feat(terminator): send SIGKILL after some delay after SIGTERM (#727)

Give a very generous grace period for processes to terminate gracefully
before forcefully killing them, to ensure none linger.

3 files changed, 57 insertions, 27 deletions

diff --git a/lua/mason/init.lua b/lua/mason/init.lua
index f6c46ef4..62a66bea 100644
--- a/lua/mason/init.lua
+++ b/lua/mason/init.lua
@@ -16,7 +16,7 @@ local function setup_autocmds()
 
     vim.api.nvim_create_autocmd("VimLeavePre", {
         callback = function()
-            require("mason.terminator").terminate()
+            require("mason.terminator").terminate(5000)
         end,
         once = true,
     })
diff --git a/lua/mason/terminator.lua b/lua/mason/terminator.lua
index 7a9290a0..ea4bd5a2 100644
--- a/lua/mason/terminator.lua
+++ b/lua/mason/terminator.lua
@@ -22,21 +22,32 @@ local M = {}
 
 ---@async
 ---@param handles InstallHandle[]
-local function terminate_handles(handles)
+---@param grace_ms integer
+local function terminate_handles(handles, grace_ms)
     a.wait_all(vim.tbl_map(
         ---@param handle InstallHandle
         function(handle)
-            if not handle:is_closed() then
-                handle:terminate()
-            end
             return function()
-                a.wait(function(resolve)
-                    if handle:is_closed() then
-                        resolve()
-                    else
-                        handle:once("closed", resolve)
-                    end
-                end)
+                a.wait_first {
+                    function()
+                        if not handle:is_closed() then
+                            handle:terminate()
+                        end
+                        a.wait(function(resolve)
+                            if handle:is_closed() then
+                                resolve()
+                            else
+                                handle:once("closed", resolve)
+                            end
+                        end)
+                    end,
+                    function()
+                        a.sleep(grace_ms)
+                        if not handle:is_closed() then
+                            handle:kill(9) -- SIGKILL
+                        end
+                    end,
+                }
             end
         end,
         handles
@@ -57,7 +68,8 @@ function M.setup()
     end)
 end
 
-function M.terminate()
+---@param grace_ms integer
+function M.terminate(grace_ms)
     local handles = vim.tbl_keys(active_handles)
     if #handles > 0 then
         local package_names = vim.tbl_map(function(h)
@@ -76,14 +88,7 @@ function M.terminate()
 
         -- 2. Synchronously terminate all installation handles.
         a.run_blocking(function()
-            a.wait_first {
-                function()
-                    a.sleep(5000)
-                end,
-                function()
-                    terminate_handles(handles)
-                end,
-            }
+            terminate_handles(handles, grace_ms)
         end)
 
         -- 3. Schedule error message to be displayed so that Neovim prints it to the tty.
diff --git a/tests/mason/terminator_spec.lua b/tests/mason/terminator_spec.lua
index 9f243086..2058d4e2 100644
--- a/tests/mason/terminator_spec.lua
+++ b/tests/mason/terminator_spec.lua
@@ -1,4 +1,5 @@
 local stub = require "luassert.stub"
+local match = require "luassert.match"
 local spy = require "luassert.spy"
 local a = require "mason-core.async"
 local registry = require "mason-registry"
@@ -14,6 +15,7 @@ describe("terminator", function()
     it(
         "should terminate all active handles on nvim exit",
         async_test(function()
+            spy.on(InstallHandle, "terminate")
             local dummy = registry.get_package "dummy"
             local dummy2 = registry.get_package "dummy2"
             for _, pkg in ipairs { dummy, dummy2 } do
@@ -25,11 +27,9 @@ describe("terminator", function()
 
             dummy:install()
             dummy2:install()
-            spy.on(InstallHandle, "terminate")
+            terminator.terminate(5000)
 
-            terminator.terminate()
             a.scheduler()
-
             assert.spy(InstallHandle.terminate).was_called(2)
         end)
     )
@@ -39,6 +39,7 @@ describe("terminator", function()
         async_test(function()
             spy.on(vim.api, "nvim_echo")
             spy.on(vim.api, "nvim_err_writeln")
+            spy.on(InstallHandle, "terminate")
             local dummy = registry.get_package "dummy"
             local dummy2 = registry.get_package "dummy2"
             for _, pkg in ipairs { dummy, dummy2 } do
@@ -50,9 +51,7 @@ describe("terminator", function()
 
             dummy:install()
             dummy2:install()
-            spy.on(InstallHandle, "terminate")
-
-            terminator.terminate()
+            terminator.terminate(5000)
 
             assert.spy(vim.api.nvim_echo).was_called(1)
             assert.spy(vim.api.nvim_echo).was_called_with({
@@ -72,4 +71,30 @@ describe("terminator", function()
             ]])
         end)
     )
+
+    it(
+        "should send SIGTERM and then SIGKILL after grace period",
+        async_test(function()
+            spy.on(InstallHandle, "kill")
+            local dummy = registry.get_package "dummy"
+            stub(dummy.spec, "install")
+            dummy.spec.install.invokes(function(ctx)
+                -- your signals have no power here
+                ctx.spawn.bash { "-c", "function noop { :; }; trap noop SIGTERM; sleep 999999;" }
+            end)
+
+            local handle = dummy:install()
+
+            assert.wait_for(function()
+                assert.spy(dummy.spec.install).was_called()
+            end)
+            terminator.terminate(50)
+
+            assert.wait_for(function()
+                assert.spy(InstallHandle.kill).was_called(2)
+                assert.spy(InstallHandle.kill).was_called_with(match.is_ref(handle), 15) -- SIGTERM
+                assert.spy(InstallHandle.kill).was_called_with(match.is_ref(handle), 9) -- SIGKILL
+            end)
+        end)
+    )
 end)