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>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/git-replace.txt b/Documentation/git-replace.txt
index 61461b9..089dcac 100644 (file)
--- 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 (file)
--- 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)