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knitr creates a copy of evaluate::evaluate as the default evaluate hook value #1441

aronatkins opened this issue Oct 4, 2017 · 3 comments


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aronatkins commented Oct 4, 2017

The default evaluate hook is defined as:


Lines 9 to 14 in 0d648a6

.default.hooks = list(
source = .out.hook, output = .out.hook, warning = .out.hook,
message = .out.hook, error = .out.hook, plot = .plot.hook,
inline = .inline.hook, chunk = .out.hook, text = identity,
evaluate = evaluate::evaluate, document = identity

This means that the default hook is tied to whatever version of evaluate was available at the time knitr was installed. If the version of evaluate changes, the knitr hook is not changed to reflect the new definition of evaluate::evaluate.

This explains errors like:

Quitting from lines 9-10 (helloworld1.Rmd)
Error in evaluate_call(expr, parsed$src[[i]], envir = envir, enclos = enclos,  :
  unused argument (include_timing = include_timing)
Calls: <Anonymous> ... call_block -> block_exec -> in_dir -> evaluate -> evaluate_call

Reported here:

We have also seen this problem when trying to use knitr inside a packrat cache. In the packrat scenario, we may be using the same version of knitr with multiple versions of evaluate (depending on a particular piece of content).

You probably can avoid this issue with something like:

.default.hooks = list(
  # ...
  evaluate = function(...) evaluate::evaluate(...)
  # ...
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aronatkins commented Oct 4, 2017

Workaround is to re-register the evaluate hook based on the version of evaluate::evaluate available:

knitr::knit_hooks$set(evaluate = evaluate::evaluate)

@yihui yihui added this to the v0.18 milestone Oct 4, 2017
@yihui yihui closed this as completed in d6b53e0 Oct 4, 2017
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yihui commented Oct 4, 2017

Sounds like a reasonable fix. Done. Thanks @aronatkins!

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