server: implement rename (tougher!)

Heavily borrows code from jedi-language-server.

.gitignore

@@ -1,2 +1,2 @@
 __pycache__/
-
+*.egg-info/

README.md

@@ -6,17 +6,18 @@ Minimal Python language server, based on [Jedi][jedi] and [pygls][pygls].
 [jedi]: https://jedi.readthedocs.io/en/latest/index.html
 [pygls]: https://pygls.readthedocs.io/en/latest/index.html
 
-WIP! ⚠ 👷🚧
+Still in development but works on my machine. ✨
 
 Supported features:
 
 | LSP method                    | Description                |
-|-------------------------------|-----------------------|
+|-------------------------------|----------------------------|
 | `textDocument/completion`     | Complete                   |
 | `textDocument/definition`     | Go to definition           |
 | `textDocument/typeDefinition` | Go to type definition      |
 | `textDocument/hover`          | Show documentation         |
 | `textDocument/references`     | Show references            |
+| `textDocument/rename`         | Renaming symbols and files |
 
 
 
@@ -32,19 +33,21 @@ About
 
 ### Why?
 
-General-purpose servers (pyls, py-lsp) try to do too much and break stuff too
+General-purpose servers (e.g. pyls, py-lsp) try to do too much and break stuff
-often for me. Locking Neovim when I press tab, crashes of all kind, LspRestart
+too often for me. Locking Neovim when I press tab, crashes of all kind,
-failing. Also I like my linting and formatting done by dedicated tools such as
+LspRestart failing. Also I like my linting and formatting done by dedicated
-[nvim-lint][nvim-lint] and [formatter][formatter].
+tools such as [nvim-lint][nvim-lint] and [formatter][formatter].
 
 [nvim-lint]: https://github.com/mfussenegger/nvim-lint
 [formatter]: https://github.com/mhartington/formatter.nvim
 
-Other Jedi-based servers seem to focus on coc-nvim and frequently fail on
+Other Jedi-based servers (e.g. jedi-language-server) seem to focus on coc-nvim
-Neovim's native LSP client for me. I tried to fix jedi-language-server several
+and frequently fail on Neovim's native LSP client for me. I tried to fix
-times when it failed me but thought it could be fun to try pygls to redo it as
+jedi-language-server several times when it failed me but I thought it could be
-small and simple as I can. And running a Node server to get Python completions?
+fun to try pygls to redo it as small and simple as I can. And running a Node
-HA!
+server to get Python completions? No way. That said, jedi-language-server is a
+good project and if you're fine with coc-nvim you should definitely check it
+out. Lots of the code here is ~~stolen~~ inspired from this project.
 
 ### Why the name?
 

italianswirls/__main__.py

@@ -0,0 +1,8 @@
+from italianswirls.server import LS
+
+if __name__ == "__main__":
+    import logging
+    root_logger = logging.getLogger()
+    root_logger.setLevel(logging.DEBUG)
+    root_logger.addHandler(logging.FileHandler("/tmp/a.log"))
+    LS.start_io()

