Alire.Config.Edit: fix for --config with relative path (#848)

src/alire/alire-config-edit.adb

@@ -393,7 +393,7 @@ package body Alire.Config.Edit is
    -- Path --
    ----------
 
-   function Path return String is
+   function Path return Absolute_Path is
    begin
       if Config_Path /= null then -- Case with switch (TODO)
          return Config_Path.all;
@@ -407,7 +407,7 @@ package body Alire.Config.Edit is
    -- Set_Path --
    --------------
 
-   procedure Set_Path (Path : String) is
+   procedure Set_Path (Path : Absolute_Path) is
    begin
       if Config_Path /= null then
          raise Constraint_Error with "Custom path already set";

src/alire/alire-config-edit.ads

@@ -17,14 +17,14 @@ package Alire.Config.Edit is
    --  here all non-preelaborable things related to config loading. This
    --  way, querying stays preelaborable.
 
-   function Path return String;
+   function Path return Absolute_Path;
    --  The in-use global config folder path.
    --  In order of decreasing precedence:
    --  * A manually set path with Set_Path (below)
    --  * An ALR_CONFIG env given folder
    --  * Default per-platform path (see alire-platforms-*)
 
-   procedure Set_Path (Path : String);
+   procedure Set_Path (Path : Absolute_Path);
    --  Override global config folder path
 
    function Indexes_Directory return Absolute_Path is (Path / "indexes");

src/alr/alr-commands.adb

@@ -388,10 +388,18 @@ package body Alr.Commands is
          --  Also use a fancier busy spinner
       end if;
 
-      if Command_Line_Config_Path     /= null and then
+      if Command_Line_Config_Path /= null and then
          Command_Line_Config_Path.all /= ""
       then
-         Alire.Config.Edit.Set_Path (Command_Line_Config_Path.all);
+         if not Alire.Check_Absolute_Path (Command_Line_Config_Path.all) then
+            --  Make an absolute path from user relative path
+            Alire.Config.Edit.Set_Path
+              (Ada.Directories.Full_Name (Command_Line_Config_Path.all));
+         else
+
+            --  Use absolute path from user
+            Alire.Config.Edit.Set_Path (Command_Line_Config_Path.all);
+         end if;
       end if;
 
       Create_Alire_Folders;

testsuite/tests/config/relative_config_path/test.py

@@ -0,0 +1,20 @@
+"""
+Verify that using a relative path for Alire config dir is ok
+"""
+
+import os
+
+from glob import glob
+
+from drivers.alr import run_alr
+from drivers.asserts import assert_eq
+from drivers.helpers import lines_of
+
+run_alr("--config", ".", "config", "--global",
+        "--set", "some_config_key", "true")
+
+
+assert_eq("some_config_key = true\n", lines_of ("config.toml")[0])
+
+
+print('SUCCESS')

testsuite/tests/config/relative_config_path/test.yaml

@@ -0,0 +1,3 @@
+driver: python-script
+indexes:
+    basic_index: {}