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
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.
- Moved (in|de)crementBusyCount calls out of Context and into Observer
- decrementBusyCount is (effectively) deferred for async observers until
the async operation is complete
- invalidateLater didn't force(session), almost certainly was buggy
- invalidateLater, reactiveTimer, and manageInputs all now use a new
session$cycleStartAction, which delays their effect until observers
(including async ones) are done executing
* style & formatting. fixes#1859
* prepare `choices` in `updateSelectizeInput()` as per discussion in #1861
* remove duplicated block in selectizeJSON, simply `lab` assignement logic
* Fix#1824: HEAD request on static files causes app to stop
The problem was that for HEAD requests specifically, we implement
an explicit Content-Length header (normally we let httpuv figure
out the Content-Length based on the content, but for HEAD we don't
return any content but still want to include the Content-Length).
The Content-Length header was only implemented correctly for string
values, not for raw vectors or file-by-path. This change implements
the value correctly for all currently valid httpuv content.
* Update NEWS
* Code review feedback
