Re: [PATCH 4/4] replace: add a --raw mode for --edit

> One of the purposes of "git replace --edit" is to help a
> user repair objects which are malformed or corrupted.
> Usually we pretty-print trees with "ls-tree", which is much
> easier to work with than the raw binary data.  However, some
> forms of corruption break the tree-walker, in which case our
> pretty-printing fails, rendering "--edit" useless for the
> user.
>
> This patch introduces a "--raw" option, which lets you edit
> the binary data in these instances.
>
> Signed-off-by: Jeff King <peff@peff.net>
> ---

>  Documentation/git-replace.txt |  8 ++++++++
>  builtin/replace.c             | 31 +++++++++++++++++++++----------
>  2 files changed, 29 insertions(+), 10 deletions(-)
>
> diff --git a/Documentation/git-replace.txt b/Documentation/git-replace.txt
> index 61461b9..089dcac 100644
> --- a/Documentation/git-replace.txt
> +++ b/Documentation/git-replace.txt
> @@ -73,6 +73,14 @@ OPTIONS
>  	newly created object. See linkgit:git-var[1] for details about
>  	how the editor will be chosen.
>  
> +--raw::
> +	When editing, provide the raw object contents rather than
> +	pretty-printed ones. Currently this only affects trees, which
> +	will be shown in their binary form. This is harder to work with,
> +	but can help when repairing a tree that is so corrupted it
> +	cannot be pretty-printed. Note that you may need to configure
> +	your editor to cleanly read and write binary data.
> +
>  -l <pattern>::
>  --list <pattern>::
>  	List replace refs for objects that match the given pattern (or
> diff --git a/builtin/replace.c b/builtin/replace.c
> index 2584170..d1ea2c2 100644
> --- a/builtin/replace.c
> +++ b/builtin/replace.c
> @@ -188,10 +188,12 @@ static int replace_object(const char *object_ref, const char *replace_ref, int f
>  }
>  
>  /*
> - * Write the contents of the object named by "sha1" to the file "filename",
> - * pretty-printed for human editing based on its type.
> + * Write the contents of the object named by "sha1" to the file "filename".
> + * If "raw" is true, then the object's raw contents are printed according to
> + * "type". Otherwise, we pretty-print the contents for human editing.
>   */
> -static void export_object(const unsigned char *sha1, const char *filename)
> +static void export_object(const unsigned char *sha1, enum object_type type,
> +			  int raw, const char *filename)
>  {
>  	struct child_process cmd = { NULL };
>  	int fd;
> @@ -202,7 +204,10 @@ static void export_object(const unsigned char *sha1, const char *filename)
>  
>  	argv_array_push(&cmd.args, "--no-replace-objects");
>  	argv_array_push(&cmd.args, "cat-file");
> -	argv_array_push(&cmd.args, "-p");
> +	if (raw)
> +		argv_array_push(&cmd.args, typename(type));
> +	else
> +		argv_array_push(&cmd.args, "-p");
>  	argv_array_push(&cmd.args, sha1_to_hex(sha1));
>  	cmd.git_cmd = 1;
>  	cmd.out = fd;
> @@ -217,7 +222,7 @@ static void export_object(const unsigned char *sha1, const char *filename)
>   * The sha1 of the written object is returned via sha1.
>   */
>  static void import_object(unsigned char *sha1, enum object_type type,
> -			  const char *filename)
> +			  int raw, const char *filename)
>  {
>  	int fd;
>  
> @@ -225,7 +230,7 @@ static void import_object(unsigned char *sha1, enum object_type type,
>  	if (fd < 0)
>  		die_errno("unable to open %s for reading", filename);
>  
> -	if (type == OBJ_TREE) {
> +	if (!raw && type == OBJ_TREE) {
>  		const char *argv[] = { "mktree", NULL };
>  		struct child_process cmd = { argv };
>  		struct strbuf result = STRBUF_INIT;
> @@ -265,7 +270,7 @@ static void import_object(unsigned char *sha1, enum object_type type,
>  	 */
>  }
>  
> -static int edit_and_replace(const char *object_ref, int force)
> +static int edit_and_replace(const char *object_ref, int force, int raw)
>  {
>  	char *tmpfile = git_pathdup("REPLACE_EDITOBJ");
>  	enum object_type type;
> @@ -281,10 +286,10 @@ static int edit_and_replace(const char *object_ref, int force)
>  
>  	check_ref_valid(old, prev, ref, sizeof(ref), force);
>  
> -	export_object(old, tmpfile);
> +	export_object(old, type, raw, tmpfile);
>  	if (launch_editor(tmpfile, NULL, NULL) < 0)
>  		die("editing object file failed");
> -	import_object(new, type, tmpfile);
> +	import_object(new, type, raw, tmpfile);
>  
>  	free(tmpfile);
>  
> @@ -297,6 +302,7 @@ static int edit_and_replace(const char *object_ref, int force)
>  int cmd_replace(int argc, const char **argv, const char *prefix)
>  {
>  	int force = 0;
> +	int raw = 0;
>  	const char *format = NULL;
>  	enum {
>  		MODE_UNSPECIFIED = 0,
> @@ -310,6 +316,7 @@ int cmd_replace(int argc, const char **argv, const char *prefix)
>  		OPT_CMDMODE('d', "delete", &cmdmode, N_("delete replace refs"), MODE_DELETE),
>  		OPT_CMDMODE('e', "edit", &cmdmode, N_("edit existing object"), MODE_EDIT),
>  		OPT_BOOL('f', "force", &force, N_("replace the ref if it exists")),
> +		OPT_BOOL(0, "raw", &raw, N_("do not pretty-print contents for --edit")),
>  		OPT_STRING(0, "format", &format, N_("format"), N_("use this format")),
>  		OPT_END()
>  	};
> @@ -329,6 +336,10 @@ int cmd_replace(int argc, const char **argv, const char *prefix)
>  		usage_msg_opt("-f only makes sense when writing a replacement",
>  			      git_replace_usage, options);
>  
> +	if (raw && cmdmode != MODE_EDIT)
> +		usage_msg_opt("--raw only makes sense with --edit",
> +			      git_replace_usage, options);
> +
>  	switch (cmdmode) {
>  	case MODE_DELETE:
>  		if (argc < 1)
> @@ -346,7 +357,7 @@ int cmd_replace(int argc, const char **argv, const char *prefix)
>  		if (argc != 1)
>  			usage_msg_opt("-e needs exactly one argument",
>  				      git_replace_usage, options);
> -		return edit_and_replace(argv[0], force);
> +		return edit_and_replace(argv[0], force, raw);
>  
>  	case MODE_LIST:
>  		if (argc > 1)