Use gitattributes to define per-path whitespace rule

The `core.whitespace` configuration variable allows you to define what
`diff` and `apply` should consider whitespace errors for all paths in
the project (See gitlink:git-config[1]).  This attribute gives you finer
control per path.

For example, if you have these in the .gitattributes:

    frotz   whitespace
    nitfol  -whitespace
    xyzzy   whitespace=-trailing

all types of whitespace problems known to git are noticed in path 'frotz'
(i.e. diff shows them in diff.whitespace color, and apply warns about
them), no whitespace problem is noticed in path 'nitfol', and the
default types of whitespace problems except "trailing whitespace" are
noticed for path 'xyzzy'.  A project with mixed Python and C might want
to have:

    *.c    whitespace
    *.py   whitespace=-indent-with-non-tab

in its toplevel .gitattributes file.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 22 insertions, 14 deletions

diff --git a/builtin-apply.c b/builtin-apply.c
index 57efcd5aa7..ee3ef60268 100644
--- a/builtin-apply.c
+++ b/builtin-apply.c
@@ -144,6 +144,7 @@ struct patch {
 	unsigned int old_mode, new_mode;
 	int is_new, is_delete;	/* -1 = unknown, 0 = false, 1 = true */
 	int rejected;
+	unsigned ws_rule;
 	unsigned long deflate_origlen;
 	int lines_added, lines_deleted;
 	int score;
@@ -898,7 +899,7 @@ static int find_header(char *line, unsigned long size, int *hdrsize, struct patc
 	return -1;
 }
 
-static void check_whitespace(const char *line, int len)
+static void check_whitespace(const char *line, int len, unsigned ws_rule)
 {
 	const char *err = "Adds trailing whitespace";
 	int seen_space = 0;
@@ -910,14 +911,14 @@ static void check_whitespace(const char *line, int len)
 	 * this function.  That is, an addition of an empty line would
 	 * check the '+' here.  Sneaky...
 	 */
-	if ((whitespace_rule & WS_TRAILING_SPACE) && isspace(line[len-2]))
+	if ((ws_rule & WS_TRAILING_SPACE) && isspace(line[len-2]))
 		goto error;
 
 	/*
 	 * Make sure that there is no space followed by a tab in
 	 * indentation.
 	 */
-	if (whitespace_rule & WS_SPACE_BEFORE_TAB) {
+	if (ws_rule & WS_SPACE_BEFORE_TAB) {
 		err = "Space in indent is followed by a tab";
 		for (i = 1; i < len; i++) {
 			if (line[i] == '\t') {
@@ -935,7 +936,7 @@ static void check_whitespace(const char *line, int len)
 	 * Make sure that the indentation does not contain more than
 	 * 8 spaces.
 	 */
-	if ((whitespace_rule & WS_INDENT_WITH_NON_TAB) &&
+	if ((ws_rule & WS_INDENT_WITH_NON_TAB) &&
 	    (8 < len) && !strncmp("+        ", line, 9)) {
 		err = "Indent more than 8 places with spaces";
 		goto error;
@@ -1001,7 +1002,7 @@ static int parse_fragment(char *line, unsigned long size,
 		case '-':
 			if (apply_in_reverse &&
 			    ws_error_action != nowarn_ws_error)
-				check_whitespace(line, len);
+				check_whitespace(line, len, patch->ws_rule);
 			deleted++;
 			oldlines--;
 			trailing = 0;
@@ -1009,7 +1010,7 @@ static int parse_fragment(char *line, unsigned long size,
 		case '+':
 			if (!apply_in_reverse &&
 			    ws_error_action != nowarn_ws_error)
-				check_whitespace(line, len);
+				check_whitespace(line, len, patch->ws_rule);
 			added++;
 			newlines--;
 			trailing = 0;
@@ -1318,6 +1319,10 @@ static int parse_chunk(char *buffer, unsigned long size, struct patch *patch)
 	if (offset < 0)
 		return offset;
 
