Set default tabstop to 2, but only if not changed

ftdetect/polyglot.vim

@@ -2545,7 +2545,7 @@ if !has_key(s:disabled_packages, 'alsaconf')
 endif
 
 if !has_key(s:disabled_packages, 'conf')
-  au BufNewFile,BufRead *.conf,auto.master,config setf conf
+  au BufNewFile,BufRead *.conf,*/etc/hosts,auto.master,config setf conf
 endif
 
 if !has_key(s:disabled_packages, 'master')
@@ -2634,7 +2634,23 @@ if !has_key(s:disabled_packages, 'autoindent')
   " Code below re-implements sleuth for vim-polyglot
   let g:loaded_sleuth = 1
 
-  function! s:guess(lines) abort
+  if &tabstop == 8
+    let &tabstop = 2
+  endif
+
+  func! s:get_shiftwidth(indents) abort
+    let shiftwidth = 0
+    let max_count = 0
+    for [indent, indent_count] in items(a:indents)
+      if indent_count > max_count
+        let shiftwidth = indent
+        let max_count = indent_count
+      endif
+    endfor
+    return shiftwidth
+  endfunc
+
+  func! s:guess(lines) abort
     let options = {}
     let ccomment = 0
     let podcomment = 0
@@ -2644,12 +2660,14 @@ if !has_key(s:disabled_packages, 'autoindent')
     let heredoc = ''
     let minindent = 10
     let spaces_minus_tabs = 0
-    let i = 0
+    let lineno = 0
+    let stack = [0]
+    let indents = { '2': 0, '3': 0, '4': 0, '6': 0, '8': 0 }
 
     for line in a:lines
-      let i += 1
+      let lineno += 1
 
-      if !len(line) || line =~# '^\S+$'
+      if line =~# '^\s*$'
         continue
       endif
 
@@ -2713,51 +2731,64 @@ if !has_key(s:disabled_packages, 'autoindent')
         let heredoc = herematch[1] . '$'
       endif
 
-      let spaces_minus_tabs += line[0] == "\t" ? 1 : -1
-
       if line[0] == "\t"
-        setlocal noexpandtab
-        let &l:shiftwidth=&tabstop
-        let b:sleuth_culprit .= ':' . i
-        return 1
-      elseif line[0] == " "
+        let spaces_minus_tabs -= 1
+      else
+        if line[0] == " "
+          let spaces_minus_tabs += 1
+        endif
         let indent = len(matchstr(line, '^ *'))
-        if indent < minindent && index([2, 3, 4, 6, 8], indent) >= 0
-          let minindent = indent
+        while stack[-1] > indent
+          call remove(stack, -1)
+        endwhile
+
+        let indent_inc = indent - stack[-1]
+
+        if indent_inc == 0 && len(stack) > 1
+          let indent_inc = indent - stack[-2]
+        endif
+
+        if has_key(indents, indent_inc)
+          let indents[indent_inc] += 1
+          let prev_indent = indent
+        endif
+
+        if stack[-1] != indent
+          call add(stack, indent)
         endif
       endif
     endfor
 
-    if minindent < 10
+    if spaces_minus_tabs < 0
+      setlocal noexpandtab
+      let &l:shiftwidth=&tabstop
+      return 1
+    endif
+
+    let shiftwidth = s:get_shiftwidth(indents)
+
+    if shiftwidth > 0
       setlocal expandtab
-      let &l:shiftwidth=minindent
-      if &tabstop == 8
-        let &l:tabstop=minindent
-      endif
-      let b:sleuth_culprit .= ':' . i
+      let &l:shiftwidth=shiftwidth
+      let &l:softtabstop=shiftwidth
       return 1
     endif
 
     return 0
-  endfunction
+  endfunc
 
-  function! s:detect_indent() abort
+  func! s:detect_indent() abort
     if &buftype ==# 'help'
       return
     endif
 
-    if &expandtab
-      " Make tabstop to be synchronized with shiftwidth by default
-      " Some plugins are using &shiftwidth directly or accessing &tabstop
-      if &tabstop != 8 || &shiftwidth == 0
-        let &shiftwidth = &tabstop
-      else
-        let &tabstop = &shiftwidth
-      endif
+    " Do not autodetect indent if language sets it
+    if &l:shiftwidth != &g:shiftwidth
+      return
     endif
 
     let b:sleuth_culprit = expand("<afile>:p")
-    if s:guess(getline(1, 32))
+    if s:guess(getline(1, 128))
       return
     endif
     if s:guess(getline(1, 1024))
@@ -2794,12 +2825,12 @@ if !has_key(s:disabled_packages, 'autoindent')
       let level -= 1
     endwhile
 
-    unlet b:sleuth_culprit
-  endfunction
+    let b:sleuth_culprit = "default"
+  endfunc
 
   set smarttab
 
-  function! SleuthIndicator() abort
+  func! SleuthIndicator() abort
     let sw = &shiftwidth ? &shiftwidth : &tabstop
     if &expandtab
       return 'sw='.sw
@@ -2808,7 +2839,7 @@ if !has_key(s:disabled_packages, 'autoindent')
     else
       return 'sw='.sw.',ts='.&tabstop
     endif
-  endfunction
+  endfunc
 
   augroup polyglot-sleuth
     au!

packages.yaml

@@ -1958,6 +1958,7 @@ filetypes:
   filenames:
   - auto.master
   - config
+  - '*/etc/hosts'
 ---
 name: b
 remote: vim/vim:runtime