The most notable change of the v1.0
release of pygls
is the removal of its hand written LSP type and method definitions in favour of relying on the types provided by the lsprotocol library which are automatically generated from the LSP specification. As as side effect this has also meant the removal of pydantic as a dependency, since lsprotocol
uses attrs and cattrs for serialisation and validation.
This guide outlines how to adapt an existing server to the breaking changes introduced in this release.
You may find insight and inspiration from these projects that have already successfully migrated to v1:
The pygls.lsp.methods
and pygls.lsp.types
modules no longer exist. Instead, all types and method names should now be imported from the lsprotocol.types
module.
Additionally, the following types and constants have been renamed.
pygls | lsprotocol |
---|---|
CODE_ACTION |
TEXT_DOCUMENT_CODE_ACTION |
CODE_LENS |
TEXT_DOCUMENT_CODE_LENS |
COLOR_PRESENTATION |
TEXT_DOCUMENT_COLOR_PRESENTATION |
COMPLETION |
TEXT_DOCUMENT_COMPLETION |
DECLARATION |
TEXT_DOCUMENT_DECLARATION |
DEFINITION |
TEXT_DOCUMENT_DEFINITION |
DOCUMENT_COLOR |
TEXT_DOCUMENT_DOCUMENT_COLOR |
DOCUMENT_HIGHLIGHT |
TEXT_DOCUMENT_DOCUMENT_HIGHLIGHT |
DOCUMENT_LINK |
TEXT_DOCUMENT_DOCUMENT_LINK |
DOCUMENT_SYMBOL |
TEXT_DOCUMENT_DOCUMENT_SYMBOL |
FOLDING_RANGE |
TEXT_DOCUMENT_FOLDING_RANGE |
FORMATTING |
TEXT_DOCUMENT_FORMATTING |
HOVER |
TEXT_DOCUMENT_HOVER |
IMPLEMENTATION |
TEXT_DOCUMENT_IMPLEMENTATION |
LOG_TRACE_NOTIFICATION |
LOG_TRACE |
ON_TYPE_FORMATTING |
TEXT_DOCUMENT_ON_TYPE_FORMATTING |
PREPARE_RENAME |
TEXT_DOCUMENT_PREPARE_RENAME |
PROGRESS_NOTIFICATION |
PROGRESS |
RANGE_FORMATTING |
TEXT_DOCUMENT_RANGE_FORMATTING |
REFERENCES |
TEXT_DOCUMENT_REFERENCES |
RENAME |
TEXT_DOCUMENT_RENAME |
SELECTION_RANGE |
TEXT_DOCUMENT_SELECTION_RANGE |
SET_TRACE_NOTIFICATION |
SET_TRACE |
SIGNATURE_HELP |
TEXT_DOCUMENT_SIGNATURE_HELP |
TEXT_DOCUMENT_CALL_HIERARCHY_INCOMING_CALLS |
CALL_HIERARCHY_INCOMING_CALLS |
TEXT_DOCUMENT_CALL_HIERARCHY_OUTGOING_CALLS |
CALL_HIERARCHY_OUTGOING_CALLS |
TEXT_DOCUMENT_CALL_HIERARCHY_PREPARE |
TEXT_DOCUMENT_PREPARE_CALL_HIERARCHY |
TYPE_DEFINITION |
TEXT_DOCUMENT_TYPE_DEFINITION |
WORKSPACE_FOLDERS |
WORKSPACE_WORKSPACE_FOLDERS |
ApplyWorkspaceEditResponse |
ApplyWorkspaceEditResult |
ClientInfo |
InitializeParamsClientInfoType |
CodeActionDisabled |
CodeActionDisabledType |
CodeActionLiteralSupportActionKindClientCapabilities |
CodeActionClientCapabilitiesCodeActionLiteralSupportTypeCodeActionKindType |
CodeActionLiteralSupportClientCapabilities |
CodeActionClientCapabilitiesCodeActionLiteralSupportType |
CompletionItemClientCapabilities |
CompletionClientCapabilitiesCompletionItemType |
CompletionItemKindClientCapabilities |
CompletionClientCapabilitiesCompletionItemKindType |
CompletionTagSupportClientCapabilities |
CompletionClientCapabilitiesCompletionItemTypeTagSupportType |
DocumentSymbolCapabilitiesTagSupport |
DocumentSymbolClientCapabilitiesTagSupportType |
InsertTextModeSupportClientCapabilities |
CompletionClientCapabilitiesCompletionItemTypeInsertTextModeSupportType |
MarkedStringType |
MarkedString |
MarkedString |
MarkedString_Type1 |
PrepareRename |
PrepareRenameResult_Type1 |
PublishDiagnosticsTagSupportClientCapabilities |
PublishDiagnosticsClientCapabilitiesTagSupportType |
ResolveSupportClientCapabilities |
CodeActionClientCapabilitiesResolveSupportType |
SemanticTokensRequestsFull |
SemanticTokensRegistrationOptionsFullType1 |
SemanticTokensRequests |
SemanticTokensClientCapabilitiesRequestsType |
ServerInfo |
InitializeResultServerInfoType |
ShowMessageRequestActionItem |
ShowMessageRequestClientCapabilitiesMessageActionItemType |
SignatureHelpInformationClientCapabilities |
SignatureHelpClientCapabilitiesSignatureInformationType |
SignatureHelpInformationParameterInformationClientCapabilities |
SignatureHelpClientCapabilitiesSignatureInformationTypeParameterInformationType |
TextDocumentContentChangeEvent |
TextDocumentContentChangeEvent_Type1 |
TextDocumentContentChangeTextEvent |
TextDocumentContentChangeEvent_Type2 |
TextDocumentSyncOptionsServerCapabilities |
TextDocumentSyncOptions |
Trace |
TraceValues |
URI |
str |
WorkspaceCapabilitiesSymbolKind |
WorkspaceSymbolClientCapabilitiesSymbolKindType |
WorkspaceCapabilitiesTagSupport |
WorkspaceSymbolClientCapabilitiesTagSupportType |
WorkspaceFileOperationsServerCapabilities |
FileOperationOptions |
WorkspaceServerCapabilities |
ServerCapabilitiesWorkspaceType |
One of the most obvious changes is the switch to attrs and cattrs for serialization and deserialisation. This means that any custom models used by your language server will need to be converted to an attrs
style class.
