[PATCH] fix POSIX 'command -pv'

[Martijn Dekker]

I found another minor POSIX bug in mksh 'command': the options -p and -v
don't combine correctly.

The -p flag means that 'command' will search the system default PATH
instead of the current PATH, but does not change that builtins take
precedence over external commands. Hence 'command -p test' will execute
the 'test' builtin and not /bin/test.

'-v' output should reflect what would actually be executed without that
flag. Without the -p flag, this works fine:
$ command -v true
true

However, command -pv always shows the external command, even if command
-p does not execute it:

$ command -pv [
/bin/[
(expected output: '[')

$ command -p [
mksh: [: missing ]
^^^^ it's the builtin, as expected

This also means that 'command -pv' should find shell keywords such as
'if' the same way 'command -v' should (as is the behaviour on ksh93,
bash, dash, etc.), so my earlier patch for 'command' of 1 July also
needs to be amended.

$ command -pv if
(nothing, expected output: if)

I believe the following patch fixes it (without affecting 'whence -p').

Thanks,

- M.

diff -ur mksh.orig/funcs.c mksh/funcs.c
--- mksh.orig/funcs.c   2016-01-20 22:34:37.000000000 +0100
+++ mksh/funcs.c        2016-02-14 23:27:54.000000000 +0100
@@ -548,15 +548,14 @@
                 * or whence -pv. This should be considered a feature.
                 */
                vflag = Vflag;
-       }
-       if (pflag)
+       } else if (pflag)
                fcflags &= ~(FC_BI | FC_FUNC);

        while ((vflag || rv == 0) && (id = *wp++) != NULL) {
                uint32_t h = 0;

                tp = NULL;
-               if (!pflag)
+               if (!iam_whence || !pflag)
                        tp = ktsearch(&keywords, id, h = hash(id));
                if (!tp && !pflag) {
                        tp = ktsearch(&aliases, id, h ? h : hash(id));