Thanks for the report. Fixed in R-devel and R-patched (both R-4-4-branch and R-4-3-branch).
On Fri, 5 Apr 2024, June Choe wrote:
[You don't often get email from jchoe...@gmail.com. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ] There seems to be a bug in out-of-bounds assignment of list objects to an expression() vector. Tested on release and devel. (Many thanks to folks over at Mastodon for the help narrowing down this bug) When assigning a list into an existing index, it correctly errors on incompatible type, and the expression vector is unchanged: ``` x <- expression(a,b,c) x[[3]] <- list() # Error x #> expression(a, b, c) ``` When assigning a list to an out of bounds index (ex: the next, n+1 index), it errors the same but now changes the values of the vector to NULL: ``` x <- expression(a,b,c) x[[4]] <- list() # Error x #> expression(NULL, NULL, NULL) ``` Curiously, this behavior disappears if a prior attempt is made at assigning to the same index, using a different incompatible object that does not share this bug (like a function): ``` x <- expression(a,b,c) x[[4]] <- base::sum # Error x[[4]] <- list() # Error x #> expression(a, b, c) ``` That "protection" persists until x[[4]] is evaluated, at which point the bug can be produced again: ``` x[[4]] # Error x[[4]] <- list() # Error x #> expression(NULL, NULL, NULL) ``` Note that `x` has remained a 3-length vector throughout. Best, June [[alternative HTML version deleted]] ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
-- Luke Tierney Ralph E. Wareham Professor of Mathematical Sciences University of Iowa Phone: 319-335-3386 Department of Statistics and Fax: 319-335-3017 Actuarial Science 241 Schaeffer Hall email: luke-tier...@uiowa.edu Iowa City, IA 52242 WWW: http://www.stat.uiowa.edu/ ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