# Before
from pydantic import BaseModel, Field
class ExampleConfig(BaseModel):
build_dir: Optional[str] = Field(None, alias="buildDir")
builder_name: str = Field("html", alias="builderName")
conf_dir: Optional[str] = Field(None, alias="confDir")
# After
import attrs
@attrs.define
class ExampleConfig:
build_dir: Optional[str] = attrs.field(default=None)
builder_name: str = attrs.field(default="html")
conf_dir: Optional[str] = attrs.field(default=None)
Pygls provides a default converter that it will use when converting your models to/from JSON, which should be sufficient for most scenarios.
>>> from pygls.protocol import default_converter
>>> converter = default_converter()
>>> config = ExampleConfig(builder_name='epub', conf_dir='/path/to/conf')
>>> converter.unstructure(config)
{'builderName': 'epub', 'confDir': '/path/to/conf'} # Note how snake_case is converted to camelCase
>>> converter.structure({'builderName': 'epub', 'confDir': '/path/to/conf'}, ExampleConfig)
ExampleConfig(build_dir=None, builder_name='epub', conf_dir='/path/to/conf')
However, depending on the complexity of your type definitions you may find the default converter fail to parse some of your types.
>>> from typing import Literal, Union
>>> @attrs.define
... class ExampleConfig:
... num_jobs: Union[Literal["auto"], int] = attrs.field(default='auto')
...
>>> converter.structure({'numJobs': 'auto'}, ExampleConfig)
+ Exception Group Traceback (most recent call last):
| File "<stdin>", line 1, in <module>
| File "/.../python3.10/site-packages/cattrs/converters.py", li
ne 309, in structure
| return self._structure_func.dispatch(cl)(obj, cl)
| File "<cattrs generated structure __main__.ExampleConfig-2>", line 10, in structure_ExampleConfig
| if errors: raise __c_cve('While structuring ' + 'ExampleConfig', errors, __cl)
| cattrs.errors.ClassValidationError: While structuring ExampleConfig (1 sub-exception)
+-+---------------- 1 ----------------
| Traceback (most recent call last):
| File "<cattrs generated structure __main__.ExampleConfig-2>", line 6, in structure_ExampleConfig
| res['num_jobs'] = __c_structure_num_jobs(o['numJobs'], __c_type_num_jobs)
| File "/.../python3.10/site-packages/cattrs/converters.py",
line 377, in _structure_error
| raise StructureHandlerNotFoundError(msg, type_=cl)
| cattrs.errors.StructureHandlerNotFoundError: Unsupported type: typing.Union[typing.Literal['auto'], int].
Register a structure hook for it.
| Structuring class ExampleConfig @ attribute num_jobs
+------------------------------------
In which case you can extend the converter provided by pygls
with your own structure hooks
from pygls.protocol import default_converter
def custom_converter():
converter = default_converter()
converter.register_structure_hook(Union[Literal['auto', int], lambda obj, _: obj)
return converter
You can then override the default converter used by pygls
when constructing your language server instance
server = LanguageServer(
name="my-language-server", version="v1.0", converter_factory=custom_converter
)
See the hooks.py module in lsprotocol
for some example structure hooks
It is now necessary to provide a name and version when constructing an instance of the LanguageServer
class
from pygls.server import LanguageServer
server = LanguageServer(name="my-language-server", version="v1.0")
# Before
from pygls.lsp.types import ClientCapabilities
client_capabilities = ClientCapabilities()
commit_character_support = client_capabilities.get_capability(
"text_document.completion.completion_item.commit_characters_support", False
)
# After
from lsprotocol.types import ClientCapabilities
from pygls.capabilities import get_capability
client_capabilities = ClientCapabilities()
commit_character_support = get_capability(
client_capabilities,
"text_document.completion.completion_item.commit_characters_support",
False
)