feat(lsp): vim.lsp.inlay_hint.enable(nil) applies to all buffers #28543

Problem:
Inlay hints `enable()` does not fully implement the `:help dev-lua` guidelines:

    Interface conventions ~
    - When accepting a buffer id, etc., 0 means "current buffer", nil means "all
      buffers".  Likewise for window id, tabpage id, etc.
      - Examples: |vim.lsp.codelens.clear()| |vim.diagnostic.enable()|

Solution:
Implement globally enabling inlay hints.
* refactor(lsp): do not rely on `enable` to create autocmds
* refactor(lsp): make `bufstates` a defaulttable
* refactor(lsp): make `bufstate` inherit values from `globalstate`
* feat(lsp): `vim.lsp.inlay_hints` now take effect on all buffers by default
* test(lsp): add basic tests for enable inlay hints for all buffers
* test(lsp): add test cases cover more than one buffer

1 files changed, 42 insertions, 11 deletions

diff --git a/test/functional/plugin/lsp/inlay_hint_spec.lua b/test/functional/plugin/lsp/inlay_hint_spec.lua
index 0aaf94d6da..94e7fbb97c 100644
--- a/test/functional/plugin/lsp/inlay_hint_spec.lua
+++ b/test/functional/plugin/lsp/inlay_hint_spec.lua
@@ -137,20 +137,51 @@ describe('vim.lsp.inlay_hint', function()
       )
     end)
 
-    it('clears/applies inlay hints when passed false/true/nil', function()
-      exec_lua([[vim.lsp.inlay_hint.enable(false, { bufnr = bufnr })]])
-      screen:expect({ grid = grid_without_inlay_hints, unchanged = true })
+    describe('clears/applies inlay hints when passed false/true/nil', function()
+      before_each(function()
+        exec_lua([[
+          bufnr2 = vim.api.nvim_create_buf(true, false)
+          vim.lsp.buf_attach_client(bufnr2, client_id)
+          vim.api.nvim_win_set_buf(0, bufnr2)
+        ]])
+        insert(text)
+        exec_lua([[vim.lsp.inlay_hint.enable(true, { bufnr = bufnr2 })]])
+        exec_lua([[vim.api.nvim_win_set_buf(0, bufnr)]])
+        screen:expect({ grid = grid_with_inlay_hints })
+      end)
 
-      exec_lua([[vim.lsp.inlay_hint.enable(true, { bufnr = bufnr })]])
-      screen:expect({ grid = grid_with_inlay_hints, unchanged = true })
+      it('for one single buffer', function()
+        exec_lua([[
+          vim.lsp.inlay_hint.enable(false, { bufnr = bufnr })
+          vim.api.nvim_win_set_buf(0, bufnr2)
+        ]])
+        screen:expect({ grid = grid_with_inlay_hints, unchanged = true })
+        exec_lua([[vim.api.nvim_win_set_buf(0, bufnr)]])
+        screen:expect({ grid = grid_without_inlay_hints, unchanged = true })
 
-      exec_lua(
-        [[vim.lsp.inlay_hint.enable(not vim.lsp.inlay_hint.is_enabled(bufnr), { bufnr = bufnr })]]
-      )
-      screen:expect({ grid = grid_without_inlay_hints, unchanged = true })
+        exec_lua([[vim.lsp.inlay_hint.enable(true, { bufnr = bufnr })]])
+        screen:expect({ grid = grid_with_inlay_hints, unchanged = true })
+
+        exec_lua(
+          [[vim.lsp.inlay_hint.enable(not vim.lsp.inlay_hint.is_enabled(bufnr), { bufnr = bufnr })]]
+        )
+        screen:expect({ grid = grid_without_inlay_hints, unchanged = true })
+
+        exec_lua([[vim.lsp.inlay_hint.enable(true, { bufnr = bufnr })]])
+        screen:expect({ grid = grid_with_inlay_hints, unchanged = true })
+      end)
+
+      it('for all buffers', function()
+        exec_lua([[vim.lsp.inlay_hint.enable(false)]])
+        screen:expect({ grid = grid_without_inlay_hints, unchanged = true })
+        exec_lua([[vim.api.nvim_win_set_buf(0, bufnr2)]])
+        screen:expect({ grid = grid_without_inlay_hints, unchanged = true })
 
-      exec_lua([[vim.lsp.inlay_hint.enable(true, { bufnr = bufnr })]])
-      screen:expect({ grid = grid_with_inlay_hints, unchanged = true })
+        exec_lua([[vim.lsp.inlay_hint.enable(true)]])
+        screen:expect({ grid = grid_with_inlay_hints, unchanged = true })
+        exec_lua([[vim.api.nvim_win_set_buf(0, bufnr)]])
+        screen:expect({ grid = grid_with_inlay_hints, unchanged = true })
+      end)
     end)
   end)