feat: tiebreak config function (#1401)

Co-authored-by: Simon Hauser <Simon-Hauser@outlook.de>

doc/telescope.txt

@@ -74,6 +74,20 @@ telescope.setup({opts})                                    *telescope.setup()*
         - "descending" (default)
         - "ascending"
 
+                                              *telescope.defaults.tiebreak*
+    tiebreak: ~
+        A function that determines how to break a tie when two entries have
+        the same score.
+        Having a function that always returns false would keep the entries in
+        the order they are found, so existing_entry before current_entry.
+        Vice versa always returning true would place the current_entry
+        before the existing_entry.
+
+        Signature: function(current_entry, existing_entry, prompt) -> boolean
+
+        Default: function that breaks the tie based on the length of the
+                 entry's ordinal
+
                                     *telescope.defaults.selection_strategy*
     selection_strategy: ~
         Determines how the cursor acts after each sort iteration.

lua/telescope/config.lua

@@ -153,6 +153,25 @@ append(
   - "ascending"]]
 )
 
+append(
+  "tiebreak",
+  function(current_entry, existing_entry, _)
+    return #current_entry.ordinal < #existing_entry.ordinal
+  end,
+  [[
+  A function that determines how to break a tie when two entries have
+  the same score.
+  Having a function that always returns false would keep the entries in
+  the order they are found, so existing_entry before current_entry.
+  Vice versa always returning true would place the current_entry
+  before the existing_entry.
+
+  Signature: function(current_entry, existing_entry, prompt) -> boolean
+
+  Default: function that breaks the tie based on the length of the
+           entry's ordinal]]
+)
+
 append(
   "selection_strategy",
   "reset",

lua/telescope/entry_manager.lua

@@ -105,7 +105,7 @@ function EntryManager:_append_container(picker, new_container, should_update)
   end
 end
 
-function EntryManager:add_entry(picker, score, entry)
+function EntryManager:add_entry(picker, score, entry, prompt)
   score = score or 0
 
   local max_res = self.max_results
@@ -137,7 +137,7 @@ function EntryManager:add_entry(picker, score, entry)
       return self:_insert_container_before(picker, index, node, new_container)
     end
 
-    if score < 1 and container[2] == score and #entry.ordinal < #container[1].ordinal then
+    if score < 1 and container[2] == score and picker.tiebreak(entry, container[1], prompt) then
       return self:_insert_container_before(picker, index, node, new_container)
     end
 

lua/telescope/pickers.lua

@@ -105,6 +105,7 @@ function Picker:new(opts)
 
     scroll_strategy = get_default(opts.scroll_strategy, config.values.scroll_strategy),
     sorting_strategy = get_default(opts.sorting_strategy, config.values.sorting_strategy),
+    tiebreak = get_default(opts.tiebreak, config.values.tiebreak),
     selection_strategy = get_default(opts.selection_strategy, config.values.selection_strategy),
 
     layout_strategy = layout_strategy,
@@ -1210,7 +1211,8 @@ function Picker:get_result_processor(find_id, prompt, status_updater)
   local count = 0
 
   local cb_add = function(score, entry)
-    self.manager:add_entry(self, score, entry)
+    -- may need the prompt for tiebreak
+    self.manager:add_entry(self, score, entry, prompt)
     status_updater { completed = false }
   end
 

lua/tests/automated/entry_manager_spec.lua

@@ -6,7 +6,7 @@ describe("process_result", function()
   it("works with one entry", function()
     local manager = EntryManager:new(5, nil)
 
-    manager:add_entry(nil, 1, "hello")
+    manager:add_entry(nil, 1, "hello", "")
 
     eq(1, manager:get_score(1))
   end)
@@ -14,8 +14,8 @@ describe("process_result", function()
   it("works with two entries", function()
     local manager = EntryManager:new(5, nil)
 
-    manager:add_entry(nil, 1, "hello")
+    manager:add_entry(nil, 1, "hello", "")
-    manager:add_entry(nil, 2, "later")
+    manager:add_entry(nil, 2, "later", "")
 
     eq(2, manager.linked_states.size)
 
@@ -30,7 +30,7 @@ describe("process_result", function()
     end)
 
     assert(called_count == 0)
-    manager:add_entry(nil, 1, "hello")
+    manager:add_entry(nil, 1, "hello", "")
     assert(called_count == 1)
   end)
 
@@ -41,8 +41,8 @@ describe("process_result", function()
     end)
 
     assert(called_count == 0)
-    manager:add_entry(nil, 1, "hello")
+    manager:add_entry(nil, 1, "hello", "")
-    manager:add_entry(nil, 2, "world")
+    manager:add_entry(nil, 2, "world", "")
     assert(called_count == 2)
   end)
 
