Fix loading of ALIRE project

For eng/ide/ada_language_server#1359

Author: eliericha

source/ada/lsp-ada_handlers-alire.adb

@@ -77,12 +77,11 @@ package body LSP.Ada_Handlers.Alire is
    -- Run_Alire --
    ---------------
 
-   procedure Run_Alire
+   procedure Determine_Alire_Project
      (Root        : String;
       Has_Alire   : out Boolean;
       Error       : out VSS.Strings.Virtual_String;
-      Project     : out VSS.Strings.Virtual_String;
-      Environment : in out GPR2.Environment.Object)
+      Project     : out VSS.Strings.Virtual_String)
    is
       use type GNAT.OS_Lib.String_Access;
 
@@ -96,10 +95,6 @@ package body LSP.Ada_Handlers.Alire is
         VSS.Regular_Expressions.To_Regular_Expression
           (" +Project_File: ([^\n]+)");
 
-      Export_Pattern : constant VSS.Regular_Expressions.Regular_Expression :=
-        VSS.Regular_Expressions.To_Regular_Expression
-          ("export ([^=]+)=""([^\n]+)""");
-
       Lines    : VSS.String_Vectors.Virtual_String_Vector;
    begin
       Project.Clear;
@@ -117,66 +112,64 @@ package body LSP.Ada_Handlers.Alire is
          return;
       end if;
 
-      --  Find project file in `alr show` output
-
-      declare
-         First : constant VSS.Strings.Virtual_String := Lines (1);
-         --  We should keep copy of regexp subject string while we have a match
-         Match : constant VSS.Regular_Expressions.Regular_Expression_Match :=
-           Crate_Pattern.Match (First);
-      begin
-         if Match.Has_Match then
-            Project := Match.Captured (1);
-            Project.Append (".gpr");
-         end if;
-      end;
-
+      --  Find project file in `alr show` output. There are several cases to cover.
+      --
+      --  If alire.toml contains a "project-files" entry providing a list of
+      --  projects, `alr show` prints one line per project of the pattern:
+      --  Project_File: ...
+      --
+      --  Otherwise `alr show` doesn't print a Project_File line and we can expect
+      --  there to be a project named identically to the crate name.
+      --
+      --  So the strategy below is to first use the crate name as a project
+      --  name, and then override it if a Project_File line is found (the first
+      --  one is taken).
+
+      --  When `alr show` is called in a directory where /alire/ and /config/
+      --  don't exist, the command auto-generates those directories and prints a
+      --  few lines of output before the actual crate information. So we can't
+      --  assume that the crate name will be on the first line.
       for Line of Lines loop
          declare
-            Match : constant VSS.Regular_Expressions.Regular_Expression_Match
-              := Project_Pattern.Match (Line, Anchored);
+            --  We should keep copy of regexp subject string while we have a match
+            Match : constant VSS.Regular_Expressions.Regular_Expression_Match :=
+            Crate_Pattern.Match (Line);
          begin
             if Match.Has_Match then
                Project := Match.Captured (1);
+               Project.Append (".gpr");
                exit;
             end if;
          end;
       end loop;
 
-      if Project.Is_Empty then
-         Error.Append ("No project file is found by alire");
-      end if;
-
-      --  Find variables in `alr printenv` output
-
-      Start_Alire
-        (ALR.all, "--non-interactive", "printenv", Root, Error, Lines);
-
-      GNAT.OS_Lib.Free (ALR);
-
-      --  Find variables in `alr printenv` output
-
+      --  Next check if there is a Project_File line, take the first one.
       for Line of Lines loop
          declare
             Match : constant VSS.Regular_Expressions.Regular_Expression_Match
-              := Export_Pattern.Match (Line, Anchored);
+              := Project_Pattern.Match (Line, Anchored);
          begin
             if Match.Has_Match then
-               Environment.Insert
-                 (Key   => VSS.Strings.Conversions.To_UTF_8_String
-                             (Match.Captured (1)),
-                  Value => VSS.Strings.Conversions.To_UTF_8_String
-                             (Match.Captured (2)));
+               Project := Match.Captured (1);
+               exit;
             end if;
          end;
       end loop;
-   end Run_Alire;
+
+      if Project.Is_Empty then
+         Error.Append ("No project file could be determined from the output of `alr show`:");
+         for Line of Lines loop
+            Error.Append (Line);
+         end loop;
+      end if;
+
+   end Determine_Alire_Project;
 
    ---------------
    -- Run_Alire --
    ---------------
 
-   procedure Run_Alire
+   procedure Setup_Alire_Env
      (Root        : String;
       Has_Alire   : out Boolean;
       Error       : out VSS.Strings.Virtual_String;
@@ -221,7 +214,7 @@ package body LSP.Ada_Handlers.Alire is
             end if;
          end;
       end loop;
-   end Run_Alire;
+   end Setup_Alire_Env;
 
    -----------------
    -- Start_Alire --

source/ada/lsp-ada_handlers-alire.ads

@@ -24,20 +24,19 @@ with VSS.Strings;
 private
 package LSP.Ada_Handlers.Alire is
 
-   procedure Run_Alire
+   procedure Determine_Alire_Project
      (Root        : String;
       Has_Alire   : out Boolean;
       Error       : out VSS.Strings.Virtual_String;
-      Project     : out VSS.Strings.Virtual_String;
-      Environment : in out GPR2.Environment.Object);
+      Project     : out VSS.Strings.Virtual_String);
    --  if Root directory contains `alire.toml` file, then run
-   --  `alr printenv` and fetch the first project from `alire.toml`.
+   --  `alr show` and determine the project from the output.
 
-   procedure Run_Alire
+   procedure Setup_Alire_Env
      (Root        : String;
       Has_Alire   : out Boolean;
       Error       : out VSS.Strings.Virtual_String;
       Environment : in out GPR2.Environment.Object);
-   --  The same as above, but without fetching the project file
+   --  Run `alr printenv` and set up the obtained environment variables
 
 end LSP.Ada_Handlers.Alire;

source/ada/lsp-ada_handlers-project_loading.adb

@@ -428,24 +428,22 @@ package body LSP.Ada_Handlers.Project_Loading is
 
          if Project.Is_Empty then
 
-            LSP.Ada_Handlers.Alire.Run_Alire
+            LSP.Ada_Handlers.Alire.Determine_Alire_Project
               (Root        => Root (Self).Display_Full_Name,
                Has_Alire   => Has_Alire,
                Error       => Errors,
-               Project     => Project,
-               Environment => Environment);
+               Project     => Project);
 
             Status := Alire_Project;
-         else
+         end if;
 
-            LSP.Ada_Handlers.Alire.Run_Alire
-              (Root        => Root (Self).Display_Full_Name,
-               Has_Alire   => Has_Alire,
-               Error       => Errors,
-               Environment => Environment);
+         LSP.Ada_Handlers.Alire.Setup_Alire_Env
+            (Root        => Root (Self).Display_Full_Name,
+            Has_Alire   => Has_Alire,
+            Error       => Errors,
+            Environment => Environment);
 
-            Status := Valid_Project_Configured;
-         end if;
+         Status := Valid_Project_Configured;
 
          if Has_Alire and then not Errors.Is_Empty then