Set default for ${input} to empty string

Co-authored-by: Giancarlo Misasi <[email protected]>

Author: mfussenegger

doc/dap.txt

@@ -341,7 +341,7 @@ They are declared in an "inputs" array and each input must have the following pr
 - "id": the identifier of an input
 - "type": Either `pickString` or `promptString`
 - "description": Descriptive text shown to the user
-- "default": Default value
+- "default": Default value (Defaults to '' if not provided)
 
 `pickString` has an additional "options" property, which is an array of strings.
 These are shown to the user as options.

lua/dap/ext/vscode.lua

@@ -12,7 +12,7 @@ local function create_input(type_, input)
       if not vim.endswith(description, ': ') then
         description = description .. ': '
       end
-      return vim.fn.input(description, input.default)
+      return vim.fn.input(description, input.default or '')
     end
   elseif type_ == "pickString" then
     return function()
@@ -23,7 +23,7 @@ local function create_input(type_, input)
       local co = coroutine.running()
       vim.ui.select(options, opts, function(option)
         vim.schedule(function()
-          coroutine.resume(co, option or input.default)
+          coroutine.resume(co, option or input.default or '')
         end)
       end)
       return coroutine.yield()

tests/ext_vscode_spec.lua

@@ -189,4 +189,44 @@ describe('dap.ext.vscode', function()
     assert.are.same("bar", config.foo)
     end
   end)
+
+  it('supports promptString without default value', function()
+    local prompt
+    local default
+    vim.fn.input = function(prompt_, default_, _)
+      prompt = prompt_
+      default = default_
+      return 'Fake input'
+    end
+    local jsonstr = [[
+      {
+        "configurations": [
+          {
+            "type": "dummy",
+            "request": "launch",
+            "name": "Dummy",
+            "program": "${workspaceFolder}/${input:myInput}"
+          }
+        ],
+        "inputs": [
+          {
+            "id": "myInput",
+            "type": "promptString",
+            "description": "Your input"
+          }
+        ]
+      }
+    ]]
+    local configs = vscode._load_json(jsonstr)
+    local ok = false
+    local result
+    coroutine.wrap(function()
+      result = configs[1].program()
+      ok = true
+    end)()
+    vim.wait(1000, function() return ok end)
+    assert.are.same("${workspaceFolder}/Fake input", result)
+    assert.are.same("Your input: ", prompt)
+    assert.are.same("", default)
+  end)
 end)