On go1.19, A blank import of "errors" increases the binary size by ~15.5KiB due to the transitive dependency on reflectlite.
The hard dependency occurs because of the program initialize variable for:
var errorType = reflectlite.TypeOf((*error)(nil)).Elem()
We could consider a trick similar to 419757
This is relevant since many packages depend on errors only for errors.New, and we should not expect those packages to force reflectlite to be transitively linked in.
Comment From: dsnet
I also wonder if programs that depend on both reflect and reflectlite could just end up using the reflect package instead and save that ~15.5KiB. I don't know how to implement that without some linker magic.
Comment From: cherrymui
Perhaps the reflect package can can just import reflectlite and build on top of it, instead of duplicating code. (The reflectlite package may need to export more things for reflect to use, and that is fine, as it is an internal package.)
It would look nicer if the reflect package is self-contained. But probably okay if it is not.
Comment From: dsnet
It would look nicer if the reflect package is self-contained. But probably okay if it is not.
For "look nicer", are you referring to how the package appears in pkgsite? Implementing "reflect" in terms of "reflectlite" will probably require the primary types to be declared in reflectlite with type aliases left in "reflect". For an unrelated package split that I was doing, @mvdan mentioned that we might want to teach the pkgsite certain patterns where it hoists a type alias as if it were declared locally (in terms of presentation).
Comment From: cherrymui
I was mostly thinking about reading the code. It would be nicer if the code stays together.
For documentation, reflectlite doesn't define many types for reflect to export, so it is probably not too bad. We probably could alias Kind and Type, or duplicate them, which shouldn't be too bad. I don't think we can alias Value as we need to define more methods on reflect.Value. reflect.Value could probably wrap reflectlite.Value.
Comment From: qiulaidongfeng
The issue has been settled go build the following code, with or without import errors, is 1.4M in size
package main
import _ "errors"
func main() {
}
Comment From: qiulaidongfeng
See https://github.com/golang/go/issues/54341#issuecomment-1879968971 , I think this issue can be closed. @dsnet Could you please close this issue?
Comment From: ianlancetaylor
Closing based on previous comment. Please comment if you disagree. Thanks.