win: executable(): full path without extension

Absolute path is considered executable even *without* an extension.

3 files changed, 89 insertions, 73 deletions

diff --git a/src/nvim/os/fs.c b/src/nvim/os/fs.c
index 4ca67d1f1a..7266e54b58 100644
--- a/src/nvim/os/fs.c
+++ b/src/nvim/os/fs.c
@@ -219,37 +219,42 @@ int os_exepath(char *buffer, size_t *size)
 bool os_can_exe(const char_u *name, char_u **abspath, bool use_path)
   FUNC_ATTR_NONNULL_ARG(1)
 {
-  // when use_path is false or if it's an absolute or relative path don't
-  // need to use $PATH.
-  if (!use_path || path_is_absolute_path(name)
-      || (name[0] == '.'
-          && (name[1] == '/' || (name[1] == '.' && name[2] == '/')))) {
+  bool no_path = !use_path || path_is_absolute_path(name);
+#ifndef WIN32
+  // If the filename is "qualified" (relative or absolute) do not check $PATH.
+  no_path |= (name[0] == '.'
+              && (name[1] == '/' || (name[1] == '.' && name[2] == '/')));
+#endif
+
+  if (no_path) {
 #ifdef WIN32
-    bool ok = is_executable(name);
+    const char *pathext = os_getenv("PATHEXT");
+    if (!pathext) {
+      pathext = ".com;.exe;.bat;.cmd";
+    }
+    bool ok = is_executable((char *)name) || is_executable_ext((char *)name,
+                                                               pathext);
 #else
     // Must have path separator, cannot execute files in the current directory.
-    bool ok = gettail_dir(name) != name && is_executable(name);
+    bool ok = gettail_dir(name) != name && is_executable((char *)name);
 #endif
     if (ok) {
       if (abspath != NULL) {
         *abspath = save_absolute_path(name);
       }
-
       return true;
     }
-
     return false;
   }
 
   return is_executable_in_path(name, abspath);
 }
 
-// Return true if "name" is an executable file, false if not or it doesn't
-// exist.
-static bool is_executable(const char_u *name)
+/// Returns true if `name` is an executable file.
+static bool is_executable(const char *name)
   FUNC_ATTR_NONNULL_ALL
 {
-  int32_t mode = os_getperm(name);
+  int32_t mode = os_getperm((char_u *)name);
 
   if (mode < 0) {
     return false;
@@ -264,6 +269,37 @@ static bool is_executable(const char_u *name)
 #endif
 }
 
+#ifdef WIN32
+/// Appends file extensions from `pathext` to `name` and returns true if any
+/// such combination is executable.
+static bool is_executable_ext(char *name, const char *pathext)
+  FUNC_ATTR_NONNULL_ALL
+{
+  xstrlcpy((char *)NameBuff, name, sizeof(NameBuff));
+  char *buf_end = xstrchrnul((char *)NameBuff, '\0');
+  for (const char *ext = pathext; *ext; ext++) {
+    // Skip the extension if there is no suffix after a '.'.
+    if (ext[0] == '.' && (ext[1] == '\0' || ext[1] == ENV_SEPCHAR)) {
+      ext++;
+      continue;
+    }
+
+    const char *ext_end = xstrchrnul(ext, ENV_SEPCHAR);
+    STRLCPY(buf_end, ext, ext_end - ext + 1);
+
+    if (is_executable((char *)NameBuff)) {
+      return true;
+    }
+
+    if (*ext_end != ENV_SEPCHAR) {
+      break;
+    }
+    ext = ext_end;
+  }
+  return false;
+}
+#endif
+
 /// Checks if a file is inside the `$PATH` and is executable.
 ///
 /// @param[in]  name The name of the executable.
@@ -294,11 +330,10 @@ static bool is_executable_in_path(const char_u *name, char_u **abspath)
   if (!pathext) {
     pathext = ".com;.exe;.bat;.cmd";
   }
-
   buf_len += strlen(pathext);
 #endif
 
-  char_u *buf = xmalloc(buf_len);
+  char *buf = xmalloc(buf_len);
 
   // Walk through all entries in $PATH to check if "name" exists there and
   // is an executable file.
@@ -307,50 +342,24 @@ static bool is_executable_in_path(const char_u *name, char_u **abspath)
   for (;; ) {
     char *e = xstrchrnul(p, ENV_SEPCHAR);
 
-    // Glue the directory from $PATH with `name` and save into buf.
+    // Combine the $PATH segment with `name`.
     STRLCPY(buf, p, e - p + 1);
-    append_path((char *)buf, (char *)name, buf_len);
+    append_path(buf, (char *)name, buf_len);
 
