Allow customizing the LSP binary

src/multilspy/language_servers/clangd_language_server/clangd_language_server.py

@@ -57,6 +57,12 @@ def setup_runtime_dependencies(self, logger: MultilspyLogger, config: MultilspyC
             "osx-arm64",
         ], "Unsupported platform: " + platform_id.value
 
+        # Check for custom binary after platform validation
+        if config.custom_lsp_binary:
+            path = os.path.abspath(config.custom_lsp_binary)
+            assert os.path.exists(path)
+            return path
+
         runtime_dependencies = d["runtimeDependencies"]
         runtime_dependencies = [
             dependency for dependency in runtime_dependencies if dependency["platformId"] == platform_id.value

src/multilspy/language_servers/dart_language_server/dart_language_server.py

@@ -21,7 +21,7 @@ def __init__(self, config, logger, repository_root_path):
         Creates a DartServer instance. This class is not meant to be instantiated directly. Use LanguageServer.create() instead.
         """
 
-        executable_path = self.setup_runtime_dependencies(logger)
+        executable_path = self.setup_runtime_dependencies(logger, config)
         super().__init__(
             config,
             logger,
@@ -30,7 +30,20 @@ def __init__(self, config, logger, repository_root_path):
             "dart",
         )
 
-    def setup_runtime_dependencies(self, logger: "MultilspyLogger") -> str:
+    def setup_runtime_dependencies(self, logger: "MultilspyLogger", config: "MultilspyConfig") -> str:
+        lsp_args = [
+            "language-server",
+            "--client-id",
+            "multilspy.dart",
+            "--client-version",
+            "1.2",
+        ]
+        # Check for custom binary after platform validation
+        if config.custom_lsp_binary:
+            path = os.path.abspath(config.custom_lsp_binary)
+            assert os.path.exists(path)
+            return f"{path} {' '.join(lsp_args)}"
+
         platform_id = PlatformUtils.get_platform_id()
 
         with open(os.path.join(os.path.dirname(__file__), "runtime_dependencies.json"), "r") as f:
@@ -58,7 +71,7 @@ def setup_runtime_dependencies(self, logger: "MultilspyLogger") -> str:
         assert os.path.exists(dart_executable_path)
         os.chmod(dart_executable_path, stat.S_IEXEC)
 
-        return f"{dart_executable_path} language-server --client-id multilspy.dart --client-version 1.2"
+        return f"{dart_executable_path} {' '.join(lsp_args)}"
 
 
     def _get_initialize_params(self, repository_absolute_path: str):

src/multilspy/language_servers/eclipse_jdtls/eclipse_jdtls.py

@@ -51,7 +51,7 @@ def __init__(self, config: MultilspyConfig, logger: MultilspyLogger, repository_
         Creates a new EclipseJDTLS instance initializing the language server settings appropriately.
         This class is not meant to be instantiated directly. Use LanguageServer.create() instead.
         """
-
+        
         runtime_dependency_paths = self.setupRuntimeDependencies(logger, config)
         self.runtime_dependency_paths = runtime_dependency_paths
 
@@ -97,6 +97,14 @@ def __init__(self, config: MultilspyConfig, logger: MultilspyLogger, repository_
         # TODO: Add "self.runtime_dependency_paths.jre_home_path"/bin to $PATH as well
         proc_env = {"syntaxserver": "false", "JAVA_HOME": self.runtime_dependency_paths.jre_home_path}
         proc_cwd = repository_root_path
+
+        # Override JDTLS launcher jar path if custom "binary" is provided
+        launcher_jar = jdtls_launcher_jar
+        if config.custom_lsp_binary:
+            custom_path = os.path.abspath(config.custom_lsp_binary)
+            assert os.path.exists(custom_path)
+            launcher_jar = custom_path
+
         cmd = " ".join(
             [
                 jre_path,
@@ -125,7 +133,7 @@ def __init__(self, config: MultilspyConfig, logger: MultilspyLogger, repository_
                 f"-javaagent:{lombok_jar_path}",
                 f"-Djdt.core.sharedIndexLocation={shared_cache_location}",
                 "-jar",
-                jdtls_launcher_jar,
+                launcher_jar,
                 "-configuration",
                 jdtls_config_path,
                 "-data",

src/multilspy/language_servers/gopls/gopls.py

@@ -42,7 +42,7 @@ def _get_gopls_version():
         return None
 
     @classmethod
-    def setup_runtime_dependency(cls):
+    def setup_runtime_dependency(cls, config: MultilspyConfig):
         """
         Check if required Go runtime dependencies are available.
         Raises RuntimeError with helpful message if dependencies are missing.
@@ -53,6 +53,9 @@ def setup_runtime_dependency(cls):
         go_version = cls._get_go_version()
         if not go_version:
             missing_deps.append(("Go", "https://golang.org/doc/install"))
+
+        if config.custom_lsp_binary:
+            return True
 
