fix(context): don't write exec wrapper file if it already exists (#1261)

2 files changed, 47 insertions, 0 deletions

diff --git a/lua/mason-core/installer/context.lua b/lua/mason-core/installer/context.lua
index e42393ff..52fbcf16 100644
--- a/lua/mason-core/installer/context.lua
+++ b/lua/mason-core/installer/context.lua
@@ -342,6 +342,9 @@ local BATCH_TEMPLATE = _.dedent [[
 ---@param env table<string, string>?
 ---@return string # The created executable filename.
 function InstallContext:write_shell_exec_wrapper(new_executable_rel_path, command, env)
+    if self.fs:file_exists(new_executable_rel_path) or self.fs:dir_exists(new_executable_rel_path) then
+        error(("Cannot write exec wrapper to %q because the file already exists."):format(new_executable_rel_path), 0)
+    end
     return platform.when {
         unix = function()
             local std = require "mason-core.managers.std"
diff --git a/tests/mason-core/installer/context_spec.lua b/tests/mason-core/installer/context_spec.lua
index efd632e3..af99089f 100644
--- a/tests/mason-core/installer/context_spec.lua
+++ b/tests/mason-core/installer/context_spec.lua
@@ -19,6 +19,10 @@ describe("installer", function()
         local handle = InstallHandleGenerator "dummy"
         local ctx = InstallContextGenerator(handle)
         stub(ctx.fs, "write_file")
+        stub(ctx.fs, "file_exists")
+        stub(ctx.fs, "dir_exists")
+        ctx.fs.file_exists.on_call_with(match.is_ref(ctx.fs), "my-executable").returns(false)
+        ctx.fs.dir_exists.on_call_with(match.is_ref(ctx.fs), "my-executable").returns(false)
         stub(std, "chmod")
 
         ctx:write_shell_exec_wrapper("my-executable", "bash -c 'echo $GREETING'", {
@@ -44,6 +48,10 @@ exec bash -c 'echo $GREETING' "$@"]]
         local handle = InstallHandleGenerator "dummy"
         local ctx = InstallContextGenerator(handle)
         stub(ctx.fs, "write_file")
+        stub(ctx.fs, "file_exists")
+        stub(ctx.fs, "dir_exists")
+        ctx.fs.file_exists.on_call_with(match.is_ref(ctx.fs), "my-executable").returns(false)
+        ctx.fs.dir_exists.on_call_with(match.is_ref(ctx.fs), "my-executable").returns(false)
         stub(std, "chmod")
 
         ctx:write_shell_exec_wrapper("my-executable", "cmd.exe /C echo %GREETING%", {
@@ -60,6 +68,23 @@ cmd.exe /C echo %GREETING% %*]]
         )
     end)
 
+    it("should not write shell exec wrapper if new executable path already exists", function()
+        local exec_rel_path = path.concat { "obscure", "path", "to", "server" }
+        local handle = InstallHandleGenerator "dummy"
+        local ctx = InstallContextGenerator(handle)
+        stub(ctx.fs, "file_exists")
+        stub(ctx.fs, "dir_exists")
+        ctx.fs.file_exists.on_call_with(match.is_ref(ctx.fs), exec_rel_path).returns(true)
+        ctx.fs.file_exists.on_call_with(match.is_ref(ctx.fs), "my-wrapper-script").returns(true)
+        ctx.fs.dir_exists.on_call_with(match.is_ref(ctx.fs), "my-wrapper-script").returns(true)
+
+        local err = assert.has_error(function()
+            ctx:write_shell_exec_wrapper("my-wrapper-script", "contents")
+        end)
+
+        assert.equals([[Cannot write exec wrapper to "my-wrapper-script" because the file already exists.]], err)
+    end)
+
     it("should write Node exec wrapper", function()
         local js_rel_path = path.concat { "some", "obscure", "path", "server.js" }
         local dummy = registry.get_package "dummy"
@@ -79,6 +104,25 @@ cmd.exe /C echo %GREETING% %*]]
         )
     end)
 
+    it("should write Ruby exec wrapper", function()
+        local js_rel_path = path.concat { "some", "obscure", "path", "server.js" }
+        local dummy = registry.get_package "dummy"
+        local handle = InstallHandleGenerator "dummy"
+        local ctx = InstallContextGenerator(handle)
+        stub(ctx, "write_shell_exec_wrapper")
+        stub(ctx.fs, "file_exists")
+        ctx.fs.file_exists.on_call_with(match.is_ref(ctx.fs), js_rel_path).returns(true)
+
+        ctx:write_ruby_exec_wrapper("my-wrapper-script", js_rel_path)
+
+        assert.spy(ctx.write_shell_exec_wrapper).was_called(1)
+        assert.spy(ctx.write_shell_exec_wrapper).was_called_with(
+            match.is_ref(ctx),
+            "my-wrapper-script",
+            ("ruby %q"):format(path.concat { dummy:get_install_path(), js_rel_path })
+        )
+    end)
+
     it("should not write Node exec wrapper if the target script doesn't exist", function()
         local js_rel_path = path.concat { "some", "obscure", "path", "server.js" }
         local handle = InstallHandleGenerator "dummy"