Cannot set R :session in file property for interactive use

Question

I would like all R src blocks in an org file to use the same session interactively and have included a minimal example below. I added the #+PROPERTY line as in the manual and ran C-c C-c as suggested in the related questions to ensure the property takes effect, but it does not seem to work when trying to run src blocks in an interactive manner (i.e. running C-c C-c on the src blocks)

I am unsure what I am missing or misunderstanding. Is it possible to use file-level properties for interactively running src blocks?

Cannot add general block header arguments in org mode

Org-babel: using properties as code block header arguments, how to make it work?

Org manual

#+title: Test
#+PROPERTY: header-args:R:  :session *R*

Load a library in one block

#+begin_src R
library(dplyr)
#+end_src

#+RESULTS:
| dplyr     |
| stats     |
| graphics  |
| grDevices |
| utils     |
| datasets  |
| methods   |
| base      |

Try to use a function from that library in another block

#+begin_src R
mtcars %>% filter(cyl == 4)
#+end_src

Executing the above with C-c C-c fails because it cannot find ~%>%~, so the two src blocks must be running in
independent sessions.

Error in mtcars %>% filter(cyl == 4) : could not find function "%>%"
Calls: <Anonymous> -> <Anonymous>
Execution halted

Answer 1

[Expanding the comment into an answer]

There should be no colon after header-args:R:

#+PROPERTY: header-args:R  :session *R*

It's true that all those colons are confusing, but they are important, so you might want to get the syntax "into your fingers" so to speak.

• The PROPERTY keyword is always followed by a colon.
• The property name is never followed by a colon. In this case, the property name is header-args:R.
• The property value in the case of header-args is a sequence of header args, each of which starts with a colon.

In general, property values are arbitrary strings, but header-args (either bare or qualified by a language) have stricter requirements.

The manual shows an R example, but does not quite define the syntax: the property name is header-args:<LANG> where <LANG> is the same string as the one you use in a #+BEGIN_SRC ... #+END_SRC block. So in this case, it should be header-args:R.

I'm not sure how Org mode parsed header-args:R: - I assume it thought the <LANG> component was R: and, looking for such source blocks, it did not find any, so the setting was ignored.