fix: normalizing a relative path returns an absolute path (#251)

* path: fix for normalizing files including ...

This still doesn't work for paths containing both .. parts as well as
...

* Use path.sep instead of hard coded /

* Change tests to check relative paths

* Add check for absolute path

* Linting fixes

* Update _normalize_path to check initial .. parts

This should return an absolute path if the initial .. count matches the
number of parts in the cwd (Path:_cwd)

Author: itmecho

lua/plenary/path.lua

@@ -76,29 +76,50 @@ local is_uri = function(filename)
   return string.match(filename, "^%w+://") ~= nil
 end
 
-local function _normalize_path(filename)
+local is_absolute = function(filename, sep)
+  if sep == "\\" then
+    return string.match(filename, "^[A-Z]:\\.*$")
+  end
+  return string.sub(filename, 1, 1) == sep
+end
+
+local function _normalize_path(filename, cwd)
   if is_uri(filename) then
     return filename
   end
 
   local out_file = filename
 
-  local has = string.find(filename, "..", 1, true)
+  local has = string.find(filename, path.sep .. "..", 1, true) or string.find(filename, ".." .. path.sep, 1, true)
 
   if has then
     local parts = _split_by_separator(filename)
 
     local idx = 1
+    local initial_up_count = 0
+
     repeat
       if parts[idx] == ".." then
+        if idx == 1 then
+          initial_up_count = initial_up_count + 1
+        end
         table.remove(parts, idx)
         table.remove(parts, idx - 1)
-        idx = idx - 2
+        if idx > 1 then
+          idx = idx - 2
+        else
+          idx = idx - 1
+        end
       end
       idx = idx + 1
     until idx > #parts
 
-    out_file = path.root(filename) .. table.concat(parts, path.sep)
+    local prefix = ""
+    if is_absolute(filename, path.sep) or #_split_by_separator(cwd) == initial_up_count then
+      prefix = path.root(filename)
+    end
+
+    out_file = prefix .. table.concat(parts, path.sep)
   end
 
   return out_file
@@ -251,9 +272,9 @@ end
 
 function Path:absolute()
   if self:is_absolute() then
-    return _normalize_path(self.filename)
+    return _normalize_path(self.filename, self._cwd)
   else
-    return _normalize_path(self._absolute or table.concat({ self._cwd, self.filename }, self._sep))
+    return _normalize_path(self._absolute or table.concat({ self._cwd, self.filename }, self._sep), self._cwd)
   end
 end
 
@@ -321,7 +342,7 @@ function Path:normalize(cwd)
   -- Substitute home directory w/ "~"
   self.filename = self.filename:gsub("^" .. path.home, "~", 1)
 
-  return _normalize_path(self.filename)
+  return _normalize_path(self.filename, self._cwd)
 end
 
 local function shorten_len(filename, len)
@@ -532,10 +553,7 @@ function Path:is_dir()
 end
 
 function Path:is_absolute()
-  if self._sep == "\\" then
-    return string.match(self.filename, "^[A-Z]:\\.*$")
-  end
-  return string.sub(self.filename, 1, 1) == self._sep
+  return is_absolute(self.filename, self._sep)
 end
 -- }}}
 

tests/plenary/path_spec.lua

@@ -185,6 +185,26 @@ describe("Path", function()
       local final = Path:new(orig):normalize()
       assert.are.same(final, "/lua/plenary/path.lua")
     end)
+
+    it("can normalize relative paths", function()
+      assert.are.same(Path:new("lua/plenary/path.lua"):normalize(), "lua/plenary/path.lua")
+    end)
+
+    it("can normalize relative paths containing ..", function()
+      assert.are.same(Path:new("lua/plenary/path.lua/../path.lua"):normalize(), "lua/plenary/path.lua")
+    end)
+
+    it("can normalize relative paths with initial ..", function()
+      local p = Path:new "../lua/plenary/path.lua"
+      p._cwd = "/tmp/lua"
+      assert.are.same("lua/plenary/path.lua", p:normalize())
+    end)
+
+    it("can normalize relative paths to absolute when initial .. count matches cwd parts", function()
+      local p = Path:new "../../tmp/lua/plenary/path.lua"
+      p._cwd = "/tmp/lua"
+      assert.are.same("/tmp/lua/plenary/path.lua", p:normalize())
+    end)
   end)
 
   describe(":shorten", function()