Handle exceptions in Project_Tree.Update_Sources

and report as errors. Add the test case.

Author: reznikmm

source/ada/lsp-ada_handlers.adb

@@ -5016,6 +5016,8 @@ package body LSP.Ada_Handlers is
             Build_Path  => Self.Project_Environment.Build_Path,
             Environment => Environment);
 
+         Self.Project_Tree.Update_Sources (With_Runtime => True);
+
       exception
          when E : GPR2.Project_Error
                 | GPR2.Processing_Error
@@ -5045,7 +5047,6 @@ package body LSP.Ada_Handlers is
             Self.Project_Status := No_Runtime_Found;
          end if;
 
-         Self.Project_Tree.Update_Sources (With_Runtime => True);
          Update_Project_Predefined_Sources (Self);
 
          if Self.Project_Tree.Root_Project.Kind in GPR2.Aggregate_Kind then

testsuite/ada_lsp/project_config.missing_file/main.adb

@@ -0,0 +1,4 @@
+procedure Main is
+begin
+   null;
+end Main;

testsuite/ada_lsp/project_config.missing_file/prj1.gpr

@@ -0,0 +1,4 @@
+project Prj1 is
+   for Source_Files use ("missing.ads", "main.adb");
+end Prj1;
+

testsuite/ada_lsp/project_config.missing_file/test.json

@@ -0,0 +1,113 @@
+[
+    {
+        "comment":[
+            "This test check language server is able to report errors",
+            "when loading a project with missing files."
+        ]
+    },  {
+        "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,
+                        "definitionProvider":true
+                    }
+                }
+            }]
+        }
+    },  {
+        "send": {
+            "request": {
+                "jsonrpc":"2.0",
+                "method":"workspace/didChangeConfiguration",
+                "params":{
+                    "settings":{
+                        "ada":{
+                            "projectFile": "prj1.gpr"
+                        }
+                    }
+                }
+            },
+            "wait":[
+		{
+		    "jsonrpc": "2.0",
+		    "method": "window/showMessage",
+		    "params": {
+			"type": 1,
+			"message": "<ANY>"
+		    }
+		}
+	    ]
+        }
+    },  {
+        "send": {
+            "request": {
+                "jsonrpc":"2.0",
+                "method":"textDocument/didOpen",
+                "params":{
+                    "textDocument": {
+                        "uri": "$URI{main.adb}",
+                        "languageId": "ada",
+                        "version": 1,
+                        "text": "procedure Main is\nbegin\n   null;\nend Main;"
+                    }
+                }
+            },
+            "wait":[
+		{
+		    "jsonrpc": "2.0",
+		    "method": "textDocument/publishDiagnostics",
+		    "params": {
+			"uri":"$URI{main.adb}",
+			"diagnostics":[
+			    {
+				"range": {
+				    "start": {
+					"line": 0,
+					"character": 0
+				    },
+				    "end": {
+					"line":0,
+					"character":0
+				    }
+				},
+				"severity": 1,
+				"source": "project",
+				"message": "Project file has error and can't be loaded."
+			    }
+			]
+		    }
+		}
+	    ]
+        }
+    },  {
+        "send": {
+            "request": {
+                "jsonrpc":"2.0",
+                "id": "shutdown",
+                "method":"shutdown",
+                "params":null
+            },
+            "wait":[{ "id": "shutdown", "result": null }]
+        }
+    },  {
+        "send": {
+            "request": {"jsonrpc":"2.0", "method":"exit", "params":{}},
+            "wait":[]
+        }
+    }, {
+        "stop": {
+            "exit_code": 0
+        }
+    }
+]

testsuite/ada_lsp/project_config.missing_file/test.yaml

@@ -0,0 +1 @@
+title: 'project_config.missing_file'