+	patch->ws_rule = whitespace_rule(patch->new_name
+					 ? patch->new_name
+					 : patch->old_name);
+
 	patchsize = parse_single_patch(buffer + offset + hdrsize,
 				       size - offset - hdrsize, patch);
 
@@ -1568,7 +1573,8 @@ static void remove_last_line(const char **rbuf, int *rsize)
 	*rsize = offset + 1;
 }
 
-static int apply_line(char *output, const char *patch, int plen)
+static int apply_line(char *output, const char *patch, int plen,
+		      unsigned ws_rule)
 {
 	/*
 	 * plen is number of bytes to be copied from patch,
@@ -1593,7 +1599,7 @@ static int apply_line(char *output, const char *patch, int plen)
 	/*
 	 * Strip trailing whitespace
 	 */
-	if ((whitespace_rule & WS_TRAILING_SPACE) &&
+	if ((ws_rule & WS_TRAILING_SPACE) &&
 	    (1 < plen && isspace(patch[plen-1]))) {
 		if (patch[plen] == '\n')
 			add_nl_to_tail = 1;
@@ -1610,12 +1616,12 @@ static int apply_line(char *output, const char *patch, int plen)
 		char ch = patch[i];
 		if (ch == '\t') {
 			last_tab_in_indent = i;
-			if ((whitespace_rule & WS_SPACE_BEFORE_TAB) &&
+			if ((ws_rule & WS_SPACE_BEFORE_TAB) &&
 			    0 <= last_space_in_indent)
 			    need_fix_leading_space = 1;
 		} else if (ch == ' ') {
 			last_space_in_indent = i;
-			if ((whitespace_rule & WS_INDENT_WITH_NON_TAB) &&
+			if ((ws_rule & WS_INDENT_WITH_NON_TAB) &&
 			    last_tab_in_indent < 0 &&
 			    8 <= i)
 				need_fix_leading_space = 1;
@@ -1629,7 +1635,7 @@ static int apply_line(char *output, const char *patch, int plen)
 		int consecutive_spaces = 0;
 		int last = last_tab_in_indent + 1;
 
-		if (whitespace_rule & WS_INDENT_WITH_NON_TAB) {
+		if (ws_rule & WS_INDENT_WITH_NON_TAB) {
 			/* have "last" point at one past the indent */
 			if (last_tab_in_indent < last_space_in_indent)
 				last = last_space_in_indent + 1;
@@ -1671,7 +1677,7 @@ static int apply_line(char *output, const char *patch, int plen)
 }
 
 static int apply_one_fragment(struct strbuf *buf, struct fragment *frag,
-			      int inaccurate_eof)
+			      int inaccurate_eof, unsigned ws_rule)
 {
 	int match_beginning, match_end;
 	const char *patch = frag->patch;
@@ -1730,7 +1736,7 @@ static int apply_one_fragment(struct strbuf *buf, struct fragment *frag,
 		case '+':
 			if (first != '+' || !no_add) {
 				int added = apply_line(new + newsize, patch,
-						       plen);
+						       plen, ws_rule);
 				newsize += added;
 				if (first == '+' &&
 				    added == 1 && new[newsize-1] == '\n')
@@ -1953,12 +1959,14 @@ static int apply_fragments(struct strbuf *buf, struct patch *patch)
 {
 	struct fragment *frag = patch->fragments;
 	const char *name = patch->old_name ? patch->old_name : patch->new_name;
+	unsigned ws_rule = patch->ws_rule;
+	unsigned inaccurate_eof = patch->inaccurate_eof;
 
 	if (patch->is_binary)
 		return apply_binary(buf, patch);
 
 	while (frag) {
-		if (apply_one_fragment(buf, frag, patch->inaccurate_eof)) {
+		if (apply_one_fragment(buf, frag, inaccurate_eof, ws_rule)) {
 			error("patch failed: %s:%ld", name, frag->oldpos);
 			if (!apply_with_reject)
 				return -1;