         # Check for gopls
         gopls_version = cls._get_gopls_version()
@@ -69,13 +72,19 @@ def setup_runtime_dependency(cls):
 
     def __init__(self, config: MultilspyConfig, logger: MultilspyLogger, repository_root_path: str):
         # Check runtime dependencies before initializing
-        self.setup_runtime_dependency()
+        self.setup_runtime_dependency(config)
+
+        cmd = "gopls"
+        if config.custom_lsp_binary:
+            path = os.path.abspath(config.custom_lsp_binary)
+            assert os.path.exists(path)
+            cmd = path
 
         super().__init__(
             config,
             logger,
             repository_root_path,
-            ProcessLaunchInfo(cmd="gopls", cwd=repository_root_path),
+            ProcessLaunchInfo(cmd=cmd, cwd=repository_root_path),
             "go",
         )
         self.server_ready = asyncio.Event()

src/multilspy/language_servers/jedi_language_server/jedi_server.py

@@ -25,11 +25,17 @@ def __init__(self, config: MultilspyConfig, logger: MultilspyLogger, repository_
         """
         Creates a JediServer instance. This class is not meant to be instantiated directly. Use LanguageServer.create() instead.
         """
+        cmd = "jedi-language-server"
+        if config.custom_lsp_binary:
+            path = os.path.abspath(config.custom_lsp_binary)
+            assert os.path.exists(path)
+            cmd = path
+
         super().__init__(
             config,
             logger,
             repository_root_path,
-            ProcessLaunchInfo(cmd="jedi-language-server", cwd=repository_root_path),
+            ProcessLaunchInfo(cmd=cmd, cwd=repository_root_path),
             "python",
         )
 

src/multilspy/language_servers/kotlin_language_server/kotlin_language_server.py

@@ -124,6 +124,12 @@ def setup_runtime_dependencies(self, logger: MultilspyLogger, config: MultilspyC
         else:
             raise FileNotFoundError(f"Kotlin Language Server script not found at {kotlin_script}")
 
+        # Override executable path if custom binary is provided
+        if config.custom_lsp_binary:
+            custom_path = os.path.abspath(config.custom_lsp_binary)
+            assert os.path.exists(custom_path)
+            kotlin_executable_path = custom_path
+
         return KotlinRuntimeDependencyPaths(
             java_path=java_path,
             java_home_path=java_home_path,

src/multilspy/language_servers/omnisharp/omnisharp.py

@@ -197,6 +197,13 @@ def setupRuntimeDependencies(self, logger: MultilspyLogger, config: MultilspyCon
         )
         assert os.path.exists(razor_omnisharp_dll_path)
 
+        # Override executable path if custom binary is provided
+        # Note: Only the OmniSharp executable path is replaced.
+        if config.custom_lsp_binary:
+            custom_path = os.path.abspath(config.custom_lsp_binary)
+            assert os.path.exists(custom_path)
+            omnisharp_executable_path = custom_path
+
         return omnisharp_executable_path, razor_omnisharp_dll_path
 
     @asynccontextmanager

src/multilspy/language_servers/rust_analyzer/rust_analyzer.py

@@ -43,6 +43,12 @@ def setup_runtime_dependencies(self, logger: MultilspyLogger, config: MultilspyC
         """
         Setup runtime dependencies for rust_analyzer.
         """
+
+        if config.custom_lsp_binary:
+            path = os.path.abspath(config.custom_lsp_binary)
+            assert os.path.exists(path)
+            return path
+
         platform_id = PlatformUtils.get_platform_id()
 
         with open(os.path.join(os.path.dirname(__file__), "runtime_dependencies.json"), "r") as f:

src/multilspy/language_servers/solargraph/solargraph.py

@@ -47,6 +47,11 @@ def setup_runtime_dependencies(self, logger: MultilspyLogger, config: MultilspyC
         """
         Setup runtime dependencies for Solargraph.
         """
+        # Check for custom binary after Ruby validation
+        if config.custom_lsp_binary:
+            path = os.path.abspath(config.custom_lsp_binary)
+            assert os.path.exists(path)
+            return path
 
         with open(os.path.join(os.path.dirname(__file__), "runtime_dependencies.json"), "r") as f:
             d = json.load(f)

src/multilspy/language_servers/typescript_language_server/typescript_language_server.py

@@ -61,6 +61,15 @@ def setup_runtime_dependencies(self, logger: MultilspyLogger, config: MultilspyC
         ] 
         assert platform_id in valid_platforms, f"Platform {platform_id} is not supported for multilspy javascript/typescript at the moment"
 
+        # Check for custom binary after platform validation
+        # Note: The '--stdio' flag is automatically appended to the custom binary path,
+        # as it's required for LSP communication. Provide the path to the
+        # typescript-language-server executable.
+        if config.custom_lsp_binary:
+            path = os.path.abspath(config.custom_lsp_binary)
+            assert os.path.exists(path)
+            return f"{path} --stdio"
+
         with open(os.path.join(os.path.dirname(__file__), "runtime_dependencies.json"), "r") as f:
             d = json.load(f)
             del d["_description"]

src/multilspy/multilspy_config.py

@@ -4,6 +4,7 @@
 
 from enum import Enum
 from dataclasses import dataclass
+from typing import Optional
 
 class Language(str, Enum):
     """
@@ -34,6 +35,26 @@ class MultilspyConfig:
     trace_lsp_communication: bool = False
     start_independent_lsp_process: bool = True
 
+    # Optional path to a custom LSP binary/executable to use instead of the default.
+    # 
+    # For most language servers, this simply replaces the executable path. However, there
+    # are some exceptions:
+    # 
+    # - Java (EclipseJDTLS): Replaces only the launcher jar path. All Java/JVM arguments,
+    #   runtime setup, and configuration are preserved. The custom binary should be a path
+    #   to a JDTLS launcher jar file.
+    # 
+    # - Kotlin: Replaces only the Kotlin LSP executable path. All Java setup (JAVA_HOME, etc.)
+    #   is still performed and preserved, as it's required for Kotlin to function.
+    # 
+    # - C# (OmniSharp): Replaces only the OmniSharp executable path. All setup including
+    #   RazorOmnisharp DLL download is still performed, and the DLL path is still available
+    #   if needed by the custom binary.
+    # 
+    # For all other language servers (Rust, Python, Go, Ruby, C++), the custom binary
+    # path directly replaces the default executable with no other modifications.
+    custom_lsp_binary: Optional[str] = None
+
     @classmethod
     def from_dict(cls, env: dict):
         """