From 9d484b92ed38c2222b6880e0bc2b572fdc837dbd Mon Sep 17 00:00:00 2001 From: Junio C Hamano Date: Fri, 5 May 2023 09:59:52 -0700 Subject: [PATCH] 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 "--" 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 "--" option. This is the problem Sergey observed. (2) After setting NO_OUTPUT with "-s", code to process "--" 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 --- Documentation/diff-options.txt | 7 +++++-- diff.c | 24 +++++++++++++----------- t/t4000-diff-format.sh | 34 +++++++++++++++++++++++++++++++++- 3 files changed, 51 insertions(+), 14 deletions(-) diff --git a/Documentation/diff-options.txt b/Documentation/diff-options.txt index 3674ac48e92..7d5bb65a49d 100644 --- a/Documentation/diff-options.txt +++ b/Documentation/diff-options.txt @@ -29,8 +29,11 @@ endif::git-diff[] -s:: --no-patch:: - Suppress diff output. Useful for commands like `git show` that - show the patch by default, or to cancel the effect of `--patch`. + Suppress all output from the diff machinery. Useful for + commands like `git show` that show the patch by default to + squelch their output, or to cancel the effect of options like + `--patch`, `--stat` earlier on the command line in an alias. + endif::git-format-patch[] ifdef::git-log[] diff --git a/diff.c b/diff.c index d52db685f70..211ac53814f 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 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_("..."), 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), diff --git a/t/t4000-diff-format.sh b/t/t4000-diff-format.sh index bfcaae390f3..8d50331b8c8 100755 --- a/t/t4000-diff-format.sh +++ b/t/t4000-diff-format.sh @@ -5,6 +5,9 @@ test_description='Test built-in diff output engine. +We happen to know that all diff plumbing and diff Porcelain share the +same command line parser, so testing one should be sufficient; pick +diff-files as a representative. ' TEST_PASSES_SANITIZE_LEAK=true @@ -16,9 +19,11 @@ Line 2 line 3' cat path0 >path1 chmod +x path1 +mkdir path2 +>path2/path3 test_expect_success 'update-index --add two files with and without +x.' ' - git update-index --add path0 path1 + git update-index --add path0 path1 path2/path3 ' mv path0 path0- @@ -91,4 +96,31 @@ test_expect_success 'git diff-files --patch --no-patch does not show the patch' test_must_be_empty err ' + +# Smudge path2/path3 so that dirstat has something to show +date >path2/path3 + +for format in stat raw numstat shortstat summary \ + dirstat cumulative dirstat-by-file \ + patch-with-raw patch-with-stat compact-summary +do + test_expect_success "--no-patch in 'git diff-files --no-patch --$format' is a no-op" ' + git diff-files --no-patch "--$format" >actual && + git diff-files "--$format" >expect && + test_cmp expect actual + ' + + test_expect_success "--no-patch clears all previous ones" ' + git diff-files --$format -s -p >actual && + git diff-files -p >expect && + test_cmp expect actual + ' + + test_expect_success "--no-patch in 'git diff --no-patch --$format' is a no-op" ' + git diff --no-patch "--$format" >actual && + git diff "--$format" >expect && + test_cmp expect actual + ' +done + test_done