_file.child_packages/a.ads

@@ -0,0 +1,2 @@
+package A with Pure is
+end A;

testsuite/ada_lsp/commands.other_file.child_packages/default.gpr

@@ -0,0 +1,2 @@
+project Default is
+end Default;

testsuite/ada_lsp/commands.other_file.child_packages/test.json

@@ -0,0 +1,163 @@
+[
+   {
+      "comment": "Check that the 'als-other-file' command works fine with child packages"
+   },
+   {
+      "start": {
+         "cmd": ["${ALS}"]
+      }
+   },
+   {
+      "send": {
+         "request": {
+            "jsonrpc": "2.0",
+            "id": 0,
+            "method": "initialize",
+            "params": {
+               "processId": 1,
+               "rootUri": "$URI{.}",
+               "capabilities": {}
+            }
+         },
+         "wait": [
+            {
+               "id": 0,
+               "result": {
+                  "capabilities": {
+                     "textDocumentSync": 2,
+                     "executeCommandProvider": {
+                        "commands": ["<HAS>", "als-other-file"]
+                     }
+                  }
+               }
+            }
+         ]
+      }
+   },
+   {
+      "send": {
+         "request": {
+            "jsonrpc": "2.0",
+            "method": "workspace/didChangeConfiguration",
+            "params": {
+               "settings": {
+                  "ada": {}
+               }
+            }
+         },
+         "wait": [
+            {
+               "jsonrpc": "2.0",
+               "id": 1,
+               "method": "window/workDoneProgress/create",
+               "params": {
+                  "token": "<ANY>"
+               }
+            }
+         ]
+      }
+   },
+   {
+      "send": {
+         "request": {
+            "jsonrpc": "2.0",
+            "method": "textDocument/didOpen",
+            "params": {
+               "textDocument": {
+                  "uri": "$URI{a-b.ads}",
+                  "languageId": "ada",
+                  "version": 1,
+                  "text": "package A.B is\n   procedure Proc (X : in out Integer);\nend A.B;\n"
+               }
+            }
+         },
+         "wait": []
+      }
+   },
+   {
+      "send": {
+         "request": {
+            "jsonrpc": "2.0",
+            "id": "sw1",
+            "method": "workspace/executeCommand",
+            "params": {
+               "command": "als-other-file",
+               "arguments": [
+                  {
+                     "uri": "$URI{a-b.ads}"
+                  }
+               ]
+            }
+         },
+         "wait": [
+            {
+               "jsonrpc": "2.0",
+               "method": "window/showDocument",
+               "params": {
+                  "uri": "$URI{a-b.adb}",
+                  "takeFocus": true
+               }
+            },
+            {
+               "jsonrpc": "2.0",
+               "id": "sw1",
+               "result": null
+            }
+         ]
+      }
+   },
+   {
+      "send": {
+         "request": {
+            "jsonrpc": "2.0",
+            "id": "sw2",
+            "method": "workspace/executeCommand",
+            "params": {
+               "command": "als-other-file",
+               "arguments": [
+                  {
+                     "uri": "$URI{a-b.adb}"
+                  }
+               ]
+            }
+         },
+         "wait": [
+            {
+               "jsonrpc": "2.0",
+               "method": "window/showDocument",
+               "params": {
+                  "uri": "$URI{a-b.ads}",
+                  "takeFocus": true
+               }
+            },
+            {
+               "jsonrpc": "2.0",
+               "id": "sw2",
+               "result": null
+            }
+         ]
+      }
+   },
+   {
+      "send": {
+         "request": {
+            "jsonrpc": "2.0",
+            "id": "shutdown",
+            "method": "shutdown",
+            "params": null
+         },
+         "wait": [{ "id": "shutdown", "result": null }]
+      }
+   },
+   {
+      "send": {
+         "request": { "jsonrpc": "2.0", "method": "exit" },
+         "wait": []
+      }
+   },
+   {
+      "stop": {
+         "exit_code": 0
+      }
+   }
+]

testsuite/ada_lsp/commands.other_file.child_packages/test.yaml

@@ -0,0 +1 @@
+title: 'commands.other_file'