diff: fix interaction between the "-s" option and other options
Sergey Organov noticed and reported "--patch --no-patch --raw"
behaves differently from just "--raw". It turns out that there are
a few interesting bugs in the implementation and documentation.
* First, the documentation for "--no-patch" was unclear that it
could be read to mean "--no-patch" countermands an earlier
"--patch" but not other things. The intention of "--no-patch"
ever since it was introduced at d09cd15d (diff: allow --no-patch
as synonym for -s, 2013-07-16) was to serve as a synonym for
"-s", so "--raw --patch --no-patch" should have produced no
output, but it can be (mis)read to allow showing only "--raw"
output.
* Then the interaction between "-s" and other format options were
poorly implemented. Modern versions of Git uses one bit each to
represent formatting options like "--patch", "--stat" in a single
output_format word, but for historical reasons, "-s" also is
represented as another bit in the same word. This allows two
interesting bugs to happen, and we have both X-<.
(1) After setting a format bit, then setting NO_OUTPUT with "-s",
the code to process another "--<format>" option drops the
NO_OUTPUT bit to allow output to be shown again. However,
the code to handle "-s" only set NO_OUTPUT without unsetting
format bits set earlier, so the earlier format bit got
revealed upon seeing the second "--<format>" option. This is
the problem Sergey observed.
(2) After setting NO_OUTPUT with "-s", code to process
"--<format>" option can forget to unset NO_OUTPUT, leaving
the command still silent.
It is tempting to change the meaning of "--no-patch" to mean
"disable only the patch format output" and reimplement "-s" as "not
showing anything", but it would be an end-user visible change in
behavior. Let's fix the interactions of these bits to first make
"-s" work as intended.
The fix is conceptually very simple.
* Whenever we set DIFF_FORMAT_FOO because we saw the "--foo"
option (e.g. DIFF_FORMAT_RAW is set when the "--raw" option is
given), we make sure we drop DIFF_FORMAT_NO_OUTPUT. We forgot to
do so in some of the options and caused (2) above.
* When processing "-s" option, we should not just set
DIFF_FORMAT_NO_OUTPUT bit, but clear other DIFF_FORMAT_* bits.
We didn't do so and retained format bits set by options
previously seen, causing (1) above.
It is even more tempting to lose NO_OUTPUT bit and instead take
output_format word being 0 as its replacement, but that would break
the mechanism "git show" uses to default to "--patch" output, where
the distinction between telling the command to be silent with "-s"
and having no output format specified on the command line matters,
and an explicit output format given on the command line should not
be "combined" with the default "--patch" format.
So, while we cannot lose the NO_OUTPUT bit, as a follow-up work, we
may want to replace it with OPTION_GIVEN bit, and
* make "--patch", "--raw", etc. set DIFF_FORMAT_$format bit and
DIFF_FORMAT_OPTION_GIVEN bit on for each format. "--no-raw",
etc. will set off DIFF_FORMAT_$format bit but still record the
fact that we saw an option from the command line by setting
DIFF_FORMAT_OPTION_GIVEN bit.
* make "-s" (and its synonym "--no-patch") clear all other bits
and set only the DIFF_FORMAT_OPTION_GIVEN bit on.
which I suspect would make the code much cleaner without breaking
any end-user expectations.
