patch 8.2.4512: the find_tags_in_file() function is much too long

Problem:    The find_tags_in_file() function is much too long.
Solution:   Refactor into multiple smaller functions. (Yegappan Lakshmanan,
            closes #9892)

Filelist

@@ -198,7 +198,6 @@ SRC_ALL =	\
 		src/testdir/view_util.vim \
 		src/testdir/test[0-9]*.ok \
 		src/testdir/test77a.ok \
-		src/testdir/test83-tags? \
 		src/testdir/test77a.com \
 		src/testdir/test_*.vim \
 		src/testdir/python2/*.py \
@@ -1000,6 +999,7 @@ LANG_GEN = \
 		runtime/doc/*-tr.1 \
 		runtime/doc/*-tr.UTF-8.1 \
 		runtime/lang/README.txt \
+		runtime/lang/Makefile \
 		runtime/lang/menu_*.vim \
 		runtime/keymap/README.txt \
 		runtime/keymap/*.vim \

src/Makefile

@@ -3010,7 +3010,6 @@ shadow:	runtime pixmaps
 				 ../../testdir/sautest \
 				 ../../testdir/samples \
 				 ../../testdir/dumps \
-				 ../../testdir/test83-tags? \
 				 ../../testdir/*.ok \
 				 ../../testdir/testluaplugin \
 				 .

src/quickfix.c

@@ -8106,8 +8106,7 @@ hgr_search_file(
 
 	// Convert a line if 'encoding' is not utf-8 and
 	// the line contains a non-ASCII character.
-	if (p_vc->vc_type != CONV_NONE
+	if (p_vc->vc_type != CONV_NONE && has_non_ascii(IObuff))
-		&& has_non_ascii(IObuff))
 	{
 	    line = string_convert(p_vc, IObuff, NULL);
 	    if (line == NULL)

