dev-vcs/git-2.4.10 patch for git diff to work for process substitution: `$ git diff --color-words <(echo a b c) <(echo a d c)`

git-diff-process-substitution.patch

diff --git a/Documentation/git-diff.txt b/Documentation/git-diff.txt
index bbab35f..f4ca476 100644
--- a/Documentation/git-diff.txt
+++ b/Documentation/git-diff.txt
@@ -99,10 +99,17 @@ include::diff-options.txt[]
 
 <path>...::
 	The <paths> parameters, when given, are used to limit
 	the diff to the named paths (you can give directory
 	names and get diff for all files under them).
+	+
+	With --no-index, or with paths outside the worktree,
+	some paths are handled specially: - and /dev/stdin
+	refer to standard input, and /dev/fd/* can be used
+	to refer to existing file descriptors, as in:
+
+	$ git diff --color-words <(echo a b c) <(echo a d c)
 
 
 include::diff-format.txt[]
 
 EXAMPLES
diff --git a/diff-no-index.c b/diff-no-index.c
index 265709b..586036b 100644
--- a/diff-no-index.c
+++ b/diff-no-index.c
@@ -70,11 +70,11 @@ static int populate_from_stdin(struct diff_filespec *s)
 
 	s->should_munmap = 0;
 	s->data = strbuf_detach(&buf, &size);
 	s->size = size;
 	s->should_free = 1;
-	s->is_stdin = 1;
+	s->skip_hashing = 1;
 	return 0;
 }
 
 static struct diff_filespec *noindex_filespec(const char *name, int mode)
 {
@@ -84,10 +84,16 @@ static struct diff_filespec *noindex_filespec(const char *name, int mode)
 		name = "/dev/null";
 	s = alloc_filespec(name);
 	fill_filespec(s, null_sha1, 0, mode);
 	if (name == file_from_standard_input)
 		populate_from_stdin(s);
+	else if (!strcmp(name, "/dev/stdin") ||
+			 !strncmp(name, "/dev/fd/", 8) ||
+			 !strncmp(name, "/proc/self/fd/", 14)) {
+		s->skip_hashing = 1;
+		s->follow_symlinks = 1;
+	}
 	return s;
 }
 
 static int queue_diff(struct diff_options *o,
 		      const char *name1, const char *name2)
diff --git a/diff.c b/diff.c
index d7a5c81..c1150d7 100644
--- a/diff.c
+++ b/diff.c
@@ -2713,22 +2713,26 @@ int diff_populate_filespec(struct diff_filespec *s, unsigned int flags)
 	    reuse_worktree_file(s->path, s->sha1, 0)) {
 		struct strbuf buf = STRBUF_INIT;
 		struct stat st;
 		int fd;
 
-		if (lstat(s->path, &st) < 0) {
+		if (s->follow_symlinks)
+			err = stat(s->path, &st);
+		else
+			err = lstat(s->path, &st);
+		if (err < 0) {
 			if (errno == ENOENT) {
 			err_empty:
 				err = -1;
 			empty:
 				s->data = (char *)"";
 				s->size = 0;
 				return err;
 			}
 		}
 		s->size = xsize_t(st.st_size);
-		if (!s->size)
+		if (S_ISREG(st.st_mode) && !s->size)
 			goto empty;
 		if (S_ISLNK(st.st_mode)) {
 			struct strbuf sb = STRBUF_INIT;
 
 			if (strbuf_readlink(&sb, s->path, s->size))
@@ -2746,13 +2750,25 @@ int diff_populate_filespec(struct diff_filespec *s, unsigned int flags)
 			return 0;
 		}
 		fd = open(s->path, O_RDONLY);
 		if (fd < 0)
 			goto err_empty;
-		s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
+		if (S_ISREG(st.st_mode)) {
+			s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
+			s->should_munmap = 1;
+		} else {
+			struct strbuf sb = STRBUF_INIT;
+			if (strbuf_read(&sb, fd, s->size) < 0) {
+				err = error("error while reading from %s: %s",
+				     s->path, strerror(errno));
+				goto err_empty;
+			}
+			s->data = strbuf_detach(&sb, &s->size);
+			s->should_munmap = 0;
+			s->should_free = 1;
+		}
 		close(fd);
-		s->should_munmap = 1;
 
 		/*
 		 * Convert from working tree format to canonical git format
 		 */
 		if (convert_to_git(s->path, s->data, s->size, &buf, crlf_warn)) {
@@ -3084,11 +3100,11 @@ static void run_diff_cmd(const char *pgm,
 static void diff_fill_sha1_info(struct diff_filespec *one)
 {
 	if (DIFF_FILE_VALID(one)) {
 		if (!one->sha1_valid) {
 			struct stat st;
-			if (one->is_stdin) {
+			if (one->skip_hashing) {
 				hashcpy(one->sha1, null_sha1);
 				return;
 			}
 			if (lstat(one->path, &st) < 0)
 				die_errno("stat '%s'", one->path);
diff --git a/diffcore.h b/diffcore.h
index 33ea2de..e19b379 100644
--- a/diffcore.h
+++ b/diffcore.h
@@ -32,20 +32,22 @@ struct diff_filespec {
 	unsigned long size;
 	int count;               /* Reference count */
 	int rename_used;         /* Count of rename users */
 	unsigned short mode;	 /* file mode */
 	unsigned sha1_valid : 1; /* if true, use sha1 and trust mode;
-				  * if false, use the name and read from
-				  * the filesystem.
+				  * if false, and skip_hashing is false, fill sha1
+				  * by using path and reading from the filesystem.
+				  * If skip_hashing is true, use null_sha1.
 				  */
 #define DIFF_FILE_VALID(spec) (((spec)->mode) != 0)
 	unsigned should_free : 1; /* data should be free()'ed */
 	unsigned should_munmap : 1; /* data should be munmap()'ed */
 	unsigned dirty_submodule : 2;  /* For submodules: its work tree is dirty */
 #define DIRTY_SUBMODULE_UNTRACKED 1
 #define DIRTY_SUBMODULE_MODIFIED  2
-	unsigned is_stdin : 1;
+	unsigned skip_hashing : 1;
+	unsigned follow_symlinks : 1;
 	unsigned has_more_entries : 1; /* only appear in combined diff */
 	/* data should be considered "binary"; -1 means "don't know yet" */
 	signed int is_binary : 2;
 	struct userdiff_driver *driver;
 };