git-add: add ignored files when asked explicitly.

One thing many people found confusing about git-add was that a
file whose name matches an ignored pattern could not be added to
the index.  With this, such a file can be added by explicitly
spelling its name to git-add.

Fileglobs and recursive behaviour do not add ignored files to
the index.  That is, if a pattern '*.o' is in .gitignore, and
two files foo.o, bar/baz.o are in the working tree:

    $ git add foo.o
    $ git add '*.o'
    $ git add bar

Only the first form adds foo.o to the index.

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

Documentation/git-add.txt

@@ -25,8 +25,9 @@ the commit.
 The 'git status' command can be used to obtain a summary of what is included
 for the next commit.
 
-This command only adds non-ignored files, to add ignored files use
-"git update-index --add".
+This command can be used to add ignored files, but they have to be
+explicitly and exactly specified from the command line.  File globbing
+and recursive behaviour do not add ignored files.
 
 Please see gitlink:git-commit[1] for alternative ways to add content to a
 commit.
@@ -35,7 +36,11 @@ commit.
 OPTIONS
 -------
 <file>...::
-	Files to add content from.
+	Files to add content from.  Fileglobs (e.g. `*.c`) can
+	be given to add all matching files.  Also a
+	leading directory name (e.g. `dir` to add `dir/file1`
+	and `dir/file2`) can be given to add all files in the
+	directory, recursively.
 
 -n::
         Don't actually add the file(s), just show if they exist.

builtin-add.c

@@ -26,7 +26,14 @@ static void prune_directory(struct dir_struct *dir, const char **pathspec, int p
 	i = dir->nr;
 	while (--i >= 0) {
 		struct dir_entry *entry = *src++;
-		if (!match_pathspec(pathspec, entry->name, entry->len, prefix, seen)) {
+		int how = match_pathspec(pathspec, entry->name, entry->len,
+					 prefix, seen);
+		/*
+		 * ignored entries can be added with exact match,
+		 * but not with glob nor recursive.
+		 */
+		if (!how ||
+		    (entry->ignored_entry && how != MATCHED_EXACTLY)) {
 			free(entry);
 			continue;
 		}
@@ -55,6 +62,8 @@ static void fill_directory(struct dir_struct *dir, const char **pathspec)
 
 	/* Set up the default git porcelain excludes */
 	memset(dir, 0, sizeof(*dir));
+	if (pathspec)
+		dir->show_both = 1;
 	dir->exclude_per_dir = ".gitignore";
 	path = git_path("info/exclude");
 	if (!access(path, R_OK))