Merge branch 'cc/fast-import-usage' into seen

The usage string of 'git fast-import' has been updated to use the
parse_options() API for displaying help, and its SYNOPSIS in the
documentation has been standardized to match.

* cc/fast-import-usage:
  fast-import: remove useless from_stream argument
  fast-import: use parse_options() for command line options
  fast-import: use callbacks to parse some options
  fast-import: use struct option for usage string
  fast-import: move command state globals into 'struct fast_import_state'
  fast-import: introduce 'struct fast_import_state'
  fast-import: factor out option_*() functions
  fast-import: use int for some bool flags
  fast-import: localize 'i' into the 'for' loops using it
  api-parse-options.adoc: document hidden and OPT_*_F option macros
  api-parse-options.adoc: document per-option flags
  parse-options: introduce OPT_HIDDEN_GROUP

Documentation/git-fast-import.adoc

@@ -9,7 +9,7 @@ git-fast-import - Backend for fast Git data importers
 SYNOPSIS
 --------
 [verse]
-frontend | 'git fast-import' [<options>]
+'git fast-import' [<options>]
 
 DESCRIPTION
 -----------

Documentation/technical/api-parse-options.adoc

@@ -150,8 +150,76 @@ Data Structure
 
 The main data structure is an array of the `option` struct,
 say `static struct option builtin_add_options[]`.
+
+Option flags
+~~~~~~~~~~~~
+
+Each option can carry flags in the `flags` field of its `option`
+struct. These are per-option flags and are distinct from the
+`parse_options()` flags described above; they are usually set through
+the `OPT_*_F()` macro variants (see below) rather than by hand. They
+are the bitwise-or of:
+
+`PARSE_OPT_OPTARG`::
+	The option's argument is optional, i.e. both `--option` and
+	`--option=<value>` are accepted.
+
+`PARSE_OPT_NOARG`::
+	The option takes no argument at all. Using `--option=<value>`
+	is rejected.
+
+`PARSE_OPT_NONEG`::
+	Disable the automatically generated negated `--no-option`
+	form.
+
+`PARSE_OPT_HIDDEN`::
+	Hide the option: it is omitted from the usage shown by
+	`git <cmd> -h`, but is still shown by `git <cmd> --help-all`.
+	The option is parsed as usual either way. This is meant for
+	deprecated, advanced or otherwise uncommon options.
+
+`PARSE_OPT_LASTARG_DEFAULT`::
+	Use the default value (`defval`) when the option is used
+	without an argument, even for an option that normally requires
+	one. Only the last argument on the command line takes effect.
+
+`PARSE_OPT_NODASH`::
+	The option is a single character without a leading dash, such
+	as the `+` used by some commands.
+
+`PARSE_OPT_LITERAL_ARGHELP`::
+	Use the argument help string (`argh`) verbatim in the usage
+	output instead of surrounding it with `<>` or `[]`. Useful when
+	`argh` already contains a hand-formatted description.
+
+`PARSE_OPT_FROM_ALIAS`::
+	Internal flag, set on options that were expanded from a
+	configured alias. It should not be set by callers.
+
+`PARSE_OPT_NOCOMPLETE`::
+	Do not offer this option for completion.
+
+`PARSE_OPT_COMP_ARG`::
+	The option's argument, rather than the option itself, is what
+	should be completed.
+
+`PARSE_OPT_CMDMODE`::
+	The option is one of several mutually exclusive "command mode"
+	options that share the same variable. Using more than one of
+	them at once is rejected.
+
+Macros
+~~~~~~
+
 There are some macros to easily define options:
 
+Many of the macros below have an `_F` variant (for example `OPT_BOOL_F`,
+`OPT_STRING_F`, `OPT_INTEGER_F`, `OPT_SET_INT_F`, `OPT_BIT_F` and
+`OPT_CALLBACK_F`) that takes an additional trailing `flags` argument.
+That argument is the bitwise-or of the per-option flags described in the
+"Option flags" section above; the non-`_F` macros are simply defined
+with `flags` set to `0`.
+
 `OPT__ABBREV(&int_var)`::
 	Add `--abbrev[=<n>]`.
 
@@ -175,10 +243,21 @@ There are some macros to easily define options:
 	describes the group or an empty string.
 	Start the description with an upper-case letter.
 
+`OPT_HIDDEN_GROUP(description)`::
+	Like `OPT_GROUP()`, but the group header carries
+	`PARSE_OPT_HIDDEN`, so it is only shown by `--help-all` and not
+	by `-h`. Use it to label a group that contains only hidden
+	options, which would otherwise show an empty header under `-h`.
+
 `OPT_BOOL(short, long, &int_var, description)`::
 	Introduce a boolean option. `int_var` is set to one with
 	`--option` and set to zero with `--no-option`.
 
