Alex Henrie : cmd: Handle `if exist` with an empty string argument.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: 859d5e68ddec5156f49efb3c1126db02691416af
URL:    https://gitlab.winehq.org/wine/wine/-/commit/859d5e68ddec5156f49efb3c1126db0...

Author: Alex Henrie <alexhenrie24(a)gmail.com>
Date:   Sat Sep  2 18:45:30 2023 -0600

cmd: Handle `if exist` with an empty string argument.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=55505

---

 programs/cmd/builtins.c                  | 15 +++++++++------
 programs/cmd/tests/test_builtins.cmd     |  5 +++++
 programs/cmd/tests/test_builtins.cmd.exp |  1 +
 3 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/programs/cmd/builtins.c b/programs/cmd/builtins.c
index 419e812103a..ca703af52ec 100644
--- a/programs/cmd/builtins.c
+++ b/programs/cmd/builtins.c
@@ -2841,13 +2841,16 @@ int evaluate_if_condition(WCHAR *p, WCHAR **command, int *test, int *negate)
     WCHAR *param = WCMD_parameter(p, 1+(*negate), NULL, FALSE, FALSE);
     int    len = lstrlenW(param);
 
-    if (!len) goto syntax_err;
-    /* FindFirstFile does not like a directory path ending in '\' or '/', append a '.' */
-    if (param[len-1] == '\\' || param[len-1] == '/') lstrcatW(param, L".");
+    if (!len) {
+        *test = FALSE;
+    } else {
+        /* FindFirstFile does not like a directory path ending in '\' or '/', so append a '.' */
+        if (param[len-1] == '\\' || param[len-1] == '/') wcscat(param, L".");
 
-    hff = FindFirstFileW(param, &fd);
-    *test = (hff != INVALID_HANDLE_VALUE );
-    if (*test) FindClose(hff);
+        hff = FindFirstFileW(param, &fd);
+        *test = (hff != INVALID_HANDLE_VALUE);
+        if (*test) FindClose(hff);
+    }
 
     WCMD_parameter(p, 2+(*negate), command, FALSE, FALSE);
   }
diff --git a/programs/cmd/tests/test_builtins.cmd b/programs/cmd/tests/test_builtins.cmd
index 28b935ad521..08595933622 100644
--- a/programs/cmd/tests/test_builtins.cmd
+++ b/programs/cmd/tests/test_builtins.cmd
@@ -1176,6 +1176,11 @@ if exist "subdir/" (
 ) else (
    echo ERROR exist subdir with / and quotes not working
 )
+if not exist "" (
+    echo exist empty string works
+) else (
+    echo exist empty string broken
+)
 del foo subdir\bar
 rd subdir
 
diff --git a/programs/cmd/tests/test_builtins.cmd.exp b/programs/cmd/tests/test_builtins.cmd.exp
index 57e72a77387..85e734b048a 100644
--- a/programs/cmd/tests/test_builtins.cmd.exp
+++ b/programs/cmd/tests/test_builtins.cmd.exp
@@ -833,6 +833,7 @@ exist subdir with \ and quotes ok
 exist subdir with /. ok
 exist subdir with / ok
 exist subdir with / and quotes ok
+exist empty string works
 ------ for numbers
 negative numbers handled
 negative numbers handled