patch 8.0.0613: the conf filetype is used before ftdetect from packages

Problem:    The conf filetype detection is done before ftdetect scripts from
            packages that are added later.
Solution:   Add the FALLBACK argument to :setfiletype. (closes #1679,
            closes #1693)

5 files changed, 58 insertions, 2 deletions

diff --git a/src/Makefile b/src/Makefile
index ddb61dc08..8fa004e8f 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -2133,6 +2133,7 @@ test_arglist \
 	test_feedkeys \
 	test_file_perm \
 	test_fileformat \
+	test_filetype \
 	test_filter_cmd \
 	test_filter_map \
 	test_findfile \
diff --git a/src/ex_docmd.c b/src/ex_docmd.c
index 13d5fe495..2c9c8782e 100644
--- a/src/ex_docmd.c
+++ b/src/ex_docmd.c
@@ -12172,13 +12172,22 @@ ex_filetype(exarg_T *eap)
 }
 
 /*
- * ":setfiletype {name}"
+ * ":setfiletype [FALLBACK] {name}"
  */
     static void
 ex_setfiletype(exarg_T *eap)
 {
     if (!did_filetype)
-	set_option_value((char_u *)"filetype", 0L, eap->arg, OPT_LOCAL);
+    {
+	char_u *arg = eap->arg;
+
+	if (STRNCMP(arg, "FALLBACK ", 9) == 0)
+	    arg += 9;
+
+	set_option_value((char_u *)"filetype", 0L, arg, OPT_LOCAL);
+	if (arg != eap->arg)
+	    did_filetype = FALSE;
+    }
 }
 #endif
 
diff --git a/src/testdir/test_alot.vim b/src/testdir/test_alot.vim
index e961e9945..fec22714e 100644
--- a/src/testdir/test_alot.vim
+++ b/src/testdir/test_alot.vim
@@ -16,6 +16,7 @@ source test_expr.vim
 source test_feedkeys.vim
 source test_file_perm.vim
 source test_fileformat.vim
+source test_filetype.vim
 source test_filter_cmd.vim
 source test_filter_map.vim
 source test_findfile.vim
diff --git a/src/testdir/test_filetype.vim b/src/testdir/test_filetype.vim
new file mode 100644
index 000000000..818603b18
--- /dev/null
+++ b/src/testdir/test_filetype.vim
@@ -0,0 +1,43 @@
+" Test :setfiletype
+
+func Test_detection()
+  filetype on
+  augroup filetypedetect
+    au BufNewFile,BufRead *	call assert_equal(1, did_filetype())
+  augroup END
+  new something.vim
+  call assert_equal('vim', &filetype)
+
+  bwipe!
+  filetype off
+endfunc
+
+func Test_conf_type()
+  filetype on
+  call writefile(['# some comment', 'must be conf'], 'Xfile')
+  augroup filetypedetect
+    au BufNewFile,BufRead *	call assert_equal(0, did_filetype())
+  augroup END
+  split Xfile
+  call assert_equal('conf', &filetype)
+
+  bwipe!
+  call delete('Xfile')
+  filetype off
+endfunc
+
+func Test_other_type()
+  filetype on
+  augroup filetypedetect
+    au BufNewFile,BufRead *	call assert_equal(0, did_filetype())
+    au BufNewFile,BufRead Xfile	setf testfile
+    au BufNewFile,BufRead *	call assert_equal(1, did_filetype())
+  augroup END
+  call writefile(['# some comment', 'must be conf'], 'Xfile')
+  split Xfile
+  call assert_equal('testfile', &filetype)
+
+  bwipe!
+  call delete('Xfile')
+  filetype off
+endfunc
diff --git a/src/version.c b/src/version.c
index 91cd50052..f5b5732ad 100644
--- a/src/version.c
+++ b/src/version.c
@@ -765,6 +765,8 @@ static char *(features[]) =
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    613,
+/**/
     612,
 /**/
     611,