From 28787da1d1fbc5efcb9e382af87af15ce66e8996 Mon Sep 17 00:00:00 2001
From: Bjoern Klaas <subs@bklaas.name>
Date: Thu, 15 Oct 2020 09:56:09 +0200
Subject: [PATCH 1/3] find comments after optional [.*] at \begin{frame}

---
 autoload/vimtex/fold/envs.vim | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/autoload/vimtex/fold/envs.vim b/autoload/vimtex/fold/envs.vim
index 143bfdd163..c040d64a05 100644
--- a/autoload/vimtex/fold/envs.vim
+++ b/autoload/vimtex/fold/envs.vim
@@ -178,7 +178,7 @@ function! s:folder.parse_caption_frame(line) abort dict " {{{1
   endwhile
 
   " If no caption found, check for a caption comment
-  return matchstr(a:line,'\\begin\*\?{.*}\s*%\s*\zs.*')
+  return matchstr(a:line,'\\begin\*\?{.*}\(\[.*\]\)\?\s*%\s*\zs.*')
 endfunction
 
 " }}}1

From 52c2cdcb7659e749b8145b3f7a143d96beb0972e Mon Sep 17 00:00:00 2001
From: Bjoern Klaas <subs@bklaas.name>
Date: Thu, 15 Oct 2020 09:58:50 +0200
Subject: [PATCH 2/3] show frametitle and framesubtitle on folds

---
 autoload/vimtex/fold/envs.vim | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/autoload/vimtex/fold/envs.vim b/autoload/vimtex/fold/envs.vim
index c040d64a05..c68cc3b0d7 100644
--- a/autoload/vimtex/fold/envs.vim
+++ b/autoload/vimtex/fold/envs.vim
@@ -171,8 +171,14 @@ function! s:folder.parse_caption_frame(line) abort dict " {{{1
   let i = v:foldstart
   while i <= v:foldend
     if getline(i) =~# '^\s*\\frametitle'
-      return matchstr(getline(i),
+      let frametitle = matchstr(getline(i),
             \ '^\s*\\frametitle\(\[.*\]\)\?{\zs.\{-1,}\ze\(}\s*\)\?$')
+      if i+1 <= v:foldend && getline(i+1) =~# '^\s*\\framesubtitle'
+        let framesubtitle = matchstr(getline(i+1),
+              \ '^\s*\\framesubtitle\(\[.*\]\)\?{\zs.\{-1,}\ze\(}\s*\)\?$')
+        return printf('%S: %S', frametitle, framesubtitle)
+      end
+      return frametitle
     end
     let i += 1
   endwhile

From b51ea215fc0bafb32ab7f12dd47affdda3b8ac83 Mon Sep 17 00:00:00 2001
From: Bjoern Klaas <subs@bklaas.name>
Date: Mon, 8 Feb 2021 00:21:58 +0100
Subject: [PATCH 3/3] add a test for beamer frame folding

---
 test/test-folding/main.tex | 13 +++++++++++++
 test/test-folding/test.vim |  9 +++++++++
 2 files changed, 22 insertions(+)

diff --git a/test/test-folding/main.tex b/test/test-folding/main.tex
index 103dfcc2df..29f1aa0886 100644
--- a/test/test-folding/main.tex
+++ b/test/test-folding/main.tex
@@ -201,4 +201,17 @@ \section{test 3}
     \end{proof}
 \end{enumerate}
 
+% The frames need to be in this order for the test to pass. This is likely a
+% bug in vim, see https://github.com/lervag/vimtex/pull/1830#issuecomment-775527621
+\begin{frame}
+  \frametitle{Title}
+  \framesubtitle{Subtitle}
+
+  hello world
+\end{frame}
+
+\begin{frame}[noframenumbering]  % Title page
+  hello world
+\end{frame}
+
 \end{document}
diff --git a/test/test-folding/test.vim b/test/test-folding/test.vim
index f0ce67731f..2946b79e80 100644
--- a/test/test-folding/test.vim
+++ b/test/test-folding/test.vim
@@ -56,6 +56,15 @@ call vimtex#test#assert_equal(3, foldlevel(186))
 call vimtex#test#assert_equal(1, foldlevel(190))
 call vimtex#test#assert_equal(2, foldlevel(202))
 
+call vimtex#test#assert_equal(2, foldlevel(206))
+call vimtex#test#assert_equal(
+      \ '\begin{frame}       Title: Subtitle',
+      \ foldtextresult(206))
+call vimtex#test#assert_equal(2, foldlevel(213))
+call vimtex#test#assert_equal(
+      \ '\begin{frame}       Title page',
+      \ foldtextresult(213))
+
 call vimtex#test#assert_equal(1, foldlevel(line('$')-1))
 
 quit!