Re: head - Re: branch-1_4 patsubst bug, and missing arguments

[Eric Blake]

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According to Eric Blake on 8/25/2006 4:06 PM:
> 
> And with that declaration, here goes.  This patch touches a lot of files,
> but the core things it does are fix struct m4_builtin to be 0-based, add a
> bit to state when a macro must be called for side effects even when
> warning about too few arguments, then fix patsubst to be reliable, and fix
> the fallout.  There are still a number of issues in modules/m4.c that need
> porting, but I think modules/gnu.c is now fully ported.

Looking back, it doesn't make sense for a blind macro to take 0 arguments,
so I added a check for that and fixed the two macros that fell short in
this area.

2006-08-28  Eric Blake  <address@hidden>

        * m4/utility.c (m4_bad_argc): Move assertion out of hot path...
        * m4/module.c (install_builtin_table): ...to here, and add
        assertion that blind macros require arguments.
        * m4/m4module.h (struct m4_builtin): Document restrictions that
        must be met during module loading.
        * modules/gnu.c (changeresyntax, changesyntax): These are blind,
        so require an argument to avoid triggering assertion.
        (debugfile): Tweak error message.

- --
Life is short - so eat dessert first!

Eric Blake             address@hidden
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Index: m4/m4module.h
===================================================================
RCS file: /sources/m4/m4/m4/m4module.h,v
retrieving revision 1.80
diff -u -p -r1.80 m4module.h
--- m4/m4module.h       25 Aug 2006 22:06:42 -0000      1.80
+++ m4/m4module.h       28 Aug 2006 12:41:09 -0000
@@ -44,11 +44,15 @@ typedef void   m4_builtin_func  (m4 *, m
 
 /* The value of m4_builtin flags is built from these:  */
 enum {
-  /* set if macro can handle non-text tokens, such as builtin macro tokens */
+  /* Set if macro can handle non-text tokens, such as builtin macro
+     tokens; if clear, non-text tokens are flattened to the empty
+     string before invoking the builtin.  */
   M4_BUILTIN_GROKS_MACRO       = (1 << 0),
-  /* set if macro should only be recognized with arguments */
+  /* Set if macro should only be recognized with arguments; may only
+     be set if min_args is nonzero.  */
   M4_BUILTIN_BLIND             = (1 << 1),
-  /* set if macro has side effects even when there are too few arguments */
+  /* set if macro has side effects even when there are too few
+     arguments; may only be set if min_args is nonzero.  */
   M4_BUILTIN_SIDE_EFFECT       = (1 << 2)
 };
 
@@ -58,7 +62,8 @@ struct m4_builtin
   const char *     name;       /* name found by builtin, printed by dumpdef */
   int              flags;      /* bitwise OR of M4_BUILTIN_* bits */
   unsigned int     min_args;   /* 0-based minimum number of arguments */
-  unsigned int     max_args;   /* max arguments, UINT_MAX if unlimited */
+  /* max arguments, UINT_MAX if unlimited; must be >= min_args */
+  unsigned int     max_args;
 };
 
 struct m4_macro
Index: m4/module.c
===================================================================
RCS file: /sources/m4/m4/m4/module.c,v
retrieving revision 1.40
diff -u -p -r1.40 module.c
--- m4/module.c 25 Aug 2006 22:06:42 -0000      1.40
+++ m4/module.c 28 Aug 2006 12:41:09 -0000
@@ -145,6 +145,12 @@ install_builtin_table (m4 *context, lt_d
          m4_symbol_value *value = m4_symbol_value_create ();
          char *           name;
 
+         /* Sanity check that builtins meet the required interface.  */
+         assert (bp->min_args <= bp->max_args);
+         assert (bp->min_args > 0
+                 || (bp->flags & (M4_BUILTIN_BLIND
+                                  | M4_BUILTIN_SIDE_EFFECT)) == 0);
+
          m4_set_symbol_value_func (value, bp->func);
          VALUE_HANDLE   (value)        = handle;
          VALUE_FLAGS    (value)        = bp->flags;
Index: m4/utility.c
===================================================================
RCS file: /sources/m4/m4/m4/utility.c,v
retrieving revision 1.45
diff -u -p -r1.45 utility.c
--- m4/utility.c        25 Aug 2006 22:06:42 -0000      1.45
+++ m4/utility.c        28 Aug 2006 12:41:09 -0000
@@ -42,9 +42,6 @@ bool
 m4_bad_argc (m4 *context, int argc, m4_symbol_value **argv,
             unsigned int min, unsigned int max, bool side_effect)
 {
-  assert (min <= max);
-  assert (min > 0 || ! side_effect);
-
   if (argc - 1 < min)
     {
       m4_warn (context, 0, _("Warning: %s: too few arguments: %d < %d"),
Index: modules/gnu.c
===================================================================
RCS file: /sources/m4/m4/modules/gnu.c,v
retrieving revision 1.51
diff -u -p -r1.51 gnu.c
--- modules/gnu.c       25 Aug 2006 22:06:42 -0000      1.51
+++ modules/gnu.c       28 Aug 2006 12:41:09 -0000
@@ -49,8 +49,8 @@
   BUILTIN (__line__,   false,  false,  false,  0,      0  )    \
   BUILTIN (__program__,        false,  false,  false,  0,      0  )    \
   BUILTIN (builtin,    false,  true,   false,  1,      -1 )    \
-  BUILTIN (changeresyntax,false,true,  false,  0,      1  )    \
-  BUILTIN (changesyntax,false, true,   false,  0,      -1 )    \
+  BUILTIN (changeresyntax,false,true,  false,  1,      1  )    \
+  BUILTIN (changesyntax,false, true,   false,  1,      -1 )    \
   BUILTIN (debugmode,  false,  false,  false,  0,      1  )    \
   BUILTIN (debugfile,  false,  false,  false,  0,      1  )    \
   BUILTIN (esyscmd,    false,  true,   true,   1,      1  )    \
@@ -349,7 +349,7 @@ m4_resyntax_encode_safe (m4 *context, co
 
 
 /**
- * changeresyntax([RESYNTAX-SPEC])
+ * changeresyntax(RESYNTAX-SPEC)
  **/
 M4BUILTIN_HANDLER (changeresyntax)
 {
@@ -360,11 +360,10 @@ M4BUILTIN_HANDLER (changeresyntax)
 }
 
 
-/* Change the current input syntax.  The function m4_set_syntax () lives
-   in syntax.c.  For compability reasons, this function is not called,
-   if not followed by a SYNTAX_OPEN.  Also, any changes to comment
-   delimiters and quotes made here will be overridden by a call to
-   `changecom' or `changequote'.  */
+/* Change the current input syntax.  The function m4_set_syntax ()
+   lives in syntax.c.  Any changes to comment delimiters and quotes
+   made here will be overridden by a call to `changecom' or
+   `changequote'.  */
 
 /**
  * changesyntax(SYNTAX-SPEC, ...)
@@ -404,7 +403,7 @@ M4BUILTIN_HANDLER (debugfile)
   if (argc == 1)
     m4_debug_set_output (context, NULL);
   else if (!m4_debug_set_output (context, M4ARG (1)))
-    m4_error (context, 0, errno, _("%s: cannot set error file: %s"),
+    m4_error (context, 0, errno, _("%s: cannot set debug file: %s"),
              M4ARG (0), M4ARG (1));
 }