leverage PATH for locating local executables (#283)

1. This is a breaking change for the following servers, which will have to be
reinstalled:

 - ltex
 - clangd

2. This is a breaking change for users who reach into the default options (for
   example via server:get_default_options()) to access the `cmd` property.
   nvim-lsp-installer no longer provides the `cmd` (except in a few
   instances), but instead provides an amended PATH which allows neovim's LSP
   client to locate the locally installed executable.

   To access the `cmd`, simply access it via lspconfig instead, for example
   like so:

    local default_config = require("lspconfig.server_configurations.rust_analyzer").default_config
    print("I can now access the cmd governed by lspconfig:", default_config.cmd)

3. This is a breaking change for 3rd party use cases that makes use of the
   `executable()` APIs (e.g., `npm.executable(root_dir, "tsserver")`). The
   recommended usage is to instead to use the canonical name of the command
   ("tsserver"), while providing an amended PATH, for example:

    local npm = require("nvim-lsp-installer.installers.npm")
    local server = server.Server:new {
        ...,
        root_dir = root_dir,
        installer = npm.packages { "tsserver" },
        default_options = {
            cmd = { "tsserver" },
            cmd_env = npm.env(root_dir),
        }
    }

1 files changed, 5 insertions, 15 deletions

diff --git a/lua/nvim-lsp-installer/servers/clangd/init.lua b/lua/nvim-lsp-installer/servers/clangd/init.lua
index 5ec3e351..7aea65c3 100644
--- a/lua/nvim-lsp-installer/servers/clangd/init.lua
+++ b/lua/nvim-lsp-installer/servers/clangd/init.lua
@@ -1,13 +1,12 @@
 local server = require "nvim-lsp-installer.server"
 local path = require "nvim-lsp-installer.path"
+local process = require "nvim-lsp-installer.process"
 local Data = require "nvim-lsp-installer.data"
 local std = require "nvim-lsp-installer.installers.std"
 local platform = require "nvim-lsp-installer.platform"
 local context = require "nvim-lsp-installer.installers.context"
 
 return function(name, root_dir)
-    local script_name = platform.is_win and "clangd.bat" or "clangd"
-
     return server.Server:new {
         name = name,
         root_dir = root_dir,
@@ -26,22 +25,13 @@ return function(name, root_dir)
                 return std.unzip_remote(ctx.github_release_file)
             end),
             context.capture(function(ctx)
-                -- Preferably we'd not have to write a script file that captures the installed version.
-                -- But in order to not break backwards compatibility for existing installations of clangd, we do it.
-                return std.executable_alias(
-                    script_name,
-                    path.concat {
-                        root_dir,
-                        ("clangd_%s"):format(ctx.requested_server_version),
-                        "bin",
-                        platform.is_win and "clangd.exe" or "clangd",
-                    }
-                )
+                return std.rename(("clangd_%s"):format(ctx.requested_server_version), "clangd")
             end),
-            std.chmod("+x", { "clangd" }),
         },
         default_options = {
-            cmd = { path.concat { root_dir, script_name } },
+            cmd_env = {
+                PATH = process.extend_path { path.concat { root_dir, "clangd", "bin" } },
+            },
         },
     }
 end