Merge branch 'en/removing-untracked-fixes'

Various fixes in code paths that move untracked files away to make room.

* en/removing-untracked-fixes:
  Documentation: call out commands that nuke untracked files/directories
  Comment important codepaths regarding nuking untracked files/dirs
  unpack-trees: avoid nuking untracked dir in way of locally deleted file
  unpack-trees: avoid nuking untracked dir in way of unmerged file
  Change unpack_trees' 'reset' flag into an enum
  Remove ignored files by default when they are in the way
  unpack-trees: make dir an internal-only struct
  unpack-trees: introduce preserve_ignored to unpack_trees_options
  read-tree, merge-recursive: overwrite ignored files by default
  checkout, read-tree: fix leak of unpack_trees_options.dir
  t2500: add various tests for nuking untracked files

Author: gitster

Documentation/git-checkout.txt

@@ -118,8 +118,9 @@ OPTIONS
 -f::
 --force::
 	When switching branches, proceed even if the index or the
-	working tree differs from `HEAD`.  This is used to throw away
-	local changes.
+	working tree differs from `HEAD`, and even if there are untracked
+	files in the way.  This is used to throw away local changes and
+	any untracked files or directories that are in the way.
 +
 When checking out paths from the index, do not fail upon unmerged
 entries; instead, unmerged entries are ignored.

Documentation/git-read-tree.txt

@@ -10,8 +10,7 @@ SYNOPSIS
 --------
 [verse]
 'git read-tree' [[-m [--trivial] [--aggressive] | --reset | --prefix=<prefix>]
-		[-u [--exclude-per-directory=<gitignore>] | -i]]
-		[--index-output=<file>] [--no-sparse-checkout]
+		[-u | -i]] [--index-output=<file>] [--no-sparse-checkout]
 		(--empty | <tree-ish1> [<tree-ish2> [<tree-ish3>]])
 
 
@@ -39,8 +38,9 @@ OPTIONS
 
 --reset::
 	Same as -m, except that unmerged entries are discarded instead
-	of failing. When used with `-u`, updates leading to loss of
-	working tree changes will not abort the operation.
+	of failing.  When used with `-u`, updates leading to loss of
+	working tree changes or untracked files or directories will not
+	abort the operation.
 
 -u::
 	After a successful merge, update the files in the work
@@ -88,21 +88,6 @@ OPTIONS
 	The command will refuse to overwrite entries that already
 	existed in the original index file.
 
---exclude-per-directory=<gitignore>::
-	When running the command with `-u` and `-m` options, the
-	merge result may need to overwrite paths that are not
-	tracked in the current branch.  The command usually
-	refuses to proceed with the merge to avoid losing such a
-	path.  However this safety valve sometimes gets in the
-	way.  For example, it often happens that the other
-	branch added a file that used to be a generated file in
-	your branch, and the safety valve triggers when you try
-	to switch to that branch after you ran `make` but before
-	running `make clean` to remove the generated file.  This
-	option tells the command to read per-directory exclude
-	file (usually '.gitignore') and allows such an untracked
-	but explicitly ignored file to be overwritten.
-
 --index-output=<file>::
 	Instead of writing the results out to `$GIT_INDEX_FILE`,
 	write the resulting index in the named file.  While the

Documentation/git-reset.txt

@@ -69,7 +69,8 @@ linkgit:git-add[1]).
 
 --hard::
 	Resets the index and working tree. Any changes to tracked files in the
-	working tree since `<commit>` are discarded.
+	working tree since `<commit>` are discarded.  Any untracked files or
+	directories in the way of writing any tracked files are simply deleted.
 
 --merge::
 	Resets the index and updates the files in the working tree that are

builtin/am.c

@@ -1917,7 +1917,8 @@ static int fast_forward_to(struct tree *head, struct tree *remote, int reset)
 	opts.dst_index = &the_index;
 	opts.update = 1;
 	opts.merge = 1;
-	opts.reset = reset;
+	opts.reset = reset ? UNPACK_RESET_PROTECT_UNTRACKED : 0;
+	opts.preserve_ignored = 0; /* FIXME: !overwrite_ignore */
 	opts.fn = twoway_merge;
 	init_tree_desc(&t[0], head->buffer, head->size);
 	init_tree_desc(&t[1], remote->buffer, remote->size);

builtin/checkout.c

@@ -646,7 +646,9 @@ static int reset_tree(struct tree *tree, const struct checkout_opts *o,
 	opts.head_idx = -1;
 	opts.update = worktree;
 	opts.skip_unmerged = !worktree;
-	opts.reset = 1;
+	opts.reset = o->force ? UNPACK_RESET_OVERWRITE_UNTRACKED :
+				UNPACK_RESET_PROTECT_UNTRACKED;
+	opts.preserve_ignored = (!o->force && !o->overwrite_ignore);
 	opts.merge = 1;
 	opts.fn = oneway_merge;
 	opts.verbose_update = o->show_progress;
@@ -746,11 +748,7 @@ static int merge_working_tree(const struct checkout_opts *opts,
 				       new_branch_info->commit ?
 				       &new_branch_info->commit->object.oid :
 				       &new_branch_info->oid, NULL);
-		if (opts->overwrite_ignore) {
-			topts.dir = xcalloc(1, sizeof(*topts.dir));
-			topts.dir->flags |= DIR_SHOW_IGNORED;
-			setup_standard_excludes(topts.dir);
-		}
+		topts.preserve_ignored = !opts->overwrite_ignore;
 		tree = parse_tree_indirect(old_branch_info->commit ?
 					   &old_branch_info->commit->object.oid :
 					   the_hash_algo->empty_tree);

