git-ls-files: Fix, document, and add test for --error-unmatch option.

Signed-off-by: Junio C Hamano <junkio@cox.net>

Documentation/git-ls-files.txt

@@ -14,6 +14,7 @@ SYNOPSIS
 		[-x <pattern>|--exclude=<pattern>]
 		[-X <file>|--exclude-from=<file>]
 		[--exclude-per-directory=<file>] 
+		[--error-unmatch]
 		[--full-name] [--] [<file>]\*
 
 DESCRIPTION
@@ -72,6 +73,10 @@ OPTIONS
 	read additional exclude patterns that apply only to the
 	directory and its subdirectories in <file>.
 
+--error-unmatch::
+	If any <file> does not appear in the index, treat this as an
+	error (return 1).
+
 -t::
 	Identify the file status with the following tags (followed by
 	a space) at the start of each line:

ls-files.c

@@ -758,6 +758,7 @@ int main(int argc, const char **argv)
 				continue;
 			error("pathspec '%s' did not match any.",
 			      pathspec[num] + prefix_offset);
+			errors++;
 		}
 		return errors ? 1 : 0;
 	}

t/t3020-ls-files-error-unmatch.sh

@@ -0,0 +1,27 @@
+#!/bin/sh
+#
+# Copyright (c) 2006 Carl D. Worth
+#
+
+test_description='git-ls-files test for --error-unmatch option
+
+This test runs git-ls-files --error-unmatch to ensure it correctly
+returns an error when a non-existent path is provided on the command
+line.
+'
+. ./test-lib.sh
+
+touch foo bar
+git-update-index --add foo bar
+git-commit -m "add foo bar"
+
+test_expect_failure \
+    'git-ls-files --error-unmatch should fail with unmatched path.' \
+    'git-ls-files --error-unmatch foo bar-does-not-match'
+
+test_expect_success \
+    'git-ls-files --error-unmatch should succeed eith matched paths.' \
+    'git-ls-files --error-unmatch foo bar'
+
+test_done
+1