Unregister S3 methods explicitly

NEWS.md

@@ -1,5 +1,8 @@
 # devtools 1.9.1.9000
 
+* Fix longstanding lazy load database corruption issues when reloading packages
+  which define S3 methods on generics from base or other packages (#1001, @jimhester).
+
 * `document()` now only runs `update_collate()` once.
 
 * Bugfix for `Remotes: ` feature that prevented it from working if devtools was

R/install.r

@@ -63,6 +63,13 @@ install <- function(pkg = ".", reload = TRUE, quick = FALSE, local = TRUE,
   pkg <- as.package(pkg)
   check_build_tools(pkg)
 
+  # Forcing all of the promises for the current namespace now will avoid lazy-load
+  # errors when the new package is installed overtop the old one.
+  # https://stat.ethz.ch/pipermail/r-devel/2015-December/072150.html
+  if (is_loaded(pkg)) {
+    eapply(ns_env(pkg), force, all.names = TRUE)
+  }
+
   if (!quiet) {
     message("Installing ", pkg$package)
   }

R/load.r

@@ -96,11 +96,10 @@ load_all <- function(pkg = ".", reset = TRUE, recompile = FALSE,
 
   # Reloading devtools is a special case. Normally, objects in the
   # namespace become inaccessible if the namespace is unloaded before the
-  # the object has been accessed. This is kind of a hack - using as.list
-  # on the namespace accesses each object, making the objects accessible
-  # later, after the namespace is unloaded.
+  # object has been accessed. Instead we force the object so they will still be
+  # accessible.
   if (pkg$package == "devtools") {
-    as.list(ns_env(pkg))
+    eapply(ns_env(pkg), force, all.names = TRUE)
   }
 
   # Check description file is ok

R/unload.r

@@ -33,10 +33,10 @@ unload <- function(pkg = ".") {
   # This is a hack to work around unloading devtools itself. The unloading
   # process normally makes other devtools functions inaccessible,
   # resulting in "Error in unload(pkg) : internal error -3 in R_decompress1".
-  # If we simply access them here using as.list (without calling them), then
-  # they will remain available for use later.
+  # If we simply force them first, then they will remain available for use
+  # later.
   if (pkg$package == "devtools") {
-    as.list(ns_env(pkg))
+    eapply(ns_env(pkg), force, all.names = TRUE)
   }
 
   # If the package was loaded with devtools, any s4 classes that were created