[elpa] externals/ess 536b5b914a: Move `ess-r` startup commands out of `ess-r-post-run-hook`

[ELPA Syncer]

branch: externals/ess
commit 536b5b914a75afa37ee05aa8ba0aecd0f9c9eb33
Author: Lionel Henry <lionel.hry@gmail.com>
Commit: Lionel Henry <lionel.hry@gmail.com>

    Move `ess-r` startup commands out of `ess-r-post-run-hook`
    
    They are blocking commands and the user might have added streaming
    commands to the hook.
    
    Also document why users should be careful when mixing blocking and
    streaming commands.
---
 lisp/ess-custom.el |  6 +++++-
 lisp/ess-r-mode.el | 16 ++++++++++------
 2 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/lisp/ess-custom.el b/lisp/ess-custom.el
index 9574f5fd5a..8f61588dac 100644
--- a/lisp/ess-custom.el
+++ b/lisp/ess-custom.el
@@ -1400,7 +1400,11 @@ Good for setting up your directory."
 
 (defcustom ess-post-run-hook nil
   "Hook to call just after the ESS process starts up.
-Good for evaluating ESS code."
+Currently this should not be used to interact with the inferior
+process because this hook runs too early, before the inferior
+mode had a chance to properly start up the process. To interact
+with the process, you must use a mode-specific hook like
+'ess-r-post-run-hook'."
   :group 'ess-hooks
   :type 'hook)
 
diff --git a/lisp/ess-r-mode.el b/lisp/ess-r-mode.el
index 16e5d1a02b..8643924b03 100644
--- a/lisp/ess-r-mode.el
+++ b/lisp/ess-r-mode.el
@@ -544,10 +544,12 @@ fill=TRUE); try(traceback(), silent=TRUE)})\n")
 ;; send "run". So this is no longer generic and inferior modes need
 ;; to call this manually. One way to fix this would be to make
 ;; `inferior-ess' a `cl-defgeneric'.
-(defvar ess-r-post-run-hook '((lambda ()
-                                (ess-execute-screen-options t)
-                                (ess-set-working-directory default-directory)))
-  "Functions run in process buffer after the initialization of R process.")
+(defvar ess-r-post-run-hook nil
+  "Functions run in process buffer after the initialization of R process.
+Make sure to call blocking commands (e.g. based on `ess-command')
+first. Streaming commands (e.g. based on `ess-send-string')
+should come last, otherwise they will make R busy and the
+blocking commands will throw an error.")
 
 ;;;###autoload
 (defun run-ess-r (&optional start-args)
@@ -648,10 +650,12 @@ Executed in process buffer."
     (ess-command (format
                   "if (identical(getOption('pager'), file.path(R.home(), 
'bin', 'pager')))
                        options(pager = '%s')\n"
-                  inferior-ess-pager)))
-  (ess-r-load-ESSR)
+                  inferior-ess-pager))
+    (ess-r-load-ESSR))
   (when inferior-ess-language-start
     (ess-command (concat inferior-ess-language-start "\n")))
+  (ess-execute-screen-options t)
+  (ess-set-working-directory default-directory)
   (when ess-use-tracebug
     (ess-tracebug 1))
   (add-hook 'ess-presend-filter-functions 'ess-R-scan-for-library-call nil 
'local)