From d012ceb5f3351af0589a0c82b07059bce8c7b24b Mon Sep 17 00:00:00 2001 From: Patrick Steinhardt Date: Thu, 17 Apr 2025 12:49:37 +0200 Subject: global: use designated initializers for options While we expose macros for most of our different option types understood by the "parse-options" subsystem, not every combination of fields that has one as that would otherwise quickly lead to an explosion of macros. Instead, we just initialize structures manually for those variants of fields that don't have a macro. Callsites that open-code these structure initialization don't use designated initializers though and instead just provide values for each of the fields that they want to initialize. This has three significant downsides: - Callsites need to specify all values up to the last field that they care about. This often includes fields that should simply be left at their default zero-initialized state, which adds distraction. - Any reader not deeply familiar with the layout of the structure has a hard time figuring out what the respective initializers mean. - Reordering or introducing new fields in the middle of the structure is impossible without adapting all callsites. Convert all sites to instead use designated initializers, which we have started using in our codebase quite a while ago. This allows us to skip any default-initialized fields, gives the reader context by specifying the field names and allows us to reorder or introduce new fields where we want to. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano --- builtin/grep.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) (limited to 'builtin/grep.c') diff --git a/builtin/grep.c b/builtin/grep.c index d1427290f7..c4869733e1 100644 --- a/builtin/grep.c +++ b/builtin/grep.c @@ -1017,10 +1017,16 @@ int cmd_grep(int argc, OPT_BOOL(0, "all-match", &opt.all_match, N_("show only matches from files that match all patterns")), OPT_GROUP(""), - { OPTION_STRING, 'O', "open-files-in-pager", &show_in_pager, - N_("pager"), N_("show matching files in the pager"), - PARSE_OPT_OPTARG | PARSE_OPT_NOCOMPLETE, - NULL, (intptr_t)default_pager }, + { + .type = OPTION_STRING, + .short_name = 'O', + .long_name = "open-files-in-pager", + .value = &show_in_pager, + .argh = N_("pager"), + .help = N_("show matching files in the pager"), + .flags = PARSE_OPT_OPTARG | PARSE_OPT_NOCOMPLETE, + .defval = (intptr_t)default_pager, + }, OPT_BOOL_F(0, "ext-grep", &external_grep_allowed__ignored, N_("allow calling of grep(1) (ignored by this build)"), PARSE_OPT_NOCOMPLETE), -- cgit 1.2.3-korg From 791aeddfa2fdb9e830e24c50c97bb5e8bf3613e6 Mon Sep 17 00:00:00 2001 From: Patrick Steinhardt Date: Thu, 17 Apr 2025 12:49:42 +0200 Subject: parse-options: detect mismatches in integer signedness MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit It was reported that "t5620-backfill.sh" fails on s390x and sparc64 in a test that exercises the "--min-batch-size" command line option. The symptom was that the option didn't seem to have an effect: we didn't fetch objects with a batch size of 20, but instead fetched all objects at once. As it turns out, the root cause is that `--min-batch-size` uses `OPT_INTEGER()` to parse the command line option. While this macro expects the caller to pass a pointer to an integer, we instead pass a pointer to a `size_t`. This coincidentally works on most platforms, but it breaks apart on the mentioned platforms because they are big endian. This issue isn't specific to git-backfill(1): there are a couple of other places where we have the same type confusion going on. This indicates that the issue really is the interface that the parse-options subsystem provides -- it is simply too easy to get this wrong as there isn't any kind of compiler warning, and things just work on the most common systems. Address the systemic issue by introducing two new build asserts `BARF_UNLESS_SIGNED()` and `BARF_UNLESS_UNSIGNED()`. As the names already hint at, those macros will cause a compiler error when passed a value that is not signed or unsigned, respectively. Adapt `OPT_INTEGER()`, `OPT_UNSIGNED()` as well as `OPT_MAGNITUDE()` to use those asserts. This uncovers a small set of sites where we indeed have the same bug as in git-backfill(1). Adapt all of them to use the correct option. Reported-by: Todd Zullinger Reported-by: John Paul Adrian Glaubitz Helped-by: SZEDER Gábor