Add fallback package name in case the DESCRIPTION file cannot be read.

When the DESCRIPTION file is not present, the package name is inferred to
be the basename of pkgdir, which is what it used to be before #130.

Author: mcol

NEWS.md

@@ -2,7 +2,9 @@
 
 Items for next release go here
 
-Extended `loo_pit()` for discrete data.
+* Extended `loo_pit()` for discrete data.
+* Fix regression (introduced in 2.4.0) in the compilation of packages with
+custom Stan functions by @mcol in #137
 
 # rstantools 2.4.0
 

R/rstan_config.R

@@ -214,7 +214,10 @@ rstan_config <- function(pkgdir = ".") {
     eigen_incl <- ifelse(utils::packageVersion('StanHeaders') >= "2.31",
                          "#include <stan/math/prim/fun/Eigen.hpp>",
                          "#include <stan/math/prim/mat/fun/Eigen.hpp>")
-    pkgname <- unname(read.dcf("DESCRIPTION", "Package")[1, 1])
+    pkgname <- tryCatch(unname(read.dcf("DESCRIPTION", "Package")[1, 1]),
+                        warning = function(w) {
+                          basename(pkgdir)
+                        })
     cat("#include <exporter.h>",
         eigen_incl,
         "#include <stan/math/prim/meta.hpp>",