- Adds functions we will need for tracking ..stacktraceon/off..
across deep stacks
- Adds functions we will need for pruning according to lobstr::cst
logic
These functions are not yet integrated, that will occur in a
separate commit.
With deep stack traces enabled, whenever then() is called, we need
to grab the current stack, just in case a downstream callback throws
an error and we need to form a deep stack trace.
Previously, we were calling formatStackTrace at the time that we
grab the current stack (i.e. no error has happened yet) because I
wasn't sure whether holding a reference to sys.calls() for a long
time was a good idea from a garbage collection perspective; would it
prevent the stack frame environments from being collected? But the
answer is no, sys.calls() is just calls, which can be confirmed with
.Internal(inspect(sys.calls()).
By deferring the formatStackTrace call to when we actually need to
print the stack trace, we save ourselves a ton of work--it turns out
it's quite expensive to format the stack traces, much more expensive
than sys.calls() alone.
* A copy of yihui's PR for rmarkdown (https://github.com/rstudio/rmarkdown/pull/1171/) to avoid to error "Error in normalizePath: path[1]="": No such file or directory" when running any tutorial
* first try
* limited the scope of the `tryCatch` wrapper to the one important line that needed it; added news item
This was introduced by some changes to shinyapp.js that were necessary
before async outputs and sync outputs were held/flushed together. Now
that async/sync outputs are held/flushed together, these changes are
not necessary and removing them fixes the problem.
The test app is in shiny-examples/205-async-req. I also moved a test
app from manualtests/async/download.R to shiny-examples/204-async-download.
If a downloadHandler content function returns a promise (or future)
then Shiny will wait for the promise to resolve before serving up
the file download.
