How to identify all the loaded ftplugins for the current file?

Question

I have installed a lot of plugins and each may has its own ftplugin settings. What is the way to find out all ftplugin scripts that have been sourced for the current buffer?

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Just to summarize the solution based on the accepted answer:

:exe 'filter #ftplugin/' . &filetype . '.vim$# scriptnames'

Answer 1

I don't know of a direct way to get a list of only the things loaded for the current buffer based on filetype, but :scriptnames will list everything that's been loaded, including system/default plugins, runtime scripts, etc.

To figure out what's additionally autoloaded for a specific filetype, start Vim with no arguments, run :scriptnames, then open a file of the type you care about, and run :scriptnames again. If anything new was autoloaded for the filetype, you'll see it appended to the list the second time.

You can capture the output (to paste into a buffer, for example) with redir:

:redir @a
:scriptnames
:redir END

You'll see the output displayed, but it will also be copied to register a. You can paste that into a buffer with "ap.

Answer 2

A manual way might be to use script debugging. Edit a file with the :debug command, say :debug e foo.c. Then set breakpoints for all .vim files using breakadd file *.vim. Repeatedly issue the :cont command:

Entering Debug mode.  Type "cont" to continue.
cmd: e foo.c
>breakadd file *.vim
"foo.c" [New File]
Breakpoint in "/usr/local/Cellar/vim/8.0.1171/share/vim/vim80/ftplugin/c.vim" line 1
/usr/local/Cellar/vim/8.0.1171/share/vim/vim80/ftplugin/c.vim
line 7: if exists("b:did_ftplugin")
> c
Breakpoint in "/usr/local/Cellar/vim/8.0.1171/share/vim/vim80/indent/c.vim" line 1
/usr/local/Cellar/vim/8.0.1171/share/vim/vim80/indent/c.vim
line 7: if exists("b:did_indent")
>
Breakpoint in "/usr/local/Cellar/vim/8.0.1171/share/vim/vim80/syntax/c.vim" line 1
/usr/local/Cellar/vim/8.0.1171/share/vim/vim80/syntax/c.vim
line 7: if exists("b:current_syntax")
>
Breakpoint in "/Users/muru/.vim/plugged/tagbar/plugin/tagbar.vim" line 1
/Users/muru/.vim/plugged/tagbar/plugin/tagbar.vim
line 21: scriptencoding utf-8
...

This doesn't restrict itself to ftplugins, but it does show which plugins will be loaded just by editing this file. The breakadd pattern can changed to something like breakadd file */ftplugin/*.vim if you're only interested in files in an ftplugin directory somewhere.