read-tree: deprecate syntax without tree-ish args

Currently, read-tree can be run without tree-ish arguments, in which
case it will empty the index. Since this behavior is undocumented and
perhaps a bit too invasive to be the "default" action for read-tree,
deprecate it in favor of a new --empty option that does the same thing.

Signed-off-by: Jan Krüger <jk@jk.gs>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/git-read-tree.txt b/Documentation/git-read-tree.txt
index 2e78da448f30ad260cb7683a5610f424d0c5ffea..e88e9c2d55d19844ca56bc2d5b7b683e329b6fb8 100644 (file)
--- a/Documentation/git-read-tree.txt
+++ b/Documentation/git-read-tree.txt
@@ -11,7 +11,7 @@ SYNOPSIS
 'git read-tree' [[-m [--trivial] [--aggressive] | --reset | --prefix=<prefix>]
                [-u [--exclude-per-directory=<gitignore>] | -i]]
                [--index-output=<file>] [--no-sparse-checkout]
-               <tree-ish1> [<tree-ish2> [<tree-ish3>]]
+               (--empty | <tree-ish1> [<tree-ish2> [<tree-ish3>]])
 
 
 DESCRIPTION
@@ -114,6 +114,10 @@ OPTIONS
        Disable sparse checkout support even if `core.sparseCheckout`
        is true.
 
+--empty::
+       Instead of reading tree object(s) into the index, just empty
+       it.
+
 <tree-ish#>::
        The id of the tree object(s) to be read/merged.
 

diff --git a/builtin/read-tree.c b/builtin/read-tree.c
index 9ad1e66916545dd2aeeb110661e56edfa5921019..eb1e3e7467ac722f4b6cc1da03f7671d21abc676 100644 (file)
--- a/builtin/read-tree.c
+++ b/builtin/read-tree.c
@@ -16,6 +16,7 @@
 #include "resolve-undo.h"
 
 static int nr_trees;
+static int read_empty;
 static struct tree *trees[MAX_UNPACK_TREES];
 
 static int list_tree(unsigned char *sha1)
@@ -32,7 +33,7 @@ static int list_tree(unsigned char *sha1)
 }
 
 static const char * const read_tree_usage[] = {
-       "git read-tree [[-m [--trivial] [--aggressive] | --reset | --prefix=<prefix>] [-u [--exclude-per-directory=<gitignore>] | -i]] [--no-sparse-checkout] [--index-output=<file>] <tree-ish1> [<tree-ish2> [<tree-ish3>]]",
+       "git read-tree [[-m [--trivial] [--aggressive] | --reset | --prefix=<prefix>] [-u [--exclude-per-directory=<gitignore>] | -i]] [--no-sparse-checkout] [--index-output=<file>] (--empty | <tree-ish1> [<tree-ish2> [<tree-ish3>]])",
        NULL
 };
 
@@ -106,6 +107,8 @@ int cmd_read_tree(int argc, const char **argv, const char *unused_prefix)
                { OPTION_CALLBACK, 0, "index-output", NULL, "FILE",
                  "write resulting index to <FILE>",
                  PARSE_OPT_NONEG, index_output_cb },
+               OPT_SET_INT(0, "empty", &read_empty,
+                           "only empty the index", 1),
                OPT__VERBOSE(&opts.verbose_update),
                OPT_GROUP("Merging"),
                OPT_SET_INT('m', NULL, &opts.merge,
@@ -166,6 +169,11 @@ int cmd_read_tree(int argc, const char **argv, const char *unused_prefix)
                        die("failed to unpack tree object %s", arg);
                stage++;
        }
+       if (nr_trees == 0 && !read_empty)
+               warning("read-tree: emptying the index with no arguments is deprecated; use --empty");
+       else if (nr_trees > 0 && read_empty)
+               die("passing trees as arguments contradicts --empty");
+
        if (1 < opts.index_only + opts.update)
                die("-u and -i at the same time makes no sense");
        if ((opts.update||opts.index_only) && !opts.merge)