src/testdir/test83-tags2

@@ -1,2 +0,0 @@
-!_TAG_FILE_ENCODING	cp932	//
-‚`‚a‚b	Xtags2.txt	/‚`‚a‚b

src/testdir/test83-tags3

@@ -1,102 +0,0 @@
-!_TAG_FILE_SORTED	1	//
-!_TAG_FILE_ENCODING	cp932	//
-abc1	Xtags3.txt	/‚`‚a‚b
-abc2	Xtags3.txt	/‚`‚a‚b
-abc3	Xtags3.txt	/‚`‚a‚b
-abc4	Xtags3.txt	/‚`‚a‚b
-abc5	Xtags3.txt	/‚`‚a‚b
-abc6	Xtags3.txt	/‚`‚a‚b
-abc7	Xtags3.txt	/‚`‚a‚b
-abc8	Xtags3.txt	/‚`‚a‚b
-abc9	Xtags3.txt	/‚`‚a‚b
-abc10	Xtags3.txt	/‚`‚a‚b
-abc11	Xtags3.txt	/‚`‚a‚b
-abc12	Xtags3.txt	/‚`‚a‚b
-abc13	Xtags3.txt	/‚`‚a‚b
-abc14	Xtags3.txt	/‚`‚a‚b
-abc15	Xtags3.txt	/‚`‚a‚b
-abc16	Xtags3.txt	/‚`‚a‚b
-abc17	Xtags3.txt	/‚`‚a‚b
-abc18	Xtags3.txt	/‚`‚a‚b
-abc19	Xtags3.txt	/‚`‚a‚b
-abc20	Xtags3.txt	/‚`‚a‚b
-abc21	Xtags3.txt	/‚`‚a‚b
-abc22	Xtags3.txt	/‚`‚a‚b
-abc23	Xtags3.txt	/‚`‚a‚b
-abc24	Xtags3.txt	/‚`‚a‚b
-abc25	Xtags3.txt	/‚`‚a‚b
-abc26	Xtags3.txt	/‚`‚a‚b
-abc27	Xtags3.txt	/‚`‚a‚b
-abc28	Xtags3.txt	/‚`‚a‚b
-abc29	Xtags3.txt	/‚`‚a‚b
-abc30	Xtags3.txt	/‚`‚a‚b
-abc31	Xtags3.txt	/‚`‚a‚b
-abc32	Xtags3.txt	/‚`‚a‚b
-abc33	Xtags3.txt	/‚`‚a‚b
-abc34	Xtags3.txt	/‚`‚a‚b
-abc35	Xtags3.txt	/‚`‚a‚b
-abc36	Xtags3.txt	/‚`‚a‚b
-abc37	Xtags3.txt	/‚`‚a‚b
-abc38	Xtags3.txt	/‚`‚a‚b
-abc39	Xtags3.txt	/‚`‚a‚b
-abc40	Xtags3.txt	/‚`‚a‚b
-abc41	Xtags3.txt	/‚`‚a‚b
-abc42	Xtags3.txt	/‚`‚a‚b
-abc43	Xtags3.txt	/‚`‚a‚b
-abc44	Xtags3.txt	/‚`‚a‚b
-abc45	Xtags3.txt	/‚`‚a‚b
-abc46	Xtags3.txt	/‚`‚a‚b
-abc47	Xtags3.txt	/‚`‚a‚b
-abc48	Xtags3.txt	/‚`‚a‚b
-abc49	Xtags3.txt	/‚`‚a‚b
-abc50	Xtags3.txt	/‚`‚a‚b
-abc51	Xtags3.txt	/‚`‚a‚b
-abc52	Xtags3.txt	/‚`‚a‚b
-abc53	Xtags3.txt	/‚`‚a‚b
-abc54	Xtags3.txt	/‚`‚a‚b
-abc55	Xtags3.txt	/‚`‚a‚b
-abc56	Xtags3.txt	/‚`‚a‚b
-abc57	Xtags3.txt	/‚`‚a‚b
-abc58	Xtags3.txt	/‚`‚a‚b
-abc59	Xtags3.txt	/‚`‚a‚b
-abc60	Xtags3.txt	/‚`‚a‚b
-abc61	Xtags3.txt	/‚`‚a‚b
-abc62	Xtags3.txt	/‚`‚a‚b
-abc63	Xtags3.txt	/‚`‚a‚b
-abc64	Xtags3.txt	/‚`‚a‚b
-abc65	Xtags3.txt	/‚`‚a‚b
-abc66	Xtags3.txt	/‚`‚a‚b
-abc67	Xtags3.txt	/‚`‚a‚b
-abc68	Xtags3.txt	/‚`‚a‚b
-abc69	Xtags3.txt	/‚`‚a‚b
-abc70	Xtags3.txt	/‚`‚a‚b
-abc71	Xtags3.txt	/‚`‚a‚b
-abc72	Xtags3.txt	/‚`‚a‚b
-abc73	Xtags3.txt	/‚`‚a‚b
-abc74	Xtags3.txt	/‚`‚a‚b
-abc75	Xtags3.txt	/‚`‚a‚b
-abc76	Xtags3.txt	/‚`‚a‚b
-abc77	Xtags3.txt	/‚`‚a‚b
-abc78	Xtags3.txt	/‚`‚a‚b
-abc79	Xtags3.txt	/‚`‚a‚b
-abc80	Xtags3.txt	/‚`‚a‚b
-abc81	Xtags3.txt	/‚`‚a‚b
-abc82	Xtags3.txt	/‚`‚a‚b
-abc83	Xtags3.txt	/‚`‚a‚b
-abc84	Xtags3.txt	/‚`‚a‚b
-abc85	Xtags3.txt	/‚`‚a‚b
-abc86	Xtags3.txt	/‚`‚a‚b
-abc87	Xtags3.txt	/‚`‚a‚b
-abc88	Xtags3.txt	/‚`‚a‚b
-abc89	Xtags3.txt	/‚`‚a‚b
-abc90	Xtags3.txt	/‚`‚a‚b
-abc91	Xtags3.txt	/‚`‚a‚b
-abc92	Xtags3.txt	/‚`‚a‚b
-abc93	Xtags3.txt	/‚`‚a‚b
-abc94	Xtags3.txt	/‚`‚a‚b
-abc95	Xtags3.txt	/‚`‚a‚b
-abc96	Xtags3.txt	/‚`‚a‚b
-abc97	Xtags3.txt	/‚`‚a‚b
-abc98	Xtags3.txt	/‚`‚a‚b
-abc99	Xtags3.txt	/‚`‚a‚b
-abc100	Xtags3.txt	/‚`‚a‚b

