Remove `tabspaces` config option

This completely removes the tabspaces option from the Alacritty
configuration, due to frequent misuse of it. Based on some research,
none of the terminal emulators support setting the value for tabspaces
or read the terminfo to determine init_tabs value at startup. The tested
terminal emulators were URxvt, XTerm, and Termite.

1 files changed, 7 insertions, 8 deletions

diff --git a/alacritty_terminal/src/term/mod.rs b/alacritty_terminal/src/term/mod.rs
index f198c59b..d545d686 100644
--- a/alacritty_terminal/src/term/mod.rs
+++ b/alacritty_terminal/src/term/mod.rs
@@ -47,6 +47,9 @@ const BRACKET_PAIRS: [(char, char); 4] = [('(', ')'), ('[', ']'), ('{', '}'), ('
 /// Max size of the window title stack.
 const TITLE_STACK_MAX_DEPTH: usize = 4096;
 
+/// Default tab interval, corresponding to terminfo `it` value.
+const INITIAL_TABSTOPS: usize = 8;
+
 /// A type that can expand a given point to a region
 ///
 /// Usually this is implemented for some 2-D array type since
@@ -916,8 +919,7 @@ impl<T> Term<T> {
         let grid = Grid::new(num_lines, num_cols, history_size, Cell::default());
         let alt = Grid::new(num_lines, num_cols, 0 /* scroll history */, Cell::default());
 
-        let tabspaces = config.tabspaces();
-        let tabs = TabStops::new(grid.num_cols(), tabspaces);
+        let tabs = TabStops::new(grid.num_cols());
 
         let scroll_region = Line(0)..grid.num_lines();
 
@@ -2154,16 +2156,14 @@ impl<T: EventListener> Handler for Term<T> {
 
 struct TabStops {
     tabs: Vec<bool>,
-    tabspaces: usize,
 }
 
 impl TabStops {
     #[inline]
-    fn new(num_cols: Column, tabspaces: usize) -> TabStops {
+    fn new(num_cols: Column) -> TabStops {
         TabStops {
-            tabspaces,
             tabs: IndexRange::from(Column(0)..num_cols)
-                .map(|i| (*i as usize) % tabspaces == 0)
+                .map(|i| (*i as usize) % INITIAL_TABSTOPS == 0)
                 .collect::<Vec<bool>>(),
         }
     }
@@ -2179,10 +2179,9 @@ impl TabStops {
     /// Increase tabstop capacity.
     #[inline]
     fn resize(&mut self, num_cols: Column) {
-        let tabspaces = self.tabspaces;
         let mut index = self.tabs.len();
         self.tabs.resize_with(num_cols.0, || {
-            let is_tabstop = index % tabspaces == 0;
+            let is_tabstop = index % INITIAL_TABSTOPS == 0;
             index += 1;
             is_tabstop
         });