Helped-by: Jeff King Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano --- apply.c | 4 ++-- builtin/backfill.c | 4 ++-- builtin/column.c | 2 +- builtin/grep.c | 4 ++-- git-compat-util.h | 7 +++++++ parse-options.h | 4 ++-- 6 files changed, 16 insertions(+), 9 deletions(-) (limited to 'builtin/grep.c') diff --git a/apply.c b/apply.c index f274a37948..a850c7d75f 100644 --- a/apply.c +++ b/apply.c @@ -5123,8 +5123,8 @@ int apply_parse_options(int argc, const char **argv, /* Think twice before adding "--nul" synonym to this */ OPT_SET_INT('z', NULL, &state->line_termination, N_("paths are separated with NUL character"), '\0'), - OPT_INTEGER('C', NULL, &state->p_context, - N_("ensure at least lines of context match")), + OPT_UNSIGNED('C', NULL, &state->p_context, + N_("ensure at least lines of context match")), OPT_CALLBACK(0, "whitespace", state, N_("action"), N_("detect new or modified lines that have whitespace errors"), apply_option_parse_whitespace), diff --git a/builtin/backfill.c b/builtin/backfill.c index 33e1ea2f84..d95d7a2d4d 100644 --- a/builtin/backfill.c +++ b/builtin/backfill.c @@ -123,8 +123,8 @@ int cmd_backfill(int argc, const char **argv, const char *prefix, struct reposit .sparse = 0, }; struct option options[] = { - OPT_INTEGER(0, "min-batch-size", &ctx.min_batch_size, - N_("Minimum number of objects to request at a time")), + OPT_UNSIGNED(0, "min-batch-size", &ctx.min_batch_size, + N_("Minimum number of objects to request at a time")), OPT_BOOL(0, "sparse", &ctx.sparse, N_("Restrict the missing objects to the current sparse-checkout")), OPT_END(), diff --git a/builtin/column.c b/builtin/column.c index 50314cc255..ce6443d5fa 100644 --- a/builtin/column.c +++ b/builtin/column.c @@ -31,7 +31,7 @@ int cmd_column(int argc, struct option options[] = { OPT_STRING(0, "command", &real_command, N_("name"), N_("lookup config vars")), OPT_COLUMN(0, "mode", &colopts, N_("layout to use")), - OPT_INTEGER(0, "raw-mode", &colopts, N_("layout to use")), + OPT_UNSIGNED(0, "raw-mode", &colopts, N_("layout to use")), OPT_INTEGER(0, "width", &copts.width, N_("maximum width")), OPT_STRING(0, "indent", &copts.indent, N_("string"), N_("padding space on left border")), OPT_STRING(0, "nl", &copts.nl, N_("string"), N_("padding space on right border")), diff --git a/builtin/grep.c b/builtin/grep.c index c4869733e1..f23a6f1dc8 100644 --- a/builtin/grep.c +++ b/builtin/grep.c @@ -983,9 +983,9 @@ int cmd_grep(int argc, OPT_CALLBACK('C', "context", &opt, N_("n"), N_("show context lines before and after matches"), context_callback), - OPT_INTEGER('B', "before-context", &opt.pre_context, + OPT_UNSIGNED('B', "before-context", &opt.pre_context, N_("show context lines before matches")), - OPT_INTEGER('A', "after-context", &opt.post_context, + OPT_UNSIGNED('A', "after-context", &opt.post_context, N_("show context lines after matches")), OPT_INTEGER(0, "threads", &num_threads, N_("use worker threads")), diff --git a/git-compat-util.h b/git-compat-util.h index cf733b38ac..1218fcf81a 100644 --- a/git-compat-util.h +++ b/git-compat-util.h @@ -110,12 +110,19 @@ DISABLE_WARNING(-Wsign-compare) # define BARF_UNLESS_COPYABLE(dst, src) \ BUILD_ASSERT_OR_ZERO(__builtin_types_compatible_p(__typeof__(*(dst)), \ __typeof__(*(src)))) + +# define BARF_UNLESS_SIGNED(var) BUILD_ASSERT_OR_ZERO(((__typeof__(var)) -1) < 0) +# define BARF_UNLESS_UNSIGNED(var) BUILD_ASSERT_OR_ZERO(((__typeof__(var)) -1) > 0) #else # define BARF_UNLESS_AN_ARRAY(arr) 0 # define BARF_UNLESS_COPYABLE(dst, src) \ BUILD_ASSERT_OR_ZERO(0 ? ((*(dst) = *(src)), 0) : \ sizeof(*(dst)) == sizeof(*(src))) + +# define BARF_UNLESS_SIGNED(var) 0 +# define BARF_UNLESS_UNSIGNED(var) 0 #endif + /* * ARRAY_SIZE - get the number of elements in a visible array * @x: the array whose size you want. diff --git a/parse-options.h b/parse-options.h index dc460a26ff..91c3e3c29b 100644 --- a/parse-options.h +++ b/parse-options.h @@ -218,7 +218,7 @@ struct option { .type = OPTION_INTEGER, \ .short_name = (s), \ .long_name = (l), \ - .value = (v), \ + .value = (v) + BARF_UNLESS_SIGNED(*(v)), \ .precision = sizeof(*v), \ .argh = N_("n"), \ .help = (h), \ @@ -280,7 +280,7 @@ struct option { .type = OPTION_UNSIGNED, \ .short_name = (s), \ .long_name = (l), \ - .value = (v), \ + .value = (v) + BARF_UNLESS_UNSIGNED(*(v)), \ .precision = sizeof(*v), \ .argh = N_("n"), \ .help = (h), \ -- cgit 1.2.3-korg