fix: don't auto install servers when headless (#175)

You should be able to run headless commands without mason-lspconfig starting installations in the background with
limited ability to wait until they're done.

lua/mason-lspconfig/init.lua

@@ -1,5 +1,6 @@
 local _ = require "mason-core.functional"
 local log = require "mason-core.log"
+local platform = require "mason-core.platform"
 
 local M = {}
 
@@ -19,7 +20,7 @@ function M.setup(config)
         log.error("Failed to set up lspconfig integration.", err)
     end
 
-    if #settings.current.ensure_installed > 0 then
+    if not platform.is_headless and #settings.current.ensure_installed > 0 then
         require "mason-lspconfig.ensure_installed"()
     end
 

lua/mason-lspconfig/lspconfig_hook.lua

@@ -7,6 +7,9 @@ local memoized_set = _.memoize(_.set_of)
 
 ---@param server_name string
 local function should_auto_install(server_name)
+    if platform.is_headless then
+        return false
+    end
     local settings = require "mason-lspconfig.settings"
 
     if settings.current.automatic_installation == true then

tests/mason-lspconfig/setup_spec.lua

@@ -5,6 +5,7 @@ local stub = require "luassert.stub"
 local Pkg = require "mason-core.package"
 local filetype_mappings = require "mason-lspconfig.mappings.filetype"
 local mason_lspconfig = require "mason-lspconfig"
+local platform = require "mason-core.platform"
 local registry = require "mason-registry"
 local server_mappings = require "mason-lspconfig.mappings.server"
 
@@ -51,6 +52,7 @@ describe("mason-lspconfig setup", function()
             local fail_dummy = registry.get_package "fail_dummy"
             spy.on(Pkg, "install")
 
+            platform.is_headless = false
             mason_lspconfig.setup { ensure_installed = { "dummylsp@1.0.0", "fail_dummylsp" } }
 
             assert.spy(Pkg.install).was_called(2)
@@ -63,11 +65,24 @@ describe("mason-lspconfig setup", function()
         end)
     )
 
+    it(
+        "should not install servers listed in ensure_installed when headless",
+        async_test(function()
+            spy.on(Pkg, "install")
+
+            platform.is_headless = true
+            mason_lspconfig.setup { ensure_installed = { "dummylsp@1.0.0", "fail_dummylsp" } }
+
+            assert.spy(Pkg.install).was_called(0)
+        end)
+    )
+
     it(
         "should notify when installing servers listed in ensure_installed",
         async_test(function()
             spy.on(vim, "notify")
 
+            platform.is_headless = false
             mason_lspconfig.setup { ensure_installed = { "dummylsp", "fail_dummylsp" } }
 
             assert
@@ -100,6 +115,7 @@ describe("mason-lspconfig setup", function()
             spy.on(Pkg, "install")
             spy.on(vim, "notify")
 
+            platform.is_headless = false
             mason_lspconfig.setup { automatic_installation = true }
             local lspconfig = require "lspconfig"
             lspconfig.dummylsp.setup {}
@@ -139,6 +155,7 @@ describe("mason-lspconfig setup", function()
             local dummy2 = registry.get_package "dummy2"
             spy.on(Pkg, "install")
 
+            platform.is_headless = false
             mason_lspconfig.setup { automatic_installation = true }
             local lspconfig = require "lspconfig"
             spy.on(lspconfig.dummylsp, "setup")
@@ -159,6 +176,23 @@ describe("mason-lspconfig setup", function()
         end)
     )
 
+    it(
+        "should not automatically install servers when headless",
+        async_test(function()
+            spy.on(Pkg, "install")
+
+            platform.is_headless = true
+            mason_lspconfig.setup { automatic_installation = true }
+            local lspconfig = require "lspconfig"
+            spy.on(lspconfig.dummylsp, "setup")
+            spy.on(lspconfig.dummy2lsp, "setup")
+            lspconfig.dummylsp.setup {}
+            lspconfig.dummy2lsp.setup {}
+
+            assert.spy(Pkg.install).was_called(0)
+        end)
+    )
+
     it("should apply mason-lspconfig server configs", function()
         stub(registry, "is_installed")
         registry.is_installed.on_call_with("dummy").returns(true)
@@ -247,6 +281,7 @@ describe("mason-lspconfig setup_handlers", function()
 
     it("should print warning when providing invalid server entries in ensure_installed", function()
         spy.on(vim, "notify")
+        platform.is_headless = false
         mason_lspconfig.setup {
             ensure_installed = { "yamllint", "hadolint" },
         }