Remove Alire support from lsp-mode Ada client. (#4484)

Alire support is now available directly in the Ada Language Server and
handles the functionality currently implemented in lsp-mode.  In
addition, when the project file is not specified by the LSP client,
the language server will intelligently locate the project file using
`alr` when an Alire configuration file exists.  Therefore, the default
setting of the project file has been changed (from "default.gpr" to
nil) to enable the server to automatically locate the project file in
normal situations.  The server will also automatically find a project
file for a non-Alire project if it uniquely exists in the root
folder (i.e., no other project file exists in this folder).  The new
project file default setting provides for a better out-of-the-box
configuration to support common situations.

clients/lsp-ada.el

@@ -33,18 +33,31 @@
   :tag "Language Server"
   :package-version '(lsp-mode . "6.2"))
 
-(lsp-defcustom lsp-ada-project-file "default.gpr"
-  "Set the project file full path to configure the language server with.
-  The ~ prefix (for the user home directory) is supported.
-  See https://github.com/AdaCore/ada_language_server for a per-project
-  configuration example."
-  :type 'string
+(lsp-defcustom lsp-ada-project-file nil
+  "GNAT Project file used to configure the Language Server.
+
+Both absolute and relative paths are supported within the project file
+name.  When a relative path is used, the path is relative to the root
+folder.
+
+When the project file is not specified, the Language Server will attempt
+to determine the project file itself, either by querying \\='alr\\=', if
+the root folder contains an alire.toml file and \\='alr\\=' was found in
+the path, or otherwise by searching for a unique project file in the
+root folder.  For Alire projects, whose project file was discovered by
+querying \\='alr\\=', the server will also query and populate the Alire
+environment."
+  :type '(choice (string :tag "File")
+                 (const  :tag "Not Specified" nil))
   :group 'lsp-ada
-  :package-version '(lsp-mode . "6.2")
+  :link '(url-link :tag "Configuration Example"
+                   "https://github.com/AdaCore/ada_language_server")
+  :package-version '(lsp-mode . "9.0.1")
   :lsp-path "ada.projectFile")
+;;;###autoload(put 'lsp-ada-project-file 'safe-local-variable 'stringp)
 
 (lsp-defcustom lsp-ada-option-charset "UTF-8"
-  "The charset to use by the Ada Language server. Defaults to 'UTF-8'."
+  "The charset to use by the Ada Language server. Defaults to \\='UTF-8\\='."
   :type 'string
   :group 'lsp-ada
   :package-version '(lsp-mode . "6.2")
@@ -63,12 +76,6 @@
   :risky t
   :type 'file)
 
-(defcustom lsp-ada-alire-executable "alr"
-  "The alire executable to run when a project is detected."
-  :type 'string
-  :group 'lsp-ada
-  :package-version '(lsp-mode "9.0.0"))
-
 (defcustom lsp-ada-semantic-token-face-overrides
   '(("namespace" . default)
     ("modifier"  . lsp-face-semhl-keyword))
@@ -132,26 +139,6 @@
                               (lsp-ada--als-latest-release-url)
                               "ada-ls"))))
 
-(defun lsp-ada--environment ()
-  "Add environmental variables if needed."
-  (let ((project-root (lsp-workspace-root)))
-    ;; When there is an alire project, include its environment
-    (when (file-exists-p
-           (concat (file-name-as-directory project-root)
-                   "alire.toml"))
-      (let ((alr-executable (executable-find lsp-ada-alire-executable)))
-        (if alr-executable
-            ;; Transform output variables to environment
-            (let ((env-output (shell-command-to-string (concat alr-executable " printenv --unix"))))
-              (let ((var-strings (split-string env-output "\n")))
-                (mapcar (lambda (string)
-                          (if (string-match (rx "export" space (group (one-or-more ascii)) "=" "\"" (group (one-or-more ascii)) "\"") string)
-                              (let ((var-name (match-string 1 string))
-                                    (var-value (match-string 2 string)))
-                                (cons var-name var-value))))
-                        var-strings)))
-          (lsp--error "Found alire.toml but the executable %s could not be found" alr-executable))))))
-
 (lsp-dependency
  'ada-ls
  '(:download :url lsp-ada--als-latest-release-url
@@ -175,8 +162,7 @@
                   :semantic-tokens-faces-overrides `( :types ,lsp-ada-semantic-token-face-overrides
                                                       :modifiers ,lsp-ada-semantic-token-modifier-face-overrides)
                   :server-id 'ada-ls
-                  :synchronize-sections '("ada")
-                  :environment-fn 'lsp-ada--environment))
+                  :synchronize-sections '("ada")))
 
 (lsp-register-client
  (make-lsp-client :new-connection (lsp-stdio-connection
@@ -186,8 +172,7 @@
                   :priority -1
                   :download-server-fn (lambda (_client callback error-callback _update?)
                                         (lsp-package-ensure 'ada-ls callback error-callback))
-                  :server-id 'gpr-ls
-                  :environment-fn #'lsp-ada--environment))
+                  :server-id 'gpr-ls))
 
 (lsp-consistency-check lsp-ada)