builtin/clone.c

@@ -687,6 +687,7 @@ static int checkout(int submodule_progress)
 	opts.update = 1;
 	opts.merge = 1;
 	opts.clone = 1;
+	opts.preserve_ignored = 0;
 	opts.fn = oneway_merge;
 	opts.verbose_update = (option_verbosity >= 0);
 	opts.src_index = &the_index;

builtin/merge.c

@@ -680,6 +680,7 @@ static int read_tree_trivial(struct object_id *common, struct object_id *head,
 	opts.verbose_update = 1;
 	opts.trivial_merges_only = 1;
 	opts.merge = 1;
+	opts.preserve_ignored = 0; /* FIXME: !overwrite_ignore */
 	trees[nr_trees] = parse_tree_indirect(common);
 	if (!trees[nr_trees++])
 		return -1;

builtin/read-tree.c

@@ -38,7 +38,7 @@ static int list_tree(struct object_id *oid)
 }
 
 static const char * const read_tree_usage[] = {
-	N_("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>]])"),
+	N_("git read-tree [(-m [--trivial] [--aggressive] | --reset | --prefix=<prefix>) [-u | -i]] [--no-sparse-checkout] [--index-output=<file>] (--empty | <tree-ish1> [<tree-ish2> [<tree-ish3>]])"),
 	NULL
 };
 
@@ -53,24 +53,16 @@ static int index_output_cb(const struct option *opt, const char *arg,
 static int exclude_per_directory_cb(const struct option *opt, const char *arg,
 				    int unset)
 {
-	struct dir_struct *dir;
 	struct unpack_trees_options *opts;
 
 	BUG_ON_OPT_NEG(unset);
 
 	opts = (struct unpack_trees_options *)opt->value;
 
-	if (opts->dir)
-		die("more than one --exclude-per-directory given.");
-
-	dir = xcalloc(1, sizeof(*opts->dir));
-	dir->flags |= DIR_SHOW_IGNORED;
-	dir->exclude_per_dir = arg;
-	opts->dir = dir;
-	/* We do not need to nor want to do read-directory
-	 * here; we are merely interested in reusing the
-	 * per directory ignore stack mechanism.
-	 */
+	if (!opts->update)
+		die("--exclude-per-directory is meaningless unless -u");
+	if (strcmp(arg, ".gitignore"))
+		die("--exclude-per-directory argument must be .gitignore");
 	return 0;
 }
 
@@ -174,6 +166,9 @@ int cmd_read_tree(int argc, const char **argv, const char *cmd_prefix)
 	if (1 < opts.merge + opts.reset + prefix_set)
 		die("Which one? -m, --reset, or --prefix?");
 
+	if (opts.reset)
+		opts.reset = UNPACK_RESET_OVERWRITE_UNTRACKED;
+
 	/*
 	 * NEEDSWORK
 	 *
@@ -209,8 +204,9 @@ int cmd_read_tree(int argc, const char **argv, const char *cmd_prefix)
 	if ((opts.update || opts.index_only) && !opts.merge)
 		die("%s is meaningless without -m, --reset, or --prefix",
 		    opts.update ? "-u" : "-i");
-	if ((opts.dir && !opts.update))
-		die("--exclude-per-directory is meaningless unless -u");
+	if (opts.update && !opts.reset)
+		opts.preserve_ignored = 0;
+	/* otherwise, opts.preserve_ignored is irrelevant */
 	if (opts.merge && !opts.index_only)
 		setup_work_tree();
 

builtin/reset.c

@@ -67,12 +67,18 @@ static int reset_index(const char *ref, const struct object_id *oid, int reset_t
 	case KEEP:
 	case MERGE:
 		opts.update = 1;
+		opts.preserve_ignored = 0; /* FIXME: !overwrite_ignore */
 		break;
 	case HARD:
 		opts.update = 1;
-		/* fallthrough */
+		opts.reset = UNPACK_RESET_OVERWRITE_UNTRACKED;
+		break;
+	case MIXED:
+		opts.reset = UNPACK_RESET_PROTECT_UNTRACKED;
+		/* but opts.update=0, so working tree not updated */
+		break;
 	default:
-		opts.reset = 1;
+		BUG("invalid reset_type passed to reset_index");
 	}
 
 	read_cache_unmerged();

builtin/stash.c

@@ -256,8 +256,10 @@ static int reset_tree(struct object_id *i_tree, int update, int reset)
 	opts.src_index = &the_index;
 	opts.dst_index = &the_index;
 	opts.merge = 1;
-	opts.reset = reset;
+	opts.reset = reset ? UNPACK_RESET_PROTECT_UNTRACKED : 0;
 	opts.update = update;
+	if (update)
+		opts.preserve_ignored = 0; /* FIXME: !overwrite_ignore */
 	opts.fn = oneway_merge;
 
 	if (unpack_trees(nr_trees, t, &opts))
@@ -1533,6 +1535,7 @@ static int do_push_stash(const struct pathspec *ps, const char *stash_msg, int q
 		} else {
 			struct child_process cp = CHILD_PROCESS_INIT;
 			cp.git_cmd = 1;
+			/* BUG: this nukes untracked files in the way */
 			strvec_pushl(&cp.args, "reset", "--hard", "-q",
 				     "--no-recurse-submodules", NULL);
 			if (run_command(&cp)) {