* lisp/ob-ref.el (org-babel-ref-resolve): When the result an empty
list, then treat it as a list, not as the symbol nil.
* testing/lisp/test-ob.el (test-ob/return-empty-list-from-post-block):
Add new test.
* etc/ORG-NEWS (Post-processing code blocks can return an empty list):
Document change in behavior.
---
etc/ORG-NEWS | 6 ++++++
lisp/ob-ref.el | 2 +-
testing/lisp/test-ob.el | 24 ++++++++++++++++++++++++
3 files changed, 31 insertions(+), 1 deletion(-)
diff --git a/etc/ORG-NEWS b/etc/ORG-NEWS
index 4728528f8..74095d101 100644
--- a/etc/ORG-NEWS
+++ b/etc/ORG-NEWS
@@ -425,6 +425,12 @@ The new variable name is =org-plantuml-args=. It now
applies to both
jar PlantUML file and executable.
** Miscellaneous
+*** Post-processing code blocks can return an empty list
+
+When the result of a regular code block is nil, then that was already
+treated as an empty list. Now that is also the case for code blocks
+that post-process the result of another block.
+
*** Styles are customizable in ~biblatex~ citation processor
It is now possible to add new styles or modify old ones in ~biblatex~
diff --git a/lisp/ob-ref.el b/lisp/ob-ref.el
index b79e47900..2b4a16aea 100644
--- a/lisp/ob-ref.el
+++ b/lisp/ob-ref.el
@@ -199,7 +199,7 @@ (defun org-babel-ref-resolve (ref)
(org-babel-execute-src-block nil info params))))
(error "Reference `%s' not found in this buffer" ref))))
(cond
- ((symbolp result) (format "%S" result))
+ ((and result (symbolp result)) (format "%S" result))
((and index (listp result))
(org-babel-ref-index-list index result))
(t result)))))))))
diff --git a/testing/lisp/test-ob.el b/testing/lisp/test-ob.el
index 99912fe63..8d1548fe1 100644
--- a/testing/lisp/test-ob.el
+++ b/testing/lisp/test-ob.el
@@ -26,6 +26,30 @@ (require 'ob-ref)
(require 'org-table)
(eval-and-compile (require 'cl-lib))
+(ert-deftest test-ob/return-empty-list-from-post-block ()
+ "When the result of a post-processing source block is an empty
+list, then it should be treated as such; not as the symbol nil."
+ (should
+ (let ((default-directory temporary-file-directory))
+ (org-test-with-temp-text
+ "
+#+name: addheader
+#+header: :var rows=\"\"
+#+begin_src elisp :hlines yes
+ '()
+#+end_src
+#+header: :post addheader(*this*)
+#+<point>begin_src emacs-lisp :results table
+#+end_src
+#+RESULTS:
+: nil"
+ (org-babel-execute-src-block)
+ (goto-char (1- (point-max)))
+ (equal (buffer-substring-no-properties
+ (line-beginning-position)
+ (line-end-position))
+ "#+RESULTS:")))))
+
(ert-deftest test-ob/indented-cached-org-bracket-link ()
"When the result of a source block is a cached indented link it
should still return the link."
--
2.37.3
