Rely on load-true-file-name if exists for version retrieval

Author: vspinu

lisp/ess-r-mode.el

@@ -1552,14 +1552,14 @@ environment from GitHub and attaches it to the search path. If
 the file already exists on disk from a previous download then the
 download step is omitted. This function returns t if the ESSR
 load is successful, and nil otherwise."
-  (let ((loader (ess-file-content (expand-file-name "ESSR/LOADREMOTE" ess-etc-directory))))
+  (let ((loader (ess-file-content (expand-file-name "ESSR/LOADREMOTE" ess-etc-directory)))
+        (essr (or essr-version
+                  ;; FIXME: Hack: on MELPA essr-version is not set
+                  (lm-with-file (expand-file-name "ess.el" ess-lisp-directory)
+                    (lm-header "ESSR-Version"))
+                  (error "`essr-version' could not be automatically inferred from ess.el file"))))
     (or (with-temp-message "Fetching and loading ESSR into the remote ..."
-          (let ((essr (or essr-version
-                          ;; FIXME: Hack: on MELPA essr-version is not set
-                          (lm-with-file (expand-file-name "ess.el" ess-lisp-directory)
-                            (lm-header "ESSR-Version"))
-                          (error "`essr-version' could not be automatically inferred from ess.el file"))))
-            (ess-boolean-command (format loader essr-version))))
+          (ess-boolean-command (format loader essr)))
         (let ((errmsg (with-current-buffer " *ess-command-output*" (buffer-string))))
           (message (format "Couldn't load or download ESSR.rds on the remote.\n Error: %s\n Injecting local copy of ESSR." errmsg))
           nil))))

lisp/ess.el

@@ -58,11 +58,17 @@
 ;; Versions
 
 (defconst ess-version (eval-when-compile
-                        (lm-version (or load-file-name buffer-file-name)))
+                        (lm-version (or (and (boundp 'load-true-file-name)
+                                             load-true-file-name)
+                                        load-file-name
+                                        buffer-file-name)))
   "Version of ESS currently loaded.")
 
 (defconst essr-version (eval-when-compile
-                         (lm-with-file (or load-file-name buffer-file-name)
+                         (lm-with-file (or (and (boundp 'load-true-file-name)
+                                                load-true-file-name)
+                                           load-file-name
+                                           buffer-file-name)
                            (lm-header "ESSR-Version")))
   "Version of ESSR package.")