italianswirls/glue.py

@@ -0,0 +1,157 @@
+"""Glue between Jedi and LSP data structures."""
+
+import bisect
+import difflib
+from typing import Generator, Optional, Union
+
+from jedi.api.classes import Name
+from jedi.api.refactoring import Refactoring
+from pygls.lsp.types import (CompletionItemKind, Location, Position, Range,
+                             RenameFile, RenameFileOptions,
+                             ResourceOperationKind, TextDocumentEdit, TextEdit,
+                             VersionedTextDocumentIdentifier)
+from pygls.workspace import Workspace
+
+JEDI_COMPLETION_TYPE_MAP = {
+    "module": CompletionItemKind.Module,
+    "class": CompletionItemKind.Class,
+    "instance": CompletionItemKind.Variable,
+    "function": CompletionItemKind.Function,
+    "param": CompletionItemKind.Variable,
+    "path": CompletionItemKind.File,
+    "keyword": CompletionItemKind.Keyword,
+    "property": CompletionItemKind.Property,
+    "statement": CompletionItemKind.Variable,
+}
+
+
+def get_jedi_position(position: Position) -> tuple[int, int]:
+    """Translate LSP Position to Jedi position (where line is 1-based)."""
+    return position.line + 1, position.character
+
+
+def get_lsp_position(line: int, column: int) -> Position:
+    """Translate Jedi position to LSP Position (where line is 0-based)."""
+    return Position(line=line - 1, character=column)
+
+
+def get_lsp_range(name: Name) -> Optional[Range]:
+    """Get an LSP range for this name, if it has a location."""
+    if name.line is None or name.column is None:
+        return None
+    start_position = get_lsp_position(name.line, name.column)
+    end_position = get_lsp_position(name.line, name.column + len(name.name))
+    return Range(start=start_position, end=end_position)
+
+
+def get_lsp_location(name: Name) -> Optional[Location]:
+    """Return an LSP location from this Jedi Name."""
+    if name.module_path is None:
+        return None
+    if (lsp_range := get_lsp_range(name)) is None:
+        return None
+    return Location(uri=name.module_path.as_uri(), range=lsp_range)
+
+
+def get_lsp_locations(names: list[Name]) -> list[Location]:
+    """Return a list of LSP locations from this list of Jedi Names.
+
+    Names that cannot be converted to a LSP location are discarded.
+    """
+    lsp_locations = []
+    for name in names:
+        if lsp_location := get_lsp_location(name):
+            lsp_locations.append(lsp_location)
+    return lsp_locations
+
+
+def get_lsp_completion_kind(jedi_compl_type: str) -> CompletionItemKind:
+    """Return an LSP completion item kind from this Jedi completion type."""
+    return JEDI_COMPLETION_TYPE_MAP.get(
+        jedi_compl_type,
+        CompletionItemKind.Text
+    )
+
+
+def _build_line_offsets(text: str) -> list[int]:
+    """Return a list of indexes where each line of the text starts."""
+    line_offsets = []
+    offset = 0
+    for line in text.splitlines(keepends=True):
+        line_offsets.append(offset)
+        offset += len(line)
+    return line_offsets
+
+
+def _get_lsp_position_from_offsets(
+    line_offsets: list[int],
+    offset: int,
+) -> Position:
+    """Return an LSP Position for this offset, using these line offsets."""
+    line_number = bisect.bisect_right(line_offsets, offset) - 1
+    character_number = offset - line_offsets[line_number]
+    return Position(line=line_number, character=character_number)
+
+
+def gen_document_edits(
+    refactoring: Refactoring,
+    workspace: Workspace,
+) -> Generator[Union[TextDocumentEdit, RenameFile], None, None]:
+    """Generate TextDocumentEdit and RenameFile objects from a refactoring."""
+    yield from _gen_document_text_edits(refactoring, workspace)
+    yield from _gen_document_renames(refactoring, workspace)
+
+
+def _gen_document_text_edits(
+    refactoring: Refactoring,
+    workspace: Workspace,
+) -> Generator[TextDocumentEdit, None, None]:
+    """Generate TextDocumentEdit objects for each text modification.
+
+    Compare previous code and refactored code using standard difflib. The main
+    complexity here is to translate difflib's opcode positions into LSP ranges.
+    This code is 99% taken from the neat jedi-language-server implementation.
+    """
+    for path, changed_file in refactoring.get_changed_files().items():
+        document_uri = path.as_uri()
+        document = workspace.get_document(document_uri)
+        old_code = document.source
+        new_code = changed_file.get_new_code()
+        line_offsets = _build_line_offsets(old_code)
+        edit_operations = (
+            opcode for opcode in
+            difflib.SequenceMatcher(a=old_code, b=new_code).get_opcodes()
+            if opcode[0] != "equal"
+        )
+        text_edits: list[TextEdit] = []
+        for op, old_start, old_end, new_start, new_end in edit_operations:
+            new_text = new_code[new_start:new_end]
+            start_pos = _get_lsp_position_from_offsets(line_offsets, old_start)
+            end_pos = _get_lsp_position_from_offsets(line_offsets, old_end)
+            edit_range = Range(start=start_pos, end=end_pos)
+            text_edits.append(TextEdit(range=edit_range, new_text=new_text))
+        if not text_edits:
+            continue
+
+        document_id = VersionedTextDocumentIdentifier(
+            uri=document_uri,
+            version=document.version or 0,
+        )
+        yield TextDocumentEdit(
+            text_document=document_id,
+            edits=text_edits,
+        )
+
+
+def _gen_document_renames(
+    refactoring: Refactoring,
+    workspace: Workspace,
+) -> Generator[RenameFile, None, None]:
+    """Generate RenameFile objects for each renamed file."""
+    for old_name, new_name in refactoring.get_renames():
+        yield RenameFile(
+            kind=ResourceOperationKind.Rename,
+            old_uri=old_name.as_uri(),
+            new_uri=new_name.as_uri(),
+            options=RenameFileOptions(ignore_if_exists=True, overwrite=True)
+        )

italianswirls/server.py

@@ -2,36 +2,23 @@ import logging
 from typing import Optional
 
 from jedi import Script
-from jedi.api.classes import Name
+from jedi.api.refactoring import RefactoringError
 from pygls.lsp.methods import (COMPLETION, DEFINITION, HOVER, REFERENCES,
-                               TYPE_DEFINITION)
+                               RENAME, TYPE_DEFINITION)
-from pygls.lsp.types import (CompletionItem, CompletionItemKind,
+from pygls.lsp.types import (CompletionItem, CompletionList, CompletionOptions,
-                             CompletionList, CompletionOptions,
                              CompletionParams, DefinitionParams, Hover,
-                             HoverParams, InsertTextFormat,
+                             HoverParams, InsertTextFormat, Location,
-                             Location, Position, Range, ReferenceParams,
+                             ReferenceParams, RenameParams,
-                             TextDocumentPositionParams, TypeDefinitionParams)
+                             TextDocumentPositionParams, TypeDefinitionParams,
+                             WorkspaceEdit)
 from pygls.server import LanguageServer
 from pygls.workspace import Document
 