+`OPT_HIDDEN_BOOL(short, long, &int_var, description)`::
+	Like `OPT_BOOL()`, but the option carries `PARSE_OPT_HIDDEN`,
+	so it is hidden from `-h` while still being shown by
+	`--help-all`.
+
 `OPT_COUNTUP(short, long, &int_var, description)`::
 	Introduce a count-up option.
 	Each use of `--option` increments `int_var`, starting from zero

parse-options.c

@@ -1414,6 +1414,8 @@ static enum parse_opt_result usage_with_options_internal(struct parse_opt_ctx_t
 
 		if (opts->type == OPTION_SUBCOMMAND)
 			continue;
+		if (!full && (opts->flags & PARSE_OPT_HIDDEN))
+			continue;
 		if (opts->type == OPTION_GROUP) {
 			fputc('\n', outfile);
 			need_newline = 0;
@@ -1421,8 +1423,6 @@ static enum parse_opt_result usage_with_options_internal(struct parse_opt_ctx_t
 				fprintf(outfile, "%s\n", _(opts->help));
 			continue;
 		}
-		if (!full && (opts->flags & PARSE_OPT_HIDDEN))
-			continue;
 
 		if (need_newline) {
 			fputc('\n', outfile);

parse-options.h

@@ -237,6 +237,11 @@ struct option {
 	.type = OPTION_GROUP, \
 	.help = (h), \
 }
+#define OPT_HIDDEN_GROUP(h) { \
+	.type = OPTION_GROUP, \
+	.help = (h), \
+	.flags = PARSE_OPT_HIDDEN, \
+}
 #define OPT_BIT(s, l, v, h, b)      OPT_BIT_F(s, l, v, h, b, 0)
 #define OPT_BITOP(s, l, v, h, set, clear) { \
 	.type = OPTION_BITOP, \

t/helper/test-parse-options.c

@@ -209,6 +209,10 @@ int cmd__parse_options(int argc, const char **argv)
 		OPT_GROUP("Alias"),
 		OPT_STRING('A', "alias-source", &string, "string", "get a string"),
 		OPT_ALIAS('Z', "alias-target", "alias-source"),
+		OPT_HIDDEN_GROUP("Hidden options"),
+		OPT_HIDDEN_BOOL(0, "hidden-bool", &boolean, "get a boolean"),
+		OPT_INTEGER_F('k', "hidden-integer", &integer, "get a integer",
+			      PARSE_OPT_HIDDEN),
 		OPT_END(),
 	};
 	int ret = 0;

t/t0040-parse-options.sh

@@ -7,7 +7,7 @@ test_description='our own option parser'
 
 . ./test-lib.sh
 
-cat >expect <<\EOF
+cat >expect-part1 <<\EOF
 usage: test-tool parse-options <options>
 
     A helper function for the parse-options API.
@@ -41,6 +41,9 @@ String options
     --[no-]string2 <str>  get another string
     --[no-]st <st>        get another string (pervert ordering)
     -o <str>              get another string
+EOF
+
+cat >expect-part2 <<\EOF
     --longhelp            help text of this entry
                           spans multiple lines
     --[no-]list <str>     add str to list
@@ -67,12 +70,32 @@ Alias
 
 EOF
 
+cat >expect-noop <<\EOF
+    --[no-]obsolete       no-op (backward compatibility)
+EOF
+
+cat >expect-hidden <<\EOF
+Hidden options
+    --[no-]hidden-bool    get a boolean
+    -k, --[no-]hidden-integer <n>
+                          get a integer
+
+EOF
+
 test_expect_success 'test help' '
+	cat expect-part1 expect-part2 >expect &&
 	test-tool parse-options -h >output 2>output.err &&
 	test_must_be_empty output.err &&
 	test_cmp expect output
 '
 
+test_expect_success 'test --help-all shows hidden group and options' '
+	cat expect-part1 expect-noop expect-part2 expect-hidden >expect-help-all &&
+	test-tool parse-options --help-all >output 2>output.err &&
+	test_must_be_empty output.err &&
+	test_cmp expect-help-all output
+'
+
 mv expect expect.err
 
 check () {

t/t0450/adoc-help-mismatches

@@ -12,7 +12,6 @@ column
 credential
 credential-cache
 credential-store
-fast-import
 fetch-pack
 fmt-merge-msg
 format-patch

t/t9300-fast-import.sh

@@ -2827,6 +2827,13 @@ test_expect_success 'R: unknown commandline options are rejected' '\
 	test_must_fail git fast-import --non-existing-option < /dev/null
 '
 
+test_expect_success 'R: feature-only names are rejected on the command line' '
+	for opt in --alias --get-mark --ls --notes
+	do
+		test_must_fail git fast-import "$opt" </dev/null || return 1
+	done
+'
+
 test_expect_success 'R: die on invalid option argument' '
 	echo "option git active-branches=-5" |
 	test_must_fail git fast-import &&