diff --git a/apply.c b/apply.c
index 43a0aebf4eec85..509f080809af75 100644
--- a/apply.c
+++ b/apply.c
@@ -22,6 +22,7 @@
 #include "rerere.h"
 #include "apply.h"
 #include "entry.h"
+#include "ws.h"
 
 struct gitdiff_data {
 	struct strbuf *root;
diff --git a/cache.h b/cache.h
index eba12487b99caa..59b9c576d98fc2 100644
--- a/cache.h
+++ b/cache.h
@@ -1800,32 +1800,6 @@ extern int diff_auto_refresh_index;
 void shift_tree(struct repository *, const struct object_id *, const struct object_id *, struct object_id *, int);
 void shift_tree_by(struct repository *, const struct object_id *, const struct object_id *, struct object_id *, const char *);
 
-/*
- * whitespace rules.
- * used by both diff and apply
- * last two digits are tab width
- */
-#define WS_BLANK_AT_EOL         0100
-#define WS_SPACE_BEFORE_TAB     0200
-#define WS_INDENT_WITH_NON_TAB  0400
-#define WS_CR_AT_EOL           01000
-#define WS_BLANK_AT_EOF        02000
-#define WS_TAB_IN_INDENT       04000
-#define WS_TRAILING_SPACE      (WS_BLANK_AT_EOL|WS_BLANK_AT_EOF)
-#define WS_DEFAULT_RULE (WS_TRAILING_SPACE|WS_SPACE_BEFORE_TAB|8)
-#define WS_TAB_WIDTH_MASK        077
-/* All WS_* -- when extended, adapt diff.c emit_symbol */
-#define WS_RULE_MASK           07777
-extern unsigned whitespace_rule_cfg;
-unsigned whitespace_rule(struct index_state *, const char *);
-unsigned parse_whitespace_rule(const char *);
-unsigned ws_check(const char *line, int len, unsigned ws_rule);
-void ws_check_emit(const char *line, int len, unsigned ws_rule, FILE *stream, const char *set, const char *reset, const char *ws);
-char *whitespace_error_string(unsigned ws);
-void ws_fix_copy(struct strbuf *, const char *, int, unsigned, int *);
-int ws_blank_line(const char *line, int len, unsigned ws_rule);
-#define ws_tab_width(rule)     ((rule) & WS_TAB_WIDTH_MASK)
-
 /* ls-files */
 void overlay_tree_on_index(struct index_state *istate,
 			   const char *tree_name, const char *prefix);
diff --git a/config.c b/config.c
index c5873f3a70643a..67cd66e33ca78c 100644
--- a/config.c
+++ b/config.c
@@ -21,6 +21,7 @@
 #include "dir.h"
 #include "color.h"
 #include "refs.h"
+#include "ws.h"
 
 struct config_source {
 	struct config_source *prev;
diff --git a/diff.c b/diff.c
index 861282db1c3283..5b123758fca64d 100644
--- a/diff.c
+++ b/diff.c
@@ -27,6 +27,7 @@
 #include "help.h"
 #include "promisor-remote.h"
 #include "dir.h"
+#include "ws.h"
 
 #ifdef NO_FAST_WORKING_DIRECTORY
 #define FAST_WORKING_DIRECTORY 0
diff --git a/environment.c b/environment.c
index 9da7f3c1a19ee5..d7cbea26f82cc2 100644
--- a/environment.c
+++ b/environment.c
@@ -19,6 +19,7 @@
 #include "object-store.h"
 #include "chdir-notify.h"
 #include "shallow.h"
+#include "ws.h"
 
 int trust_executable_bit = 1;
 int trust_ctime = 1;
diff --git a/ws.c b/ws.c
index 6e69877f257916..bbb5f71e21e3d3 100644
--- a/ws.c
+++ b/ws.c
@@ -4,6 +4,7 @@
  * Copyright (c) 2007 Junio C Hamano
  */
 #include "cache.h"
+#include "ws.h"
 #include "attr.h"
 
 static struct whitespace_rule {
diff --git a/ws.h b/ws.h
new file mode 100644
index 00000000000000..fcaac979288f49
--- /dev/null
+++ b/ws.h
@@ -0,0 +1,30 @@
+#ifndef WS_H
+#define WS_H
+
+/*
+ * whitespace rules.
+ * used by both diff and apply
+ * last two digits are tab width
+ */
+#define WS_BLANK_AT_EOL         0100
+#define WS_SPACE_BEFORE_TAB     0200
+#define WS_INDENT_WITH_NON_TAB  0400
+#define WS_CR_AT_EOL           01000
+#define WS_BLANK_AT_EOF        02000
+#define WS_TAB_IN_INDENT       04000
+#define WS_TRAILING_SPACE      (WS_BLANK_AT_EOL|WS_BLANK_AT_EOF)
+#define WS_DEFAULT_RULE (WS_TRAILING_SPACE|WS_SPACE_BEFORE_TAB|8)
+#define WS_TAB_WIDTH_MASK        077
+/* All WS_* -- when extended, adapt diff.c emit_symbol */
+#define WS_RULE_MASK           07777
+extern unsigned whitespace_rule_cfg;
+unsigned whitespace_rule(struct index_state *, const char *);
+unsigned parse_whitespace_rule(const char *);
+unsigned ws_check(const char *line, int len, unsigned ws_rule);
+void ws_check_emit(const char *line, int len, unsigned ws_rule, FILE *stream, const char *set, const char *reset, const char *ws);
+char *whitespace_error_string(unsigned ws);
+void ws_fix_copy(struct strbuf *, const char *, int, unsigned, int *);
+int ws_blank_line(const char *line, int len, unsigned ws_rule);
+#define ws_tab_width(rule)     ((rule) & WS_TAB_WIDTH_MASK)
+
+#endif