Once that is in place, transitioning "--no-patch" to mean the
counterpart of "--patch", just like "--no-raw" only defeats an
earlier "--raw", would be quite simple at the code level. The
social cost of migrating the end-user expectations might be too
great for it to be worth, but at least the "GIVEN" bit clean-up
alone may be worth it.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/diff.c b/diff.c
index d52db68..211ac53 100644
--- a/diff.c
+++ b/diff.c
@@ -4874,6 +4874,7 @@ static int diff_opt_stat(const struct option *opt, const char *value, int unset)
} else
BUG("%s should not get here", opt->long_name);
+ options->output_format &= ~DIFF_FORMAT_NO_OUTPUT;
options->output_format |= DIFF_FORMAT_DIFFSTAT;
options->stat_name_width = name_width;
options->stat_graph_width = graph_width;
@@ -4893,6 +4894,7 @@ static int parse_dirstat_opt(struct diff_options *options, const char *params)
* The caller knows a dirstat-related option is given from the command
* line; allow it to say "return this_function();"
*/
+ options->output_format &= ~DIFF_FORMAT_NO_OUTPUT;
options->output_format |= DIFF_FORMAT_DIRSTAT;
return 1;
}
@@ -5092,6 +5094,7 @@ static int diff_opt_compact_summary(const struct option *opt,
options->flags.stat_with_summary = 0;
} else {
options->flags.stat_with_summary = 1;
+ options->output_format &= ~DIFF_FORMAT_NO_OUTPUT;
options->output_format |= DIFF_FORMAT_DIFFSTAT;
}
return 0;
@@ -5410,9 +5413,8 @@ static void prep_parse_options(struct diff_options *options)
OPT_BITOP('p', "patch", &options->output_format,
N_("generate patch"),
DIFF_FORMAT_PATCH, DIFF_FORMAT_NO_OUTPUT),
- OPT_BIT_F('s', "no-patch", &options->output_format,
- N_("suppress diff output"),
- DIFF_FORMAT_NO_OUTPUT, PARSE_OPT_NONEG),
+ OPT_SET_INT('s', "no-patch", &options->output_format,
+ N_("suppress diff output"), DIFF_FORMAT_NO_OUTPUT),
OPT_BITOP('u', NULL, &options->output_format,
N_("generate patch"),
DIFF_FORMAT_PATCH, DIFF_FORMAT_NO_OUTPUT),
@@ -5421,9 +5423,9 @@ static void prep_parse_options(struct diff_options *options)
PARSE_OPT_NONEG | PARSE_OPT_OPTARG, diff_opt_unified),
OPT_BOOL('W', "function-context", &options->flags.funccontext,
N_("generate diffs with <n> lines context")),
- OPT_BIT_F(0, "raw", &options->output_format,
+ OPT_BITOP(0, "raw", &options->output_format,
N_("generate the diff in raw format"),
- DIFF_FORMAT_RAW, PARSE_OPT_NONEG),
+ DIFF_FORMAT_RAW, DIFF_FORMAT_NO_OUTPUT),
OPT_BITOP(0, "patch-with-raw", &options->output_format,
N_("synonym for '-p --raw'"),
DIFF_FORMAT_PATCH | DIFF_FORMAT_RAW,
@@ -5432,12 +5434,12 @@ static void prep_parse_options(struct diff_options *options)
N_("synonym for '-p --stat'"),
DIFF_FORMAT_PATCH | DIFF_FORMAT_DIFFSTAT,
DIFF_FORMAT_NO_OUTPUT),
- OPT_BIT_F(0, "numstat", &options->output_format,
+ OPT_BITOP(0, "numstat", &options->output_format,
N_("machine friendly --stat"),
- DIFF_FORMAT_NUMSTAT, PARSE_OPT_NONEG),
- OPT_BIT_F(0, "shortstat", &options->output_format,
+ DIFF_FORMAT_NUMSTAT, DIFF_FORMAT_NO_OUTPUT),
+ OPT_BITOP(0, "shortstat", &options->output_format,
N_("output only the last line of --stat"),
- DIFF_FORMAT_SHORTSTAT, PARSE_OPT_NONEG),
+ DIFF_FORMAT_SHORTSTAT, DIFF_FORMAT_NO_OUTPUT),
OPT_CALLBACK_F('X', "dirstat", options, N_("<param1,param2>..."),
N_("output the distribution of relative amount of changes for each sub-directory"),
PARSE_OPT_NONEG | PARSE_OPT_OPTARG,
@@ -5453,9 +5455,9 @@ static void prep_parse_options(struct diff_options *options)
OPT_BIT_F(0, "check", &options->output_format,
N_("warn if changes introduce conflict markers or whitespace errors"),
DIFF_FORMAT_CHECKDIFF, PARSE_OPT_NONEG),
- OPT_BIT_F(0, "summary", &options->output_format,
+ OPT_BITOP(0, "summary", &options->output_format,
N_("condensed summary such as creations, renames and mode changes"),
- DIFF_FORMAT_SUMMARY, PARSE_OPT_NONEG),
+ DIFF_FORMAT_SUMMARY, DIFF_FORMAT_NO_OUTPUT),
OPT_BIT_F(0, "name-only", &options->output_format,
N_("show only names of changed files"),
DIFF_FORMAT_NAME, PARSE_OPT_NONEG),
