Rename does not work properly with ppx_string

[ddickstein]

I have a file that ends with the following:

let f x =
  [%string
    "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa \
     %{x}"]
;;

This is the zero-indexed line-range 241-245. Renaming x to y produces:

let f y =
  [%string
    y]
;;

The debug log of the messages is:

[DEBUG][2023-09-05 17:34:12] .../lua/vim/lsp.lua:1392	"LSP[ocaml-lsp]"	"client.request"	1	"textDocument/prepareRename"
{
  position = {
    character = 6,
    line = 241
  },
  textDocument = {
    uri = "file:///path/to/file.ml"
  }
}
[DEBUG][2023-09-05 17:34:12] .../vim/lsp/rpc.lua:284	"rpc.send"
{
  id = 6,
  jsonrpc = "2.0",
  method = "textDocument/prepareRename",
  params = {
    position = {
      character = 6,
      line = 241
    },
    textDocument = {
      uri = "file:///path/to/file.ml"
    }
  }
}
[DEBUG][2023-09-05 17:34:12] .../vim/lsp/rpc.lua:387	"rpc.receive"
{
  id = 6,
  jsonrpc = "2.0",
  result = {
    ["end"] = {
      character = 7,
      line = 241
    },
    start = {
      character = 6,
      line = 241
    }
  }
}
[DEBUG][2023-09-05 17:34:12] .../lua/vim/lsp.lua:1392	"LSP[ocaml-lsp]"	"client.request"	1	"textDocument/rename"
{
  newName = "y",
  position = {
    character = 6,
    line = 241
  },
  textDocument = {
    uri = "file:///path/to/file.ml"
  }
}
[DEBUG][2023-09-05 17:34:12] .../vim/lsp/rpc.lua:284	"rpc.send"
{
  id = 7,
  jsonrpc = "2.0",
  method = "textDocument/rename",
  params = {
    newName = "y",
    position = {
      character = 6,
      line = 241
    },
    textDocument = {
      uri = "file:///path/to/file.ml"
    }
  }
}
[DEBUG][2023-09-05 17:34:12] .../vim/lsp/rpc.lua:387	"rpc.receive"
{
  id = 7,
  jsonrpc = "2.0",
  result = {
    changes = {
      ["file:///path/to/file.ml"] = { {
          newText = "y",
          range = {
            ["end"] = {
              character = 7,
              line = 241
            },
            start = {
              character = 6,
              line = 241
            }
          }
        }, {
          newText = "y",
          range = {
            ["end"] = {
              character = 10,
              line = 244
            },
            start = {
              character = 4,
              line = 243
            }
          }
        } }
    }
  }
}

[rgrinberg]

Just to confirm, rename doesn't work properly with ppx_string in ocamllsp, but it does work in merlin. Is that correct?

[ddickstein]

Ah interesting this is definitely a Merlin bug (inspecting the debug output reveals this) but the :MerlinRename command in Vim does not actually perform the bad rename. The debug log says:

# 0.11 occurrences - Occurrences paths
[
  {
    "start": { "line": 242, "col": 6 },
    "end": { "line": 242, "col": 7 },
    "under_cursor": true,
    "path": "x"
  }
]
# 0.11 New_merlin - run(result)
{
  "class": "return",
  "value": [
    { "start": { "line": 242, "col": 6 }, "end": { "line": 242, "col": 7 } },
    { "start": { "line": 244, "col": 4 }, "end": { "line": 245, "col": 10 } }
  ],
  ...
}

but :MerlinRename y actually does:

let f y =
  [%string
    "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa \
     %{x}"]
;;

which is not ideal, but not bad behavior. But ocaml-lsp is more faithfully applying the Merlin edits than the Merlin vim plugin. I'll file a bug on Merlin.