fix: make watchman scanner work with path argument

Although the wisdom of making heavy use of this functionality is dubious
(because as you add more watches to Watchman, the slower it gets,
especially in the case of nested projects under a shared root, if my
experience with running the benchmarks is anything to be believed).

data/wincent/commandt/benchmark/configs/scanner.lua

@@ -224,6 +224,19 @@ return {
       source = 'wincent.commandt.private.scanners.watchman',
       times = times,
       skip_in_ci = true,
+      stub_candidates = function()
+        assert(_G.vim == nil)
+        _G.vim = {
+          fn = {
+            fnamemodify = function(name, _modifier)
+              return name
+            end,
+          },
+        }
+      end,
+      unstub_candidates = function()
+        _G.vim = nil
+      end,
     },
   },
 }

lua/wincent/commandt/private/finders/watchman.lua

@@ -9,7 +9,6 @@ return function(directory, options)
   end
   local lib = require('wincent.commandt.private.lib')
   local finder = {}
-  -- TODO: make `directory` actually do something here
   finder.scanner = require('wincent.commandt.private.scanners.watchman').scanner(directory)
   finder.matcher = lib.matcher_new(finder.scanner, options)
   finder.run = function(query)

lua/wincent/commandt/private/scanners/watchman.lua

@@ -87,7 +87,7 @@ local result = nil
 
 watchman.scanner = function(directory)
   local lib = require('wincent.commandt.private.lib')
-  local project = watch_project(directory)
+  local project = watch_project(vim.fn.fnamemodify(directory, ':p'))
   if project.error then
     error(project.error)
     -- TODO: in the future (once Watchman is more solid), degrade gracefully