fix: correctly capture uri scheme on windows (#16027)

closes https://github.com/neovim/neovim/issues/15261

* normalize uri path to forward slashes on windows
* use a capture group on windows that avoids mistaking drive letters as uri scheme

2 files changed, 27 insertions, 1 deletions

diff --git a/runtime/lua/vim/uri.lua b/runtime/lua/vim/uri.lua
index a3e79a0f2b..5d8d4fa169 100644
--- a/runtime/lua/vim/uri.lua
+++ b/runtime/lua/vim/uri.lua
@@ -75,13 +75,22 @@ local function uri_from_fname(path)
 end
 
 local URI_SCHEME_PATTERN = '^([a-zA-Z]+[a-zA-Z0-9+-.]*):.*'
+local WINDOWS_URI_SCHEME_PATTERN = '^([a-zA-Z]+[a-zA-Z0-9+-.]*):[a-zA-Z]:.*'
 
 --- Get a URI from a bufnr
 ---@param bufnr (number): Buffer number
 ---@return URI
 local function uri_from_bufnr(bufnr)
   local fname = vim.api.nvim_buf_get_name(bufnr)
-  local scheme = fname:match(URI_SCHEME_PATTERN)
+  local volume_path = fname:match("^([a-zA-Z]:).*")
+  local is_windows = volume_path ~= nil
+  local scheme
+  if is_windows then
+    fname = fname:gsub("\\", "/")
+    scheme = fname:match(WINDOWS_URI_SCHEME_PATTERN)
+  else
+    scheme = fname:match(URI_SCHEME_PATTERN)
+  end
   if scheme then
     return fname
   else
diff --git a/test/functional/lua/uri_spec.lua b/test/functional/lua/uri_spec.lua
index 052a8a1ecd..81f1820986 100644
--- a/test/functional/lua/uri_spec.lua
+++ b/test/functional/lua/uri_spec.lua
@@ -2,6 +2,7 @@ local helpers = require('test.functional.helpers')(after_each)
 local clear = helpers.clear
 local exec_lua = helpers.exec_lua
 local eq = helpers.eq
+local write_file = require('test.helpers').write_file
 
 describe('URI methods', function()
   before_each(function()
@@ -158,6 +159,22 @@ describe('URI methods', function()
 
   end)
 
+  describe('uri from bufnr', function()
+    it('Windows paths should not be treated as uris', function()
+      if not helpers.iswin() then return end
+
+      local file = helpers.tmpname()
+      write_file(file, 'Test content')
+        local test_case = string.format([[
+          local file = '%s'
+          return vim.uri_from_bufnr(vim.fn.bufadd(file))
+        ]], file)
+        local expected_uri = 'file:///' .. file:gsub("\\", "/")
+        eq(expected_uri, exec_lua(test_case))
+        os.remove(file)
+    end)
+  end)
+
   describe('uri to bufnr', function()
     it('uri_to_bufnr & uri_from_bufnr returns original uri for non-file uris', function()
       local uri = 'jdt://contents/java.base/java.util/List.class?=sql/%5C/home%5C/user%5C/.jabba%5C/jdk%5C/openjdk%5C@1.14.0%5C/lib%5C/jrt-fs.jar%60java.base=/javadoc_location=/https:%5C/%5C/docs.oracle.com%5C/en%5C/java%5C/javase%5C/14%5C/docs%5C/api%5C/=/%3Cjava.util(List.class'