Merge branch 'nd/precious' into jch

"git clean" learned to pay attention to the 'precious' attributes
and keep untracked paths with the attribute instead of removing
when the "--keep-precious" is given.

Retracted.
cf. <CACsJy8AEZ-Lz6zgEsuNukvphB9TTa9FAC1gK05fhnie2xtfc9w@mail.gmail.com>

I am not sure what aspect of this longer-term "precious" vision,
which gets taught to various commands and use cases individually
and incrementally, Ævar finds problematic, which I understand is
the reason of redtraction.

* nd/precious:
  Introduce "precious" file concept

Author: gitster

Documentation/git-clean.txt

@@ -8,7 +8,7 @@ git-clean - Remove untracked files from the working tree
 SYNOPSIS
 --------
 [verse]
-'git clean' [-d] [-f] [-i] [-n] [-q] [-e <pattern>] [-x | -X] [--] <path>...
+'git clean' [<options>] [-d] [-f] [-i] [-n] [-x | -X] [--] <path>...
 
 DESCRIPTION
 -----------
@@ -70,6 +70,10 @@ OPTIONS
 	Remove only files ignored by Git.  This may be useful to rebuild
 	everything from scratch, but keep manually created files.
 
+--keep-precious::
+	Do not remove untracked or ignored files if they have
+	`precious` attribute.
+
 Interactive mode
 ----------------
 When the command enters the interactive mode, it shows the

Documentation/gitattributes.txt

@@ -1193,6 +1193,17 @@ If this attribute is not set or has an invalid value, the value of the
 (See linkgit:git-config[1]).
 
 
+Precious files
+~~~~~~~~~~~~~~
+
+`precious`
+^^^^^^^^^^
+
+This attribute is set on files to indicate that their content is
+valuable. Some commands will behave slightly different on precious
+files. linkgit:git-clean[1] may leave precious files alone.
+
+
 USING MACRO ATTRIBUTES
 ----------------------
 

attr.c

@@ -1157,3 +1157,15 @@ void attr_start(void)
 	pthread_mutex_init(&g_attr_hashmap.mutex, NULL);
 	pthread_mutex_init(&check_vector.mutex, NULL);
 }
+
+int is_precious_file(struct index_state *istate, const char *path)
+{
+	static struct attr_check *check;
+	if (!check)
+		check = attr_check_initl("precious", NULL);
+	if (!check)
+		return 0;
+
+	git_check_attr(istate, path, check);
+	return ATTR_TRUE(check->items[0].value);
+}

attr.h

@@ -82,4 +82,6 @@ void git_attr_set_direction(enum git_attr_direction new_direction);
 
 void attr_start(void);
 
+int is_precious_file(struct index_state *istate, const char *path);
+
 #endif /* ATTR_H */

builtin/clean.c

@@ -18,19 +18,23 @@
 #include "color.h"
 #include "pathspec.h"
 #include "help.h"
+#include "attr.h"
 
 static int force = -1; /* unset */
 static int interactive;
+static int keep_precious;
 static struct string_list del_list = STRING_LIST_INIT_DUP;
 static unsigned int colopts;
 
 static const char *const builtin_clean_usage[] = {
-	N_("git clean [-d] [-f] [-i] [-n] [-q] [-e <pattern>] [-x | -X] [--] <paths>..."),
+	N_("git clean [<options>] [-d] [-f] [-i] [-n] [-x | -X] [--] <paths>..."),
 	NULL
 };
 
 static const char *msg_remove = N_("Removing %s\n");
 static const char *msg_would_remove = N_("Would remove %s\n");
+static const char *msg_skip_precious = N_("Skipping precious file %s\n");
+static const char *msg_would_skip_precious = N_("Would skip precious file %s\n");
 static const char *msg_skip_git_dir = N_("Skipping repository %s\n");
 static const char *msg_would_skip_git_dir = N_("Would skip repository %s\n");
 static const char *msg_warn_remove_failed = N_("failed to remove %s");
@@ -146,6 +150,11 @@ static int exclude_cb(const struct option *opt, const char *arg, int unset)
 	return 0;
 }
 
