maint: add assertions to placate static analysis tools

A static analysis tool (http://labs.oracle.com/projects/parfait/)
produced some false positive diagnostics.  Add assertions to help
it understand that the code is correct.
* src/stty.c: Include <assert.h>.
(display_changed): Add an assertion to placate parfait.
(display_all): Likewise.
* src/sort.c: Include <assert.h>.
(main): Add an assertion to placate parfait.
* src/fmt.c: Include <assert.h>.
(get_paragraph): Add an assertion to placate parfait.

diff --git a/src/fmt.c b/src/fmt.c
index 308b645553d847a6b84620ab72e40073072a846c..3da198e1628172af99eafb20f0d832ad0e99cb24 100644 (file)
--- a/src/fmt.c
+++ b/src/fmt.c
@@ -20,6 +20,7 @@
 #include <stdio.h>
 #include <sys/types.h>
 #include <getopt.h>
+#include <assert.h>
 
 /* Redefine.  Otherwise, systems (Unicos for one) with headers that define
    it to be a type get syntax errors for the variable declaration below.  */
@@ -610,6 +611,11 @@ get_paragraph (FILE *f)
       while (same_para (c) && in_column == other_indent)
         c = get_line (f, c);
     }
+
+  /* Tell static analysis tools that using word_limit[-1] is ok.
+     word_limit is guaranteed to have been incremented by get_line.  */
+  assert (word < word_limit);
+
   (word_limit - 1)->period = (word_limit - 1)->final = true;
   next_char = c;
   return true;

diff --git a/src/sort.c b/src/sort.c
index 493e7f17392952884711b24e73234ce7be4025a5..2593a2a6ebae0259749b179bb8eb5350757a78d7 100644 (file)
--- a/src/sort.c
+++ b/src/sort.c
@@ -28,6 +28,7 @@
 #include <sys/types.h>
 #include <sys/wait.h>
 #include <signal.h>
+#include <assert.h>
 #include "system.h"
 #include "argmatch.h"
 #include "error.h"
@@ -4243,6 +4244,10 @@ main (int argc, char **argv)
                           char const *optarg1 = argv[optind++];
                           s = parse_field_count (optarg1 + 1, &key->eword,
                                              N_("invalid number after '-'"));
+                          /* When called with a non-NULL message ID,
+                             parse_field_count cannot return NULL.  Tell static
+                             analysis tools that dereferencing S is safe.  */
+                          assert (s);
                           if (*s == '.')
                             s = parse_field_count (s + 1, &key->echar,
                                                N_("invalid number after '.'"));

diff --git a/src/stty.c b/src/stty.c
index eb07f853f48ae2b6ccd8e5dce27252ff506823b8..a3fc3dd3983a4ad0742261135db2e3c054036914 100644 (file)
--- a/src/stty.c
+++ b/src/stty.c
@@ -52,6 +52,7 @@
 #endif
 #include <getopt.h>
 #include <stdarg.h>
+#include <assert.h>
 
 #include "system.h"
 #include "error.h"
@@ -1538,6 +1539,12 @@ display_changed (struct termios *mode)
 
       bitsp = mode_type_flag (mode_info[i].type, mode);
       mask = mode_info[i].mask ? mode_info[i].mask : mode_info[i].bits;
+
+      /* bitsp would be NULL only for "combination" modes, yet those
+         are filtered out above via the OMIT flag.  Tell static analysis
+         tools that it's ok to dereference bitsp here.  */
+      assert (bitsp);
+
       if ((*bitsp & mask) == mode_info[i].bits)
         {
           if (mode_info[i].flags & SANE_UNSET)
@@ -1615,6 +1622,7 @@ display_all (struct termios *mode, char const *device_name)
 
       bitsp = mode_type_flag (mode_info[i].type, mode);
       mask = mode_info[i].mask ? mode_info[i].mask : mode_info[i].bits;
+      assert (bitsp); /* See the identical assertion and comment above.  */
       if ((*bitsp & mask) == mode_info[i].bits)
         wrapf ("%s", mode_info[i].name);
       else if (mode_info[i].flags & REV)