From: Junio C Hamano <gitster@pobox.com>
Date: Wed, 4 Apr 2012 16:37:02 +0000 (-0700)
Subject: update-index: upgrade/downgrade on-disk index version
X-Git-Tag: v1.7.11-rc0~76^2~2
X-Git-Url: http://git.tremily.us/?a=commitdiff_plain;h=69dec66b2f6ab5c8138cca37e74bd405c541318a;p=git.git

update-index: upgrade/downgrade on-disk index version

With the "--index-version <n>" parameter, write the index out in the
specified version.  With this, an index file that is written in newer
format (say v4) can be downgraded to be read by older versions of Git.

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

diff --git a/Documentation/git-update-index.txt b/Documentation/git-update-index.txt
index a3081f4e2..9d0b1515c 100644
--- a/Documentation/git-update-index.txt
+++ b/Documentation/git-update-index.txt
@@ -19,7 +19,7 @@ SYNOPSIS
 	     [--ignore-submodules]
 	     [--really-refresh] [--unresolve] [--again | -g]
 	     [--info-only] [--index-info]
-	     [-z] [--stdin]
+	     [-z] [--stdin] [--index-version <n>]
 	     [--verbose]
 	     [--] [<file>...]
 
@@ -143,6 +143,10 @@ you will need to handle the situation manually.
 --verbose::
         Report what is being added and removed from index.
 
+--index-version <n>::
+	Write the resulting index out in the named on-disk format version.
+	The current default version is 2.
+
 -z::
 	Only meaningful with `--stdin` or `--index-info`; paths are
 	separated with NUL character instead of LF.
diff --git a/builtin/update-index.c b/builtin/update-index.c
index a6a23fa1f..5f038d64d 100644
--- a/builtin/update-index.c
+++ b/builtin/update-index.c
@@ -708,6 +708,7 @@ int cmd_update_index(int argc, const char **argv, const char *prefix)
 	int newfd, entries, has_errors = 0, line_termination = '\n';
 	int read_from_stdin = 0;
 	int prefix_length = prefix ? strlen(prefix) : 0;
+	int preferred_index_format = 0;
 	char set_executable_bit = 0;
 	struct refresh_params refresh_args = {0, &has_errors};
 	int lock_error = 0;
@@ -791,6 +792,8 @@ int cmd_update_index(int argc, const char **argv, const char *prefix)
 			"(for porcelains) forget saved unresolved conflicts",
 			PARSE_OPT_NOARG | PARSE_OPT_NONEG,
 			resolve_undo_clear_callback},
+		OPT_INTEGER(0, "index-version", &preferred_index_format,
+			    "write index in this format"),
 		OPT_END()
 	};
 
@@ -851,6 +854,17 @@ int cmd_update_index(int argc, const char **argv, const char *prefix)
 		}
 	}
 	argc = parse_options_end(&ctx);
+	if (preferred_index_format) {
+		if (preferred_index_format < INDEX_FORMAT_LB ||
+		    INDEX_FORMAT_UB < preferred_index_format)
+			die("index-version %d not in range: %d..%d",
+			    preferred_index_format,
+			    INDEX_FORMAT_LB, INDEX_FORMAT_UB);
+
+		if (the_index.version != preferred_index_format)
+			active_cache_changed = 1;
+		the_index.version = preferred_index_format;
+	}
 
 	if (read_from_stdin) {
 		struct strbuf buf = STRBUF_INIT, nbuf = STRBUF_INIT;