Re: git show doesn't work on file names with square brackets

[Jeff King <peff@peff.net>]

On Mon, Feb 08, 2016 at 02:52:30PM -0500, Jeff King wrote:

> Here is my patch again, with that part removed, and the tests fixed up.
> Though on reflection, I do think it would be better if we could simply
> expand the wildcard globs to say "does this match anything in the file
> system". That makes a nice, simple rule that follows the spirit of the
> original. I'm not sure if it would be easy to apply magic like ":(top)"
> there, but even if we don't, we're not worse off than we are today
> (where that requires "--" unless it happens to have a wildcard, as
> above).

So here is a hacky attempt at that. It uses glob(), which is not quite
right for the reasons below, though I suspect works OK in practice.

I think doing it correctly would require actually calling our
read_directory() function. That feels kind of heavy-weight for this
case, but I guess in theory the pathspec limits it (and it's not like
glob() does not have to walk the filesystem, too). So maybe it's not so
bad.

---
diff --git a/setup.c b/setup.c
index 2c4b22c..d8a7b9d 100644
--- a/setup.c
+++ b/setup.c
@@ -1,6 +1,7 @@
 #include "cache.h"
 #include "dir.h"
 #include "string-list.h"
+#include <glob.h>
 
 static int inside_git_dir = -1;
 static int inside_work_tree = -1;
@@ -130,6 +131,26 @@ int path_inside_repo(const char *prefix, const char *path)
 	return 0;
 }
 
+/*
+ * Return true if a file exists that matches the pattern
+ * glob. Note that this _should_ use our regular wildmatch
+ * pattern matches, but there is no ready-made glob()
+ * function there. This is a cheap hack that makes
+ * simple things like "*.c" work without having to
+ * use a "--" disambiguator.
+ *
+ * A custom glob() could also do this more efficiently; we don't
+ * care about collecting the results, and can quit as soon as
+ * we see one.
+ */
+static int glob_exists(const char *pattern)
+{
+	glob_t data;
+	int r = glob(pattern, GLOB_NOSORT, NULL, &data);
+	globfree(&data);
+	return !r;
+}
+
 int check_filename(const char *prefix, const char *arg)
 {
 	const char *name;
@@ -139,12 +160,14 @@ int check_filename(const char *prefix, const char *arg)
 		if (arg[2] == '\0') /* ":/" is root dir, always exists */
 			return 1;
 		name = arg + 2;
-	} else if (!no_wildcard(arg))
-		return 1;
-	else if (prefix)
+	} else if (prefix)
 		name = prefix_filename(prefix, strlen(prefix), arg);
 	else
 		name = arg;
+
+	if (!no_wildcard(arg))
+		return glob_exists(name);
+
 	if (!lstat(name, &st))
 		return 1; /* file exists */
 	if (errno == ENOENT || errno == ENOTDIR)