wt-status: make the require_clean_work_tree() function reusable

The function used by "git pull" to stop the user when the working
tree has changes is useful in other places.

Let's move it into a more prominent (and into an actually reusable)
spot: wt-status.[ch].

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/pull.c

@@ -17,6 +17,7 @@
 #include "revision.h"
 #include "tempfile.h"
 #include "lockfile.h"
+#include "wt-status.h"
 
 enum rebase_type {
 	REBASE_INVALID = -1,
@@ -325,82 +326,6 @@ static int git_pull_config(const char *var, const char *value, void *cb)
 	return git_default_config(var, value, cb);
 }
 
-/**
- * Returns 1 if there are unstaged changes, 0 otherwise.
- */
-static int has_unstaged_changes(void)
-{
-	struct rev_info rev_info;
-	int result;
-
-	init_revisions(&rev_info, NULL);
-	DIFF_OPT_SET(&rev_info.diffopt, IGNORE_SUBMODULES);
-	DIFF_OPT_SET(&rev_info.diffopt, QUICK);
-	diff_setup_done(&rev_info.diffopt);
-	result = run_diff_files(&rev_info, 0);
-	return diff_result_code(&rev_info.diffopt, result);
-}
-
-/**
- * Returns 1 if there are uncommitted changes, 0 otherwise.
- */
-static int has_uncommitted_changes(void)
-{
-	struct rev_info rev_info;
-	int result;
-
-	if (is_cache_unborn())
-		return 0;
-
-	init_revisions(&rev_info, NULL);
-	DIFF_OPT_SET(&rev_info.diffopt, IGNORE_SUBMODULES);
-	DIFF_OPT_SET(&rev_info.diffopt, QUICK);
-	add_head_to_pending(&rev_info);
-	diff_setup_done(&rev_info.diffopt);
-	result = run_diff_index(&rev_info, 1);
-	return diff_result_code(&rev_info.diffopt, result);
-}
-
-/**
- * If the work tree has unstaged or uncommitted changes, dies with the
- * appropriate message.
- */
-static int require_clean_work_tree(const char *action, const char *hint,
-		int gently)
-{
-	struct lock_file *lock_file = xcalloc(1, sizeof(*lock_file));
-	int err = 0;
-
-	hold_locked_index(lock_file, 0);
-	refresh_cache(REFRESH_QUIET);
-	update_index_if_able(&the_index, lock_file);
-	rollback_lock_file(lock_file);
-
-	if (has_unstaged_changes()) {
-		/* TRANSLATORS: the action is e.g. "pull with rebase" */
-		error(_("Cannot %s: You have unstaged changes."), _(action));
-		err = 1;
-	}
-
-	if (has_uncommitted_changes()) {
-		if (err)
-			error(_("Additionally, your index contains uncommitted changes."));
-		else
-			error(_("Cannot %s: Your index contains uncommitted changes."),
-			      _(action));
-		err = 1;
-	}
-
-	if (err) {
-		if (hint)
-			error("%s", hint);
-		if (!gently)
-			exit(128);
-	}
-
-	return err;
-}
-
 /**
  * Appends merge candidates from FETCH_HEAD that are not marked not-for-merge
  * into merge_heads.

wt-status.c

@@ -16,6 +16,7 @@
 #include "strbuf.h"
 #include "utf8.h"
 #include "worktree.h"
+#include "lockfile.h"
 
 static const char cut_line[] =
 "------------------------ >8 ------------------------\n";
@@ -2209,3 +2210,78 @@ void wt_status_print(struct wt_status *s)
 		break;
 	}
 }
+
+/**
+ * Returns 1 if there are unstaged changes, 0 otherwise.
+ */
+static int has_unstaged_changes(void)
+{
+	struct rev_info rev_info;
+	int result;
+
+	init_revisions(&rev_info, NULL);
+	DIFF_OPT_SET(&rev_info.diffopt, IGNORE_SUBMODULES);
+	DIFF_OPT_SET(&rev_info.diffopt, QUICK);
+	diff_setup_done(&rev_info.diffopt);
+	result = run_diff_files(&rev_info, 0);
+	return diff_result_code(&rev_info.diffopt, result);
+}
+
+/**
+ * Returns 1 if there are uncommitted changes, 0 otherwise.
+ */
+static int has_uncommitted_changes(void)
+{
+	struct rev_info rev_info;
+	int result;
+
+	if (is_cache_unborn())
+		return 0;
+
+	init_revisions(&rev_info, NULL);
+	DIFF_OPT_SET(&rev_info.diffopt, IGNORE_SUBMODULES);
+	DIFF_OPT_SET(&rev_info.diffopt, QUICK);
+	add_head_to_pending(&rev_info);
+	diff_setup_done(&rev_info.diffopt);
+	result = run_diff_index(&rev_info, 1);
+	return diff_result_code(&rev_info.diffopt, result);
+}
+
+/**
+ * If the work tree has unstaged or uncommitted changes, dies with the
+ * appropriate message.
+ */
+int require_clean_work_tree(const char *action, const char *hint, int gently)
+{
+	struct lock_file *lock_file = xcalloc(1, sizeof(*lock_file));
+	int err = 0;
+
+	hold_locked_index(lock_file, 0);
+	refresh_cache(REFRESH_QUIET);
+	update_index_if_able(&the_index, lock_file);
+	rollback_lock_file(lock_file);
+
+	if (has_unstaged_changes()) {
+		/* TRANSLATORS: the action is e.g. "pull with rebase" */
+		error(_("Cannot %s: You have unstaged changes."), _(action));
+		err = 1;
+	}
+
+	if (has_uncommitted_changes()) {
+		if (err)
+			error(_("Additionally, your index contains uncommitted changes."));
+		else
+			error(_("Cannot %s: Your index contains uncommitted changes."),
+			      _(action));
+		err = 1;
+	}
+
+	if (err) {
+		if (hint)
+			error("%s", hint);
+		if (!gently)
+			exit(128);
+	}
+
+	return err;
+}

wt-status.h

@@ -128,4 +128,7 @@ void status_printf_ln(struct wt_status *s, const char *color, const char *fmt, .
 __attribute__((format (printf, 3, 4)))
 void status_printf(struct wt_status *s, const char *color, const char *fmt, ...);
 
+/* The following function expects that the caller took care of reading the index. */
+int require_clean_work_tree(const char *action, const char *hint, int gently);
+
 #endif /* STATUS_H */