src/testdir/test_tagjump.vim

@@ -230,7 +230,6 @@ func Test_tag_symbolic()
 endfunc
 
 " Tests for tag search with !_TAG_FILE_ENCODING.
-" Depends on the test83-tags2 and test83-tags3 files.
 func Test_tag_file_encoding()
   if has('vms')
     throw 'Skipped: does not work on VMS'
@@ -262,18 +261,31 @@ func Test_tag_file_encoding()
 
   " case2:
   new
-  set tags=test83-tags2
+  let content = ['!_TAG_FILE_ENCODING	cp932	//',
+        \ "\x82`\x82a\x82b	Xtags2.txt	/\x82`\x82a\x82b"]
+  call writefile(content, 'Xtags')
+  set tags=Xtags
   tag /.ＢＣ
   call assert_equal('Xtags2.txt', expand('%:t'))
   call assert_equal('ＡＢＣ', getline('.'))
+  call delete('Xtags')
   close
 
   " case3:
   new
-  set tags=test83-tags3
+  let contents = [
+      \ "!_TAG_FILE_SORTED	1	//",
+      \ "!_TAG_FILE_ENCODING	cp932	//"]
+  for i in range(1, 100)
+      call add(contents, 'abc' .. i
+            \ .. "	Xtags3.txt	/\x82`\x82a\x82b")
+  endfor
+  call writefile(contents, 'Xtags')
+  set tags=Xtags
   tag abc50
   call assert_equal('Xtags3.txt', expand('%:t'))
   call assert_equal('ＡＢＣ', getline('.'))
+  call delete('Xtags')
   close
 
   set tags&
@@ -324,6 +336,7 @@ func Test_tagjump_etags()
         \ ], 'Xtags2')
   tag main
   call assert_equal(2, line('.'))
+  call assert_fails('tag bar', 'E426:')
 
   " corrupted tag line
   call writefile([
@@ -349,6 +362,27 @@ func Test_tagjump_etags()
 	\ ], 'Xtags')
   call assert_fails('tag foo', 'E431:')
 
+  " end of file after a CTRL-L line
+  call writefile([
+	\ "\x0c",
+        \ "Xmain.c,64",
+        \ "void foo() {}\x7ffoo\x011,0",
+	\ "\x0c",
+	\ ], 'Xtags')
+  call assert_fails('tag main', 'E426:')
+
+  " error in an included tags file
+  call writefile([
+        \ "\x0c",
+        \ "Xtags2,include"
+        \ ], 'Xtags')
+  call writefile([
+        \ "\x0c",
+        \ "Xmain.c,64",
+        \ "void foo() {}",
+        \ ], 'Xtags2')
+  call assert_fails('tag foo', 'E431:')
+
   call delete('Xtags')
   call delete('Xtags2')
   call delete('Xmain.c')
@@ -1432,6 +1466,11 @@ func Test_tagfile_errors()
         \ "foo Xfile 1"], 'Xtags')
   call assert_fails('tag foo', 'E431:')
 
+  " file name and search pattern are not separated by a tab
+  call writefile(["!_TAG_FILE_ENCODING\tutf-8\t//",
+        \ "foo\tXfile 1;"], 'Xtags')
+  call assert_fails('tag foo', 'E431:')
+
   call delete('Xtags')
   call delete('Xfile')
   set tags&

src/version.c

@@ -754,6 +754,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    4512,
 /**/
     4511,
 /**/