My package (let's call it A) depends on another package B. I need to modify a function f
in B that has a bug that is causing my package to fail. The problem is that f
is an unexported function.
If f
was exported, I could use the technique described in this post to R-help:
The few times I want to patch a function like this, I use:
unlockBinding(name, env); assignInNamespace(name, value, ns=pkgName, envir=env); assign(name, value, envir=env); lockBinding(name, env);
But because f
is unexported, this doesn't work.
Simple example to illustrate the problem:
# rf is an exported function from the stats package; this works
foo <- function(x) x
unlockBinding("rf", as.environment("package:stats"))
assignInNamespace("rf", foo, ns="stats", pos="package:stats")
assign("rf", bar, pos="package:stats")
lockBinding("rf", as.environment("package:stats"))
rf(42)
# 42
# C_rf is an unexported object that rf() uses; this fails
bar <- function(x) x + 1
unlockBinding("C_rf", as.environment("package:stats"))
assignInNamespace("C_rf", bar, ns="stats", pos="package:stats")
assign("C_rf", bar, pos="package:stats")
lockBinding("C_rf", as.environment("package:stats"))
# Error in unlockBinding("C_rf", as.environment("package:stats")) :
# no binding for "C_rf"
Is it possible to modify f
?
As it turns out, I only had to remove the unlockBinding
, assign
and lockBinding
calls.
bar <- function(x) x + 1
assignInNamespace("C_rf", bar, ns="stats", pos="package:stats")
stats:::C_rf
# function(x) x + 1
rf(3, 2, 2)
#Error in .Call(C_rf, n, df1, df2) :
# first argument must be a string (of length 1) or native symbol reference
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