patch 8.1.0369: continuation lines cannot contain comments

Problem:    Continuation lines cannot contain comments.
Solution:   Support using "\ .

runtime/doc/repeat.txt

@@ -465,6 +465,16 @@ flag when defining the function, it is not relevant when executing it. >
    .
    :endfunction
    :set cpo-=C
+<
+					*line-continuation-comment*
+To add a comment in between the lines start with '\" '.  Notice the space
+after the double quote.  Example: >
+	let array = [
+		"\ first entry comment
+		\ 'first',
+		"\ second entry comment
+		\ 'second',
+		\ ]
 
 Rationale:
 	Most programs work with a trailing backslash to indicate line
@@ -473,6 +483,14 @@ Rationale:
 		:map xx  asdf\
 <	Therefore the unusual leading backslash is used.
 
+	Starting a comment in a continuation line results in all following
+	continuation lines to be part of the comment.  Since it was like this
+	for a long time, when making it possible to add a comment halfway a
+	sequence of continuation lines, it was not possible to use \", since
+	that was a valid continuation line.  Using '"\ ' comes closest, even
+	though it may look a bit weird.  Requiring the space after the
+	backslash is to make it very unlikely this is a normal comment line.
+
 ==============================================================================
 5. Using Vim packages					*packages*
 

runtime/indent/vim.vim

@@ -10,7 +10,7 @@ endif
 let b:did_indent = 1
 
 setlocal indentexpr=GetVimIndent()
-setlocal indentkeys+==end,=else,=cat,=fina,=END,0\\
+setlocal indentkeys+==end,=else,=cat,=fina,=END,0\\,0=\"\\\ 
 
 let b:undo_indent = "setl indentkeys< indentexpr<"
 
@@ -31,15 +31,17 @@ function GetVimIndent()
   endtry
 endfunc
 
+let s:lineContPat = '^\s*\(\\\|"\\ \)'
+
 function GetVimIndentIntern()
   " Find a non-blank line above the current line.
   let lnum = prevnonblank(v:lnum - 1)
 
-  " If the current line doesn't start with '\' and below a line that starts
-  " with '\', use the indent of the line above it.
+  " If the current line doesn't start with '\' or '"\ ' and below a line that
+  " starts with '\' or '"\ ', use the indent of the line above it.
   let cur_text = getline(v:lnum)
-  if cur_text !~ '^\s*\\'
-    while lnum > 0 && getline(lnum) =~ '^\s*\\'
+  if cur_text !~ s:lineContPat
+    while lnum > 0 && getline(lnum) =~ s:lineContPat
       let lnum = lnum - 1
     endwhile
   endif
@@ -51,10 +53,10 @@ function GetVimIndentIntern()
   let prev_text = getline(lnum)
 
   " Add a 'shiftwidth' after :if, :while, :try, :catch, :finally, :function
-  " and :else.  Add it three times for a line that starts with '\' after
-  " a line that doesn't (or g:vim_indent_cont if it exists).
+  " and :else.  Add it three times for a line that starts with '\' or '"\ '
+  " after a line that doesn't (or g:vim_indent_cont if it exists).
   let ind = indent(lnum)
-  if cur_text =~ '^\s*\\' && v:lnum > 1 && prev_text !~ '^\s*\\'
+  if cur_text =~ s:lineContPat && v:lnum > 1 && prev_text !~ s:lineContPat
     if exists("g:vim_indent_cont")
       let ind = ind + g:vim_indent_cont
     else

src/ex_cmds2.c

@@ -4864,17 +4864,21 @@ getsourceline(int c UNUSED, void *cookie, int indent UNUSED)
 	/* compensate for the one line read-ahead */
 	--sourcing_lnum;
 
-	/* Get the next line and concatenate it when it starts with a
-	 * backslash. We always need to read the next line, keep it in
-	 * sp->nextline. */
+	// Get the next line and concatenate it when it starts with a
+	// backslash. We always need to read the next line, keep it in
+	// sp->nextline.
+	/* Also check for a comment in between continuation lines: "\ */
 	sp->nextline = get_one_sourceline(sp);
-	if (sp->nextline != NULL && *(p = skipwhite(sp->nextline)) == '\\')
+	if (sp->nextline != NULL
+		&& (*(p = skipwhite(sp->nextline)) == '\\'
+			      || (p[0] == '"' && p[1] == '\\' && p[2] == ' ')))
 	{
 	    garray_T    ga;
 
 	    ga_init2(&ga, (int)sizeof(char_u), 400);
 	    ga_concat(&ga, line);
-	    ga_concat(&ga, p + 1);
+	    if (*p == '\\')
+		ga_concat(&ga, p + 1);
 	    for (;;)
 	    {
 		vim_free(sp->nextline);
@@ -4882,18 +4886,21 @@ getsourceline(int c UNUSED, void *cookie, int indent UNUSED)
 		if (sp->nextline == NULL)
 		    break;
 		p = skipwhite(sp->nextline);
-		if (*p != '\\')
-		    break;
-		/* Adjust the growsize to the current length to speed up
-		 * concatenating many lines. */
-		if (ga.ga_len > 400)
+		if (*p == '\\')
 		{
-		    if (ga.ga_len > 8000)
-			ga.ga_growsize = 8000;
-		    else
-			ga.ga_growsize = ga.ga_len;
+		    // Adjust the growsize to the current length to speed up
+		    // concatenating many lines.
+		    if (ga.ga_len > 400)
+		    {
+			if (ga.ga_len > 8000)
+			    ga.ga_growsize = 8000;
+			else
+			    ga.ga_growsize = ga.ga_len;
+		    }
+		    ga_concat(&ga, p + 1);
 		}
-		ga_concat(&ga, p + 1);
+		else if (p[0] != '"' || p[1] != '\\' || p[2] != ' ')
+		    break;
 	    }
 	    ga_append(&ga, NUL);
 	    vim_free(line);

src/testdir/test_eval_stuff.vim

@@ -42,3 +42,14 @@ func Test_mkdir_p()
   call delete('Xfile')
   call delete('Xmkdir', 'rf')
 endfunc
+
+func Test_line_continuation()
+  let array = [5,
+	"\ ignore this
+	\ 6,
+	"\ more to ignore
+	"\ more moreto ignore
+	\ ]
+	"\ and some more
+  call assert_equal([5, 6], array)
+endfunc

src/version.c

@@ -794,6 +794,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    369,
 /**/
     368,
 /**/