+static int skip_precious_file(struct index_state *istate, const char *path)
+{
+	return keep_precious && is_precious_file(istate, path);
+}
+
 static int remove_dirs(struct strbuf *path, const char *prefix, int force_flag,
 		int dry_run, int quiet, int *dir_gone)
 {
@@ -154,6 +163,7 @@ static int remove_dirs(struct strbuf *path, const char *prefix, int force_flag,
 	struct dirent *e;
 	int res = 0, ret = 0, gone = 1, original_len = path->len, len;
 	struct string_list dels = STRING_LIST_INIT_DUP;
+	const char *rel_path;
 
 	*dir_gone = 1;
 
@@ -193,9 +203,16 @@ static int remove_dirs(struct strbuf *path, const char *prefix, int force_flag,
 
 		strbuf_setlen(path, len);
 		strbuf_addstr(path, e->d_name);
-		if (lstat(path->buf, &st))
+		if (lstat(path->buf, &st)) {
 			; /* fall thru */
-		else if (S_ISDIR(st.st_mode)) {
+		} else if ((!prefix && skip_precious_file(&the_index, path->buf)) ||
+			   (prefix && skip_prefix(path->buf, prefix, &rel_path) &&
+			    skip_precious_file(&the_index, rel_path))) {
+			quote_path_relative(path->buf, prefix, &quoted);
+			printf(dry_run ? _(msg_would_skip_precious) : _(msg_skip_precious), quoted.buf);
+			*dir_gone = 0;
+			continue;
+		} else if (S_ISDIR(st.st_mode)) {
 			if (remove_dirs(path, prefix, force_flag, dry_run, quiet, &gone))
 				ret = 1;
 			if (gone) {
@@ -915,6 +932,8 @@ int cmd_clean(int argc, const char **argv, const char *prefix)
 		OPT_BOOL('x', NULL, &ignored, N_("remove ignored files, too")),
 		OPT_BOOL('X', NULL, &ignored_only,
 				N_("remove only ignored files")),
+		OPT_BOOL(0, "keep-precious", &keep_precious,
+			 N_("do not remove files with 'precious' attribute")),
 		OPT_END()
 	};
 
@@ -1019,7 +1038,10 @@ int cmd_clean(int argc, const char **argv, const char *prefix)
 		if (lstat(abs_path.buf, &st))
 			continue;
 
-		if (S_ISDIR(st.st_mode)) {
+		if (skip_precious_file(&the_index, item->string)) {
+			qname = quote_path_relative(item->string, NULL, &buf);
+			printf(dry_run ? _(msg_would_skip_precious) : _(msg_skip_precious), qname);
+		} else if (S_ISDIR(st.st_mode)) {
 			if (remove_dirs(&abs_path, prefix, rm_flags, dry_run, quiet, &gone))
 				errors++;
 			if (gone && !quiet) {

t/t7300-clean.sh

@@ -669,4 +669,44 @@ test_expect_success 'git clean -d skips untracked dirs containing ignored files'
 	test_path_is_missing foo/b/bb
 '
 
+test_expect_success 'git clean -xd --keep-precious leaves precious files alone' '
+	git init precious &&
+	(
+		cd precious &&
+		test_commit one &&
+		cat >.gitignore <<-\EOF &&
+		*.o
+		*.mak
+		EOF
+		cat >.gitattributes <<-\EOF &&
+		*.mak precious
+		.gitattributes precious
+		*.precious precious
+		EOF
+		mkdir sub &&
+		touch one.o sub/two.o one.mak sub/two.mak &&
+		touch one.untracked two.precious sub/also.precious &&
+		git clean -fdx --keep-precious &&
+		test_path_is_missing one.o &&
+		test_path_is_missing sub/two.o &&
+		test_path_is_missing one.untracked &&
+		test_path_is_file .gitattributes &&
+		test_path_is_file one.mak &&
+		test_path_is_file sub/two.mak &&
+		test_path_is_file two.precious &&
+		test_path_is_file sub/also.precious
+	)
+'
+
+test_expect_success 'git clean -xd still deletes them all' '
+	test_path_is_file precious/one.mak &&
+	test_path_is_file precious/sub/two.mak &&
+	test_path_is_file precious/two.precious &&
+	test_path_is_file precious/sub/also.precious &&
+	git -C precious clean -fdx &&
+	test_path_is_missing precious/one.mak &&
+	test_path_is_missing precious/sub/two.mak &&
+	test_path_is_missing precious/two.precious &&
+	test_path_is_missing precious/sub/also.precious
+'
 test_done