Merge branch 'nd/checkout-option-parsing-fix'

The option parsing of "git checkout" had error checking, dwim and
defaulting missing options, all mixed in the code, and issuing an
appropriate error message with useful context was getting harder.
Reorganize the code and allow giving a proper diagnosis when the
user says "git checkout -b -t foo bar" (e.g. "-t" is not a good name
for a branch).

* nd/checkout-option-parsing-fix:
checkout: reorder option handling
checkout: move more parameters to struct checkout_opts
checkout: pass "struct checkout_opts *" as const pointer

diff --cc builtin/checkout.c
index d287ee6e4838603ae6f3f389431a4455099e1008,b4030121c8e1ccd50c4049184ef7764e141f1cfd..781295b2c9abf033481bc135ca1d2330ca489937
--- 1/builtin/checkout.c
--- 2/builtin/checkout.c
+++ b/builtin/checkout.c
@@@ -926,35 -1002,32 +1002,32 @@@ static int checkout_branch(struct check
  int cmd_checkout(int argc, const char **argv, const char *prefix)
  {
        struct checkout_opts opts;
-       unsigned char rev[20];
        struct branch_info new;
-       struct tree *source_tree = NULL;
        char *conflict_style = NULL;
-       int patch_mode = 0;
        int dwim_new_local_branch = 1;
        struct option options[] = {
 -              OPT__QUIET(&opts.quiet, "suppress progress reporting"),
 -              OPT_STRING('b', NULL, &opts.new_branch, "branch",
 -                         "create and checkout a new branch"),
 -              OPT_STRING('B', NULL, &opts.new_branch_force, "branch",
 -                         "create/reset and checkout a branch"),
 -              OPT_BOOLEAN('l', NULL, &opts.new_branch_log, "create reflog for new branch"),
 -              OPT_BOOLEAN(0, "detach", &opts.force_detach, "detach the HEAD at named commit"),
 -              OPT_SET_INT('t', "track",  &opts.track, "set upstream info for new branch",
 +              OPT__QUIET(&opts.quiet, N_("suppress progress reporting")),
 +              OPT_STRING('b', NULL, &opts.new_branch, N_("branch"),
 +                         N_("create and checkout a new branch")),
 +              OPT_STRING('B', NULL, &opts.new_branch_force, N_("branch"),
 +                         N_("create/reset and checkout a branch")),
 +              OPT_BOOLEAN('l', NULL, &opts.new_branch_log, N_("create reflog for new branch")),
 +              OPT_BOOLEAN(0, "detach", &opts.force_detach, N_("detach the HEAD at named commit")),
 +              OPT_SET_INT('t', "track",  &opts.track, N_("set upstream info for new branch"),
                        BRANCH_TRACK_EXPLICIT),
 -              OPT_STRING(0, "orphan", &opts.new_orphan_branch, "new branch", "new unparented branch"),
 -              OPT_SET_INT('2', "ours", &opts.writeout_stage, "checkout our version for unmerged files",
 +              OPT_STRING(0, "orphan", &opts.new_orphan_branch, N_("new branch"), N_("new unparented branch")),
 +              OPT_SET_INT('2', "ours", &opts.writeout_stage, N_("checkout our version for unmerged files"),
                            2),
 -              OPT_SET_INT('3', "theirs", &opts.writeout_stage, "checkout their version for unmerged files",
 +              OPT_SET_INT('3', "theirs", &opts.writeout_stage, N_("checkout their version for unmerged files"),
                            3),
 -              OPT__FORCE(&opts.force, "force checkout (throw away local modifications)"),
 -              OPT_BOOLEAN('m', "merge", &opts.merge, "perform a 3-way merge with the new branch"),
 -              OPT_BOOLEAN(0, "overwrite-ignore", &opts.overwrite_ignore, "update ignored files (default)"),
 -              OPT_STRING(0, "conflict", &conflict_style, "style",
 -                         "conflict style (merge or diff3)"),
 -              OPT_BOOLEAN('p', "patch", &opts.patch_mode, "select hunks interactively"),
 +              OPT__FORCE(&opts.force, N_("force checkout (throw away local modifications)")),
 +              OPT_BOOLEAN('m', "merge", &opts.merge, N_("perform a 3-way merge with the new branch")),
 +              OPT_BOOLEAN(0, "overwrite-ignore", &opts.overwrite_ignore, N_("update ignored files (default)")),
 +              OPT_STRING(0, "conflict", &conflict_style, N_("style"),
 +                         N_("conflict style (merge or diff3)")),
-               OPT_BOOLEAN('p', "patch", &patch_mode, N_("select hunks interactively")),
++              OPT_BOOLEAN('p', "patch", &opts.patch_mode, N_("select hunks interactively")),
                { OPTION_BOOLEAN, 0, "guess", &dwim_new_local_branch, NULL,
 -                "second guess 'git checkout no-such-branch'",
 +                N_("second guess 'git checkout no-such-branch'"),
                  PARSE_OPT_NOARG | PARSE_OPT_HIDDEN },
                OPT_END(),
        };