-LOG = logging.getLogger()
+from italianswirls.glue import (gen_document_edits, get_jedi_position,
-LOG.setLevel(logging.DEBUG)
+                                get_lsp_completion_kind, get_lsp_locations)
-LOG.addHandler(logging.FileHandler("/tmp/a.log"))
 
 LS = LanguageServer('italianswirls', 'v0.0.1')
 
-JEDI_COMPLETION_TYPE_MAP = {
-    "module": CompletionItemKind.Module,
-    "class": CompletionItemKind.Class,
-    "instance": CompletionItemKind.Variable,
-    "function": CompletionItemKind.Function,
-    "param": CompletionItemKind.Variable,
-    "path": CompletionItemKind.File,
-    "keyword": CompletionItemKind.Keyword,
-    "property": CompletionItemKind.Property,
-    "statement": CompletionItemKind.Variable,
-}
-
 
 def get_jedi_script(document: Document) -> Script:
     """Get Jedi Script object from this document."""
@@ -49,54 +36,6 @@ def get_jedi_script_from_params(
     return script
 
 
-def get_jedi_position(position: Position) -> tuple[int, int]:
-    """Translate LSP Position to Jedi position (where line is 1-based)."""
-    return position.line + 1, position.character
-
-
-def get_lsp_position(line: int, column: int) -> Position:
-    """Translate Jedi position to LSP Position (where line is 0-based)."""
-    return Position(line=line - 1, character=column)
-
-
-def get_lsp_range(name: Name) -> Optional[Range]:
-    """Get an LSP range for this name, if it has a location."""
-    if name.line is None or name.column is None:
-        return None
-    start_position = get_lsp_position(name.line, name.column)
-    end_position = get_lsp_position(name.line, name.column + len(name.name))
-    return Range(start=start_position, end=end_position)
-
-
-def get_lsp_location(name: Name) -> Optional[Location]:
-    """Return an LSP location from this Jedi Name."""
-    if name.module_path is None:
-        return None
-    if (lsp_range := get_lsp_range(name)) is None:
-        return None
-    return Location(uri=name.module_path.as_uri(), range=lsp_range)
-
-
-def get_lsp_locations(names: list[Name]) -> list[Location]:
-    """Return a list of LSP locations from this list of Jedi Names.
-
-    Names that cannot be converted to a LSP location are discarded.
-    """
-    lsp_locations = []
-    for name in names:
-        if lsp_location := get_lsp_location(name):
-            lsp_locations.append(lsp_location)
-    return lsp_locations
-
-
-def get_lsp_completion_kind(jedi_compl_type: str) -> CompletionItemKind:
-    """Return an LSP completion item kind from this Jedi completion type."""
-    return JEDI_COMPLETION_TYPE_MAP.get(
-        jedi_compl_type,
-        CompletionItemKind.Text
-    )
-
-
 @LS.feature(COMPLETION, CompletionOptions(trigger_characters=["."]))
 async def do_completion(
     server: LanguageServer,
@@ -203,5 +142,20 @@ async def do_hover(
     return Hover(contents=hover_text)
 
 
-if __name__ == "__main__":
+@LS.feature(RENAME)
-    LS.start_io()
+async def do_rename(
+    server: LanguageServer,
+    params: RenameParams,
+) -> Optional[WorkspaceEdit]:
+    """Ask Jedi to rename a symbol and return the resulting state."""
+    script = get_jedi_script_from_params(params, server)
+    jedi_position = get_jedi_position(params.position)
+    try:
+        refactoring = script.rename(*jedi_position, new_name=params.new_name)
+    except RefactoringError as exc:
+        logging.error(f"Refactoring failed: {exc}")
+        return None
+
+    changes = list(gen_document_edits(refactoring, server.workspace))
+    logging.info(f"changes: {changes}")
+    return WorkspaceEdit(document_changes=changes) if changes else None

mypy.ini

@@ -0,0 +1,6 @@
+[mypy]
+warn_return_any = True
+warn_unused_configs = True
+
+zsh:1: command not found: a
+ignore_missing_imports = True

pyproject.toml

@@ -0,0 +1,3 @@
+[build-system]
+requires = ["setuptools", "wheel"]
+build-backend = "setuptools.build_meta"