@@ -51,8 +51,8 @@ describe("process_result", function()
     local manager = EntryManager:new(5, function()
       called_count = called_count + 1
     end)
-    manager:add_entry(nil, 5, "worse result")
+    manager:add_entry(nil, 5, "worse result", "")
-    manager:add_entry(nil, 2, "better result")
+    manager:add_entry(nil, 2, "better result", "")
 
     eq("better result", manager:get_entry(1))
     eq("worse result", manager:get_entry(2))
@@ -65,8 +65,8 @@ describe("process_result", function()
     local manager = EntryManager:new(1, function()
       called_count = called_count + 1
     end)
-    manager:add_entry(nil, 2, "better result")
+    manager:add_entry(nil, 2, "better result", "")
-    manager:add_entry(nil, 5, "worse result")
+    manager:add_entry(nil, 5, "worse result", "")
 
     eq("better result", manager:get_entry(1))
     eq(1, called_count)
@@ -92,7 +92,8 @@ describe("process_result", function()
           rawset(t, k, val)
           return val
         end,
-      })
+      }),
+      ""
     )
 
     eq("wow", manager:get_ordinal(1))
@@ -105,9 +106,9 @@ describe("process_result", function()
   it("should not loop a bunch", function()
     local info = {}
     local manager = EntryManager:new(5, nil, info)
-    manager:add_entry(nil, 4, "better result")
+    manager:add_entry(nil, 4, "better result", "")
-    manager:add_entry(nil, 3, "better result")
+    manager:add_entry(nil, 3, "better result", "")
-    manager:add_entry(nil, 2, "better result")
+    manager:add_entry(nil, 2, "better result", "")
 
     -- Loops once to find 3 < 4
     -- Loops again to find 2 < 3
@@ -117,9 +118,9 @@ describe("process_result", function()
   it("should not loop a bunch, part 2", function()
     local info = {}
     local manager = EntryManager:new(5, nil, info)
-    manager:add_entry(nil, 4, "better result")
+    manager:add_entry(nil, 4, "better result", "")
-    manager:add_entry(nil, 2, "better result")
+    manager:add_entry(nil, 2, "better result", "")
-    manager:add_entry(nil, 3, "better result")
+    manager:add_entry(nil, 3, "better result", "")
 
     -- Loops again to find 2 < 4
     -- Loops once to find 3 > 2
@@ -129,9 +130,9 @@ describe("process_result", function()
 
   it("should update worst score in all append case", function()
     local manager = EntryManager:new(2, nil)
-    manager:add_entry(nil, 2, "result 2")
+    manager:add_entry(nil, 2, "result 2", "")
-    manager:add_entry(nil, 3, "result 3")
+    manager:add_entry(nil, 3, "result 3", "")
-    manager:add_entry(nil, 4, "result 4")
+    manager:add_entry(nil, 4, "result 4", "")
 
     eq(3, manager.worst_acceptable_score)
   end)
@@ -141,9 +142,9 @@ describe("process_result", function()
     local manager = EntryManager:new(2, function()
       called_count = called_count + 1
     end)
-    manager:add_entry(nil, 5, "worse result")
+    manager:add_entry(nil, 5, "worse result", "")
-    manager:add_entry(nil, 4, "less worse result")
+    manager:add_entry(nil, 4, "less worse result", "")
-    manager:add_entry(nil, 2, "better result")
+    manager:add_entry(nil, 2, "better result", "")
 
     -- Once for insert 5
     -- Once for prepend 4
@@ -153,4 +154,36 @@ describe("process_result", function()
     eq("better result", manager:get_entry(1))
     eq(4, manager.worst_acceptable_score)
   end)
+
+  it("should call tiebreaker if score is the same, sort length", function()
+    local manager = EntryManager:new(5, nil)
+    local picker = {
+      tiebreak = function(curr, prev, prompt)
+        eq("asdf", prompt)
+        return #curr < #prev
+      end,
+    }
+
+    manager:add_entry(picker, 0.5, "same same", "asdf")
+    manager:add_entry(picker, 0.5, "same", "asdf")
+
+    eq("same", manager:get_entry(1))
+    eq("same same", manager:get_entry(2))
+  end)
+
+  it("should call tiebreaker if score is the same, keep initial", function()
+    local manager = EntryManager:new(5, nil)
+    local picker = {
+      tiebreak = function(_, _, prompt)
+        eq("asdf", prompt)
+        return false
+      end,
+    }
+
+    manager:add_entry(picker, 0.5, "same same", "asdf")
+    manager:add_entry(picker, 0.5, "same", "asdf")
+
+    eq("same", manager:get_entry(2))
+    eq("same same", manager:get_entry(1))
+  end)
 end)