Re: Help debugging R source code block output problem with :session

[Jack Kamm]

Hi Chuck and Dylan,

"Berry, Charles" <ccberry@health.ucsd.edu> writes:

> This problem has been bugging people for years and previous attempts to solve 
> it have always run up against creating more problems in the process of 
> solving this one.
>
> If you do decide to dig into solving this, please be sure that remote 
> sessions and graphical outputs are not broken.  test-ob-R.el does not cover 
> those cases.  In fact, it is pretty short, so there are probably other things 
> that could break without `make test' complaining.

I think I have found a robust solution to this issue, which I've
attached.

The solution avoids parsing for prompts at all, thus it should be robust
even for the case when the beginning of an output line looks like a
prompt.

I tested that the unit tests all pass, and that remote sessions and
graphical outputs still work. I also added Dylan's examples as unit
tests.

Cheers,
Jack

>From 76d0eaa31506ce8a2f81f64eae43161db5721317 Mon Sep 17 00:00:00 2001
From: Jack Kamm <jackkamm@gmail.com>
Date: Mon, 7 Sep 2020 00:41:52 -0700
Subject: [PATCH] ob-R: Fix session output with substrings matching prompts

* lisp/ob-R.el (ess-send-string): Declare external function.
(org-babel-R-evaluate-session): New implementation for session output
results, that replaces calls to org-babel-comint-with-output with
custom code.
* testing/lisp/test-ob-R.el (test-ob-R/prompt-output): New test for
output results containing angle brackets.
(test-ob-R/output-nonprinted): New test for output results that aren't
explicitly printed.

Fixes issue reported in
https://orgmode.org/list/875zgjh8wn.fsf@gmail.com/,
https://orgmode.org/list/87r1rqled0.fsf@havana/
---
 lisp/ob-R.el              | 37 +++++++++++++++++++------------------
 testing/lisp/test-ob-R.el | 13 +++++++++++++
 2 files changed, 32 insertions(+), 18 deletions(-)

diff --git a/lisp/ob-R.el b/lisp/ob-R.el
index 5e9d35f58..b37e3965a 100644
--- a/lisp/ob-R.el
+++ b/lisp/ob-R.el
@@ -38,6 +38,8 @@ (declare-function ess-make-buffer-current "ext:ess-inf" ())
 (declare-function ess-eval-buffer "ext:ess-inf" (vis))
 (declare-function ess-wait-for-process "ext:ess-inf"
                  (&optional proc sec-prompt wait force-redisplay))
+(declare-function ess-send-string "ext:ess-inf"
+                 (process string &optional visibly message _type))
 
 (defconst org-babel-header-args:R
   '((width              . :any)
@@ -437,24 +439,23 @@ (defun org-babel-R-evaluate-session
          (org-babel-import-elisp-from-file tmp-file '(16)))
        column-names-p)))
     (output
-     (mapconcat
-      'org-babel-chomp
-      (butlast
-       (delq nil
-            (mapcar
-             (lambda (line) (when (> (length line) 0) line))
-             (mapcar
-              (lambda (line) ;; cleanup extra prompts left in output
-                (if (string-match
-                     "^\\([>+.]\\([ ][>.+]\\)*[ ]\\)"
-                     (car (split-string line "\n")))
-                    (substring line (match-end 1))
-                  line))
-              (org-babel-comint-with-output (session org-babel-R-eoe-output)
-                (insert (mapconcat 'org-babel-chomp
-                                   (list body org-babel-R-eoe-indicator)
-                                   "\n"))
-                (inferior-ess-send-input)))))) "\n"))))
+     (let* ((tmp-file (org-babel-temp-file "R-")))
+       (with-temp-file tmp-file
+        (insert (concat body "\n" org-babel-R-eoe-indicator)))
+       (with-current-buffer session
+        (let* ((process (get-buffer-process (current-buffer)))
+               (string-buffer "")
+               (comint-output-filter-functions
+                (cons (lambda (text) (setq string-buffer
+                                           (concat string-buffer text)))
+                      comint-output-filter-functions)))
+          (ess-send-string
+           process (format "source('%s', print.eval=TRUE)"
+                           (org-babel-process-file-name tmp-file 'noquote)))
+          (while (not (string-match (regexp-quote org-babel-R-eoe-output)
+                                    string-buffer))
+            (accept-process-output process))
+          (substring string-buffer 0 (match-beginning 0))))))))
 
 (defun org-babel-R-process-value-result (result column-names-p)
   "R-specific processing of return value.
diff --git a/testing/lisp/test-ob-R.el b/testing/lisp/test-ob-R.el
index 7ce340ba4..ff7ea19d5 100644
--- a/testing/lisp/test-ob-R.el
+++ b/testing/lisp/test-ob-R.el
@@ -97,6 +97,19 @@ (ert-deftest test-ob-R/results-file ()
      (org-babel-goto-named-result "TESTSRC") (forward-line 1)
      (should (string= "[[file:junk/test.org]]"
                      (buffer-substring-no-properties (point-at-bol) 
(point-at-eol)))))))
+
+(ert-deftest test-ob-R/prompt-output ()
+  (let (ess-ask-for-ess-directory ess-history-file)
+    (org-test-with-temp-text
+     "#+begin_src R :results output :session\nprint(\"<X> <Y> 
<!>\")\nprint(\"one <two> three\")\nprint(\"end\")\n#+end_src\n"
+     (should (string= "[1] \"<X> <Y> <!>\"\n[1] \"one <two> three\"\n[1] 
\"end\"\n" (org-babel-execute-src-block))))))
+
+(ert-deftest test-ob-R/output-nonprinted ()
+  (let (ess-ask-for-ess-directory ess-history-file)
+    (org-test-with-temp-text
+     "#+begin_src R :results output :session\n4.0 * 
3.5\nlog(10)\nlog10(10)\n(3 + 1) * 5\n3^-1\n1/0\n#+end_src\n"
+     (should (string= "[1] 14\n[1] 2.302585\n[1] 1\n[1] 20\n[1] 0.3333333\n[1] 
Inf\n" (org-babel-execute-src-block))))))
+
 (provide 'test-ob-R)
 
 ;;; test-ob-R.el ends here
-- 
2.28.0