getcwd(): Return empty string if CWD is invalid. #5292

Closes #5291

Restores behaviour identical to Vim. If the user calls the VimScript
function 'getcwd()' and the working directory cannot be found (for
example because the directory has been deleted since the last time it
was used) an empty string needs to be returned instead of throwing an
error.

2 files changed, 27 insertions, 13 deletions

diff --git a/src/nvim/eval.c b/src/nvim/eval.c
index bfe4707dab..211419f7a6 100644
--- a/src/nvim/eval.c
+++ b/src/nvim/eval.c
@@ -9776,26 +9776,20 @@ static void f_getcwd(typval_T *argvars, typval_T *rettv, FunPtr fptr)
       if (from) {
         break;
       }
-    case kCdScopeTab:  // FALLTHROUGH
+    case kCdScopeTab:         // FALLTHROUGH
       assert(tp);
       from = tp->localdir;
       if (from) {
         break;
       }
-    case kCdScopeGlobal:  // FALLTHROUGH
-      // The `globaldir` variable is not always set.
-      if (globaldir) {
+    case kCdScopeGlobal:      // FALLTHROUGH
+      if (globaldir) {        // `globaldir` is not always set.
         from = globaldir;
-      } else {
-        // We have to copy the OS path directly into output string.
-        if (os_dirname(cwd, MAXPATHL) == FAIL) {
-          EMSG(_("E41: Could not display path."));
-          goto end;
-        }
+      } else if (os_dirname(cwd, MAXPATHL) == FAIL) {  // Get the OS CWD.
+        from = (char_u *)"";  // Return empty string on failure.
       }
       break;
-    case kCdScopeInvalid:
-      // We should never get here
+    case kCdScopeInvalid:     // We should never get here
       assert(false);
   }
 
@@ -9807,7 +9801,7 @@ static void f_getcwd(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 #ifdef BACKSLASH_IN_FILENAME
   slash_adjust(rettv->vval.v_string);
 #endif
-end:
+
   xfree(cwd);
 }
 
diff --git a/test/functional/ex_cmds/cd_spec.lua b/test/functional/ex_cmds/cd_spec.lua
index 74432dbe00..85e1a5c5d5 100644
--- a/test/functional/ex_cmds/cd_spec.lua
+++ b/test/functional/ex_cmds/cd_spec.lua
@@ -269,3 +269,23 @@ for _, cmd in ipairs {'getcwd', 'haslocaldir'} do
   end)
 end
 
+describe("getcwd()", function ()
+  local temp_dir = "Xtest-functional-ex_cmds-cd_spec.temp"
+  before_each(function()
+    clear()
+    lfs.mkdir(temp_dir)
+  end)
+
+  after_each(function()
+    helpers.rmdir(temp_dir)
+  end)
+
+  it("returns empty string if working directory does not exist", function()
+    execute("cd " .. temp_dir)
+    helpers.wait()
+    helpers.rmdir(temp_dir)
+    eq("", helpers.eval("getcwd()"))
+  end)
+end)
+
+