refactor: Remove strncpy/STRNCPY. (#6008)

Closes #731
References #851

Note: This does not remove some intentional legacy usages of strncpy.
      - memcpy isn't equivalent because it doesn't check the string
        length of `src`, and doesn't zero-out the remainder of `dst`.
      - xstrlcpy isn't equivalent because it doesn't zero-out the
        remainder of `dst`. Some Vim logic depends on that (e.g.
        ex_append which calls vim_strnsave).

Helped-by: Douglas Schneider <ds3@ualberta.ca>
Helped-by: oni-link <knil.ino@gmail.com>
Helped-by: James McCoy <jamessan@jamessan.com>

1 files changed, 8 insertions, 3 deletions

diff --git a/src/clint.py b/src/clint.py
index df71282362..4fa78d3c82 100755
--- a/src/clint.py
+++ b/src/clint.py
@@ -3167,14 +3167,19 @@ def CheckLanguage(filename, clean_lines, linenum, file_extension,
     if Search(r'\bsprintf\b', line):
         error(filename, linenum, 'runtime/printf', 5,
               'Use snprintf instead of sprintf.')
-    match = Search(r'\b(STRCPY|strcpy)\b', line)
+    match = Search(r'\b(strncpy|STRNCPY)\b', line)
+    if match:
+        error(filename, linenum, 'runtime/printf', 4,
+              'Use xstrlcpy or snprintf instead of %s (unless this is from Vim)'
+              % match.group(1))
+    match = Search(r'\b(strcpy)\b', line)
     if match:
         error(filename, linenum, 'runtime/printf', 4,
               'Use xstrlcpy or snprintf instead of %s' % match.group(1))
-    match = Search(r'\b(STRNCAT|strncat)\b', line)
+    match = Search(r'\b(STRNCAT|strncat|strcat)\b', line)
     if match:
         error(filename, linenum, 'runtime/printf', 4,
-              'Use xstrlcat instead of %s' % match.group(1))
+              'Use xstrlcat or snprintf instead of %s' % match.group(1))
 
     # Check for suspicious usage of "if" like
     # } if (a == b) {