[PATCH] Teach '--with-tree' option to check-attr

[PATCH] Teach '--with-tree' option to check-attr

[Jay Soffian]

Jakub Narebski writes:

> Nb. the ability to read gitattributes from given commit would be
> useful also for gitweb (the `encoding` gitattribute, etc.).

Signed-off-by: Jay Soffian <jaysoffian@gmail.com>
---
2011/9/22 Jakub Narebski <jnareb@gmail.com>:

> Unfortunately it doesn't seem to be there mechanism to query about
> state of gitattributes at given commit.
>
> There is a slight problem from the UI point of view of git-check-attr,
> namely that there are _three_ pieces of information: a place to read
> .gitattributes from (working tree, index, commit), list of attributes
> to check (or --all) and list of files (list of paths). You can use
> "--" to separate _two_ pieces of information.
>
> Nb. the ability to read gitattributes from given commit would be
> useful also for gitweb (the `encoding` gitattribute, etc.).

How's this? Builds on top of js/check-attr-cached.

 Documentation/git-check-attr.txt |    4 ++++
 builtin/check-attr.c             |   33 ++++++++++++++++++++++++++++++++-
 t/t0003-attributes.sh            |    7 +++++++
 3 files changed, 43 insertions(+), 1 deletions(-)

diff --git a/Documentation/git-check-attr.txt b/Documentation/git-check-attr.txt
index 5abdbaa51c..06e5d95e0b 100644
--- a/Documentation/git-check-attr.txt
+++ b/Documentation/git-check-attr.txt
@@ -27,6 +27,10 @@ OPTIONS
 --cached::
 	Consider `.gitattributes` in the index only, ignoring the working tree.
 
+--with-tree=<tree-ish>::
+	Consider .gitattributes in <tree-ish> only, ignoring the working tree
+	and index.
+
 --stdin::
 	Read file names from stdin instead of from the command-line.
 
diff --git a/builtin/check-attr.c b/builtin/check-attr.c
index ded0d836d3..fe926d3c97 100644
--- a/builtin/check-attr.c
+++ b/builtin/check-attr.c
@@ -3,10 +3,13 @@
 #include "attr.h"
 #include "quote.h"
 #include "parse-options.h"
+#include "tree-walk.h"
+#include "unpack-trees.h"
 
 static int all_attrs;
 static int cached_attrs;
 static int stdin_paths;
+static const char *with_tree;
 static const char * const check_attr_usage[] = {
 "git check-attr [-a | --all | attr...] [--] pathname...",
 "git check-attr --stdin [-a | --all | attr...] < <list-of-paths>",
@@ -18,6 +21,7 @@ static int null_term_line;
 static const struct option check_attr_options[] = {
 	OPT_BOOLEAN('a', "all", &all_attrs, "report all attributes set on file"),
 	OPT_BOOLEAN(0,  "cached", &cached_attrs, "use .gitattributes only from the index"),
+	OPT_STRING(0,  "with-tree", &with_tree, "tree-ish", "use .gitattributes only from <tree-ish>"),
 	OPT_BOOLEAN(0 , "stdin", &stdin_paths, "read file names from stdin"),
 	OPT_BOOLEAN('z', NULL, &null_term_line,
 		"input paths are terminated by a null character"),
@@ -101,8 +105,35 @@ int cmd_check_attr(int argc, const char **argv, const char *prefix)
 		die("invalid cache");
 	}
 
-	if (cached_attrs)
+	if (cached_attrs && with_tree)
+		error_with_usage("Cannot use --cached and --with-tree together");
+
+	if (cached_attrs) {
 		git_attr_set_direction(GIT_ATTR_INDEX, NULL);
+	} else if (with_tree) {
+		unsigned char sha1[20];
+		struct tree *tree;
+		struct unpack_trees_options opts;
+		struct tree_desc t;
+
+		if (get_sha1(with_tree, sha1))
+			die("Not a valid object name");
+
+		tree = parse_tree_indirect(sha1);
+		if (tree == NULL)
+			die("Not a tree object");
+
+		memset(&opts, 0, sizeof(opts));
+		opts.index_only = 1;
+		opts.head_idx = -1;
+		opts.src_index = &the_index;
+		opts.dst_index = &the_index;
+		opts.fn = oneway_merge;
+		init_tree_desc(&t, tree->buffer, tree->size);
+		if (unpack_trees(1, &t, &opts))
+			return -1;
+		git_attr_set_direction(GIT_ATTR_INDEX, &the_index);
+	}
 
 	doubledash = -1;
 	for (i = 0; doubledash < 0 && i < argc; i++) {
diff --git a/t/t0003-attributes.sh b/t/t0003-attributes.sh
index 46b0736b35..36ac3a02da 100755
--- a/t/t0003-attributes.sh
+++ b/t/t0003-attributes.sh
@@ -140,6 +140,7 @@ test_expect_success 'root subdir attribute test' '
 '
 
 test_expect_success 'setup bare' '
+	git commit -m ".gitattributes for testing --with-tree below" &&
 	git clone --bare . bare.git &&
 	cd bare.git
 '
@@ -163,6 +164,12 @@ test_expect_success 'bare repository: check that --cached honors index' '
 	test_cmp ../specified-all actual
 '
 
+test_expect_success 'bare repository: check --with-tree' '
+	git check-attr --with-tree=HEAD --stdin --all < ../stdin-all |
+		sort > actual &&
+	test_cmp ../specified-all actual
+'
+
 test_expect_success 'bare repository: test info/attributes' '
 	(
 		echo "f	test=f"
-- 
1.7.7.rc2.5.g12a2f