-    if (is_executable(buf)) {
-      // Check if the caller asked for a copy of the path.
-      if (abspath != NULL) {
-        *abspath = save_absolute_path(buf);
+#ifdef WIN32
+    bool ok = is_executable(buf) || is_executable_ext(buf, pathext);
+#else
+    bool ok = is_executable(buf);
+#endif
+    if (ok) {
+      if (abspath != NULL) {  // Caller asked for a copy of the path.
+        *abspath = save_absolute_path((char_u *)buf);
       }
 
       rv = true;
       goto end;
     }
 
-#ifdef WIN32
-    // Try appending file extensions from $PATHEXT to the name.
-    char *buf_end = xstrchrnul((char *)buf, '\0');
-    for (const char *ext = pathext; *ext; ext++) {
-      // Skip the extension if there is no suffix after a '.'.
-      if (ext[0] == '.' && (ext[1] == '\0' || ext[1] == ENV_SEPCHAR)) {
-        *ext++;
-        continue;
-      }
-
-      const char *ext_end = xstrchrnul(ext, ENV_SEPCHAR);
-      STRLCPY(buf_end, ext, ext_end - ext + 1);
-
-      if (is_executable(buf)) {
-        // Check if the caller asked for a copy of the path.
-        if (abspath != NULL) {
-          *abspath = save_absolute_path(buf);
-        }
-
-        rv = true;
-        goto end;
-      }
-
-      if (*ext_end != ENV_SEPCHAR) {
-        break;
-      }
-      ext = ext_end;
-    }
-#endif
-
     if (*e != ENV_SEPCHAR) {
       // End of $PATH without finding any executable called name.
       goto end;
diff --git a/src/nvim/path.c b/src/nvim/path.c
index 374d72ddd3..ea06fb8dde 100644
--- a/src/nvim/path.c
+++ b/src/nvim/path.c
@@ -995,12 +995,10 @@ static void uniquefy_paths(garray_T *gap, char_u *pattern)
     ga_remove_duplicate_strings(gap);
 }
 
-/*
- * Return the end of the directory name, on the first path
- * separator:
- * "/path/file", "/path/dir/", "/path//dir", "/file"
- *	 ^	       ^	     ^	      ^
- */
+/// Return the end of the directory name, on the first path
+/// separator:
+/// "/path/file", "/path/dir/", "/path//dir", "/file"
+///       ^             ^             ^        ^
 char_u *gettail_dir(const char_u *fname)
 {
   const char_u      *dir_end = fname;
@@ -2131,17 +2129,12 @@ int append_path(char *path, const char *to_append, size_t max_len)
   size_t current_length = strlen(path);
   size_t to_append_length = strlen(to_append);
 
-  // Do not append empty strings.
-  if (to_append_length == 0) {
-    return OK;
-  }
-
-  // Do not append a dot.
-  if (STRCMP(to_append, ".") == 0) {
+  // Do not append empty string or a dot.
+  if (to_append_length == 0 || strcmp(to_append, ".") == 0) {
     return OK;
   }
 
-  // Glue both paths with a slash.
+  // Combine the path segments, separated by a slash.
   if (current_length > 0 && !vim_ispathsep_nocolon(path[current_length-1])) {
     current_length += 1;  // Count the trailing slash.
 
@@ -2150,7 +2143,7 @@ int append_path(char *path, const char *to_append, size_t max_len)
       return FAIL;
     }
 
-    STRCAT(path, PATHSEPSTR);
+    xstrlcat(path, PATHSEPSTR, max_len);
   }
 
   // +1 for the NUL at the end.
@@ -2158,7 +2151,7 @@ int append_path(char *path, const char *to_append, size_t max_len)
     return FAIL;
   }
 
-  STRCAT(path, to_append);
+  xstrlcat(path, to_append, max_len);
   return OK;
 }
 
diff --git a/test/functional/eval/executable_spec.lua b/test/functional/eval/executable_spec.lua
index 13b9261d82..7948ddaa40 100644
--- a/test/functional/eval/executable_spec.lua
+++ b/test/functional/eval/executable_spec.lua
@@ -20,14 +20,8 @@ describe('executable()', function()
     -- Windows: siblings are in Nvim's "pseudo-$PATH".
     local expected = iswin() and 1 or 0
     if iswin() then
-      print('XXXXXXXXXXXXXXXXXXXXXXXXX')
-      print(helpers.eval('$PATH'))
-      print('XXXXXXXXXXXXXXXXXXXXXXXXX')
       -- $PATH on AppVeyor CI might be oversized, redefine it to a minimal one.
       clear({env={PATH=[[C:\Windows\system32;C:\Windows]]}})
-      print(helpers.eval('$PATH'))
-      print('XXXXXXXXXXXXXXXXXXXXXXXXX')
-      print(helpers.eval("echo glob(fnamemodify(exepath(v:progpath), ':h').'/*')"))
       eq('arg1=lemon;arg2=sky;arg3=tree;',
          call('system', sibling_exe..' lemon sky tree'))
     end
@@ -103,6 +97,26 @@ describe('executable() (Windows)', function()
     eq(0, call('executable', '.\\test_executable_zzz'))
   end)
 
+  it('full path with extension', function()
+    -- Some executable we can expect in the test env.
+    local exe = 'printargs-test'
+    local exedir = helpers.eval("fnamemodify(v:progpath, ':h')")
+    local exepath = exedir..'/'..exe..'.exe'
+    eq(1, call('executable', exepath))
+    eq('arg1=lemon;arg2=sky;arg3=tree;',
+       call('system', exepath..' lemon sky tree'))
+  end)
+
+  it('full path without extension', function()
+    -- Some executable we can expect in the test env.
+    local exe = 'printargs-test'
+    local exedir = helpers.eval("fnamemodify(v:progpath, ':h')")
+    local exepath = exedir..'/'..exe
+    eq('arg1=lemon;arg2=sky;arg3=tree;',
+       call('system', exepath..' lemon sky tree'))
+     eq(1, call('executable', exepath))
+  end)
+
   it('respects $PATHEXT when trying extensions on a filename', function()
     clear({env={PATHEXT='.zzz'}})
     for _,ext in ipairs(exts) do