[PATCH v2 1/3] Revert "parse-options: allow keep-unknown + stop-at-non-opt combination"

["Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>]

This reverts commit a85e5a01080e35da0f94bf98f5f334c64e214ce3, which is a
revert of 0d260f9a09 (parseopt: prevent KEEP_UNKNOWN and
STOP_AT_NON_OPTION from being used together - 2009-03-09).

As described in 0d260f9a09, this option combination is tricky to get
right and should be prevented unless you know what you're doing. In the
one-shot mode, the diff and revision parsers are very well aware of
remaining arguments being potentially unknown options or revisions and
should handle the combination safely.

Reinstate the check added by 0d260f9a09. Modify it a bit to let one-shot
mode through.

Noticed-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 parse-options.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/parse-options.c b/parse-options.c
index a0ff8ea225..cec74522e5 100644
--- a/parse-options.c
+++ b/parse-options.c
@@ -466,6 +466,10 @@ void parse_options_start(struct parse_opt_ctx_t *ctx,
 	ctx->prefix = prefix;
 	ctx->cpidx = ((flags & PARSE_OPT_KEEP_ARGV0) != 0);
 	ctx->flags = flags;
+	if ((flags & PARSE_OPT_KEEP_UNKNOWN) &&
+	    (flags & PARSE_OPT_STOP_AT_NON_OPTION) &&
+	    !(flags & PARSE_OPT_ONE_SHOT))
+		BUG("STOP_AT_NON_OPTION and KEEP_UNKNOWN don't go together");
 	if ((flags & PARSE_OPT_ONE_SHOT) &&
 	    (flags & PARSE_OPT_KEEP_ARGV0))
 		BUG("Can't keep argv0 if you don't have it");
-- 
2.20.1.560.g70ca8b83ee