Merge branch 'sb/checkout-explit-detach-no-advice'

"git checkout --detach <branch>" used to give the same advice
message as that is issued when "git checkout <tag>" (or anything
that is not a branch name) is given, but asking with "--detach" is
an explicit enough sign that the user knows what is going on.  The
advice message has been squelched in this case.

* sb/checkout-explit-detach-no-advice:
checkout: do not mention detach advice for explicit --detach option

diff --combined builtin/checkout.c
index 48661115226b32ed6e98477ee49eea1278685def,91bafdaef4295eaf5d241020a21432f58985a460..8672d0724ffec4bc0a74ba2c60d3a4dd0f504a21
--- 1/builtin/checkout.c
--- 2/builtin/checkout.c
+++ b/builtin/checkout.c
@@@ -276,7 -276,7 +276,7 @@@ static int checkout_paths(const struct 
  
        hold_locked_index(lock_file, 1);
        if (read_cache_preload(&opts->pathspec) < 0)
 -              return error(_("corrupt index file"));
 +              return error(_("index file corrupt"));
  
        if (opts->source_tree)
                read_tree_some(opts->source_tree, &opts->pathspec);
@@@ -470,7 -470,7 +470,7 @@@ static int merge_working_tree(const str
  
        hold_locked_index(lock_file, 1);
        if (read_cache_preload(NULL) < 0)
 -              return error(_("corrupt index file"));
 +              return error(_("index file corrupt"));
  
        resolve_undo_clear();
        if (opts->force) {
@@@ -567,13 -567,10 +567,13 @@@
                        o.ancestor = old->name;
                        o.branch1 = new->name;
                        o.branch2 = "local";
 -                      merge_trees(&o, new->commit->tree, work,
 +                      ret = merge_trees(&o, new->commit->tree, work,
                                old->commit->tree, &result);
 +                      if (ret < 0)
 +                              exit(128);
                        ret = reset_tree(new->commit->tree, opts, 0,
                                         writeout_error);
 +                      strbuf_release(&o.obuf);
                        if (ret)
                                return ret;
                }
@@@ -658,7 -655,8 +658,8 @@@ static void update_refs_for_switch(cons
                update_ref(msg.buf, "HEAD", new->commit->object.oid.hash, NULL,
                           REF_NODEREF, UPDATE_REFS_DIE_ON_ERR);
                if (!opts->quiet) {
-                       if (old->path && advice_detached_head)
+                       if (old->path &&
+                           advice_detached_head && !opts->force_detach)
                                detach_advice(new->name);
                        describe_detached_head(_("HEAD is now at"), new->commit);
                }
@@@ -706,7 -704,8 +707,7 @@@ static int add_pending_uninteresting_re
  static void describe_one_orphan(struct strbuf *sb, struct commit *commit)
  {
        strbuf_addstr(sb, "  ");
 -      strbuf_addstr(sb,
 -              find_unique_abbrev(commit->object.oid.hash, DEFAULT_ABBREV));
 +      strbuf_add_unique_abbrev(sb, commit->object.oid.hash, DEFAULT_ABBREV);
        strbuf_addch(sb, ' ');
        if (!parse_commit(commit))
                pp_commit_easy(CMIT_FMT_ONELINE, commit, sb);
@@@ -1140,7 -1139,7 +1141,7 @@@ int cmd_checkout(int argc, const char *
                OPT_STRING('B', NULL, &opts.new_branch_force, N_("branch"),
                           N_("create/reset and checkout a branch")),
                OPT_BOOL('l', NULL, &opts.new_branch_log, N_("create reflog for new branch")),
 -              OPT_BOOL(0, "detach", &opts.force_detach, N_("detach the HEAD at named commit")),
 +              OPT_BOOL(0, "detach", &opts.force_detach, N_("detach 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, N_("new-branch"), N_("new unparented branch")),