App launching error disappeared with new R session.

[xhd...@umd.edu]

When I'm developing my Shiny app in RStudio, it became more and more often I met this error after launching the app:

> runApp('shiny/app')

Listening on http://127.0.0.1:3542

Warning: Error in <Anonymous>: unable to find an inherited method for function ‘span’ for signature ‘"shiny.tag"’

Stack trace (innermost first):

    74: <Anonymous>

    73: span

    72: isTRUE

    71: is.singleton

    70: func

    69: rewriteTags

    68: takeSingletons

    67: processDeps

    66: showNotification

    65: observeEventHandler [/Users/xhdong/Projects/ctmm-Shiny/shiny/app/server.R#104]

     1: runApp

ERROR: [on_request_read] connection reset by peer

Then if I restart the R session the error will disappear:

> shiny::runApp('shiny/app')

Loading required package: shiny

Loading required package: pacman

Listening on http://127.0.0.1:3456

Looks like previously Shiny is not even loaded. I checked RStudio logs but didn't find anything related.

[Joe Cheng]

This looks like a function name collision--like another package you've attached has a function named "span". When this happens, use ?span to see what other package you're using has such a function (besides htmltools and shiny). You should be able to work around this by explicitly using shiny::span() or htmltools::span() instead of just span().

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[xhd...@umd.edu]

That was also my first guess. I have a RStudio addin to search all functions, symbols in all packages installed. So I fired it up and checked with "span". You can see from the attachment that only libraries with "span" is htmltools, shiny and geoshpere. I tried to load library of "geosphere" first then launch the app, but there was no error. 

When I first met the problem, the error message indicated that problem was with this line:

showNotification(span(icon("spinner fa-spin"), "Importing data..."), type = "message", duration = NULL)

I changed "span" into "tags$span". Then when the problem appear again, it was about a second occurrence of similar usage:

showNotification(span(icon("spinner fa-spin"), "Downloading studies..."), type = "message", duration = NULL)

So it definitely was caused by naming conflict with "span", but I'm not sure which package caused that, since I have searched all my packages. And I believe there is no variable named "span" in my global environment.

Anyway, the problem should be solved with using full qualified name. Thanks!

[xhd...@umd.edu]

Uploading attachment seemed always cause problem, here is the screen shot I wanted to upload: