From 1ce4790bf5eeceb212f003fffcb36069c0ebb45e Mon Sep 17 00:00:00 2001
From: Alex Riesen <raa.lkml@gmail.com>
Date: Mon, 28 Jul 2008 08:31:28 +0200
Subject: Make use of stat.ctime configurable

A new configuration variable 'core.trustctime' is introduced to
allow ignoring st_ctime information when checking if paths
in the working tree has changed, because there are situations where
it produces too much false positives.  Like when file system crawlers
keep changing it when scanning and using the ctime for marking scanned
files.

The default is to notice ctime changes.

Signed-off-by: Alex Riesen <raa.lkml@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/config.txt b/Documentation/config.txt
index 1a13abc..61c3760 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -117,6 +117,13 @@ core.fileMode::
 	the working copy are ignored; useful on broken filesystems like FAT.
 	See linkgit:git-update-index[1]. True by default.
 
+core.trustctime::
+	If false, the ctime differences between the index and the
+	working copy are ignored; useful when the inode change time
+	is regularly modified by something outside Git (file system
+	crawlers and some backup systems).
+	See linkgit:git-update-index[1]. True by default.
+
 core.quotepath::
 	The commands that output paths (e.g. 'ls-files',
 	'diff'), when not given the `-z` option, will quote
diff --git a/Documentation/git-update-index.txt b/Documentation/git-update-index.txt
index 6b930bc..1d9d81a 100644
--- a/Documentation/git-update-index.txt
+++ b/Documentation/git-update-index.txt
@@ -323,6 +323,11 @@ from symbolic link to regular file.
 The command looks at `core.ignorestat` configuration variable.  See
 'Using "assume unchanged" bit' section above.
 
+The command also looks at `core.trustctime` configuration variable.
+It can be useful when the inode change time is regularly modified by
+something outside Git (file system crawlers and backup systems use
+ctime for marking files processed) (see linkgit:git-config[1]).
+
 
 SEE ALSO
 --------
diff --git a/cache.h b/cache.h
index 4b6c0a6..2475de9 100644
--- a/cache.h
+++ b/cache.h
@@ -423,6 +423,7 @@ extern int delete_ref(const char *, const unsigned char *sha1);
 
 /* Environment bits from configuration mechanism */
 extern int trust_executable_bit;
+extern int trust_ctime;
 extern int quote_path_fully;
 extern int has_symlinks;
 extern int ignore_case;
diff --git a/config.c b/config.c
index 1e066c7..53f04a0 100644
--- a/config.c
+++ b/config.c
@@ -341,6 +341,10 @@ static int git_default_core_config(const char *var, const char *value)
 		trust_executable_bit = git_config_bool(var, value);
 		return 0;
 	}
+	if (!strcmp(var, "core.trustctime")) {
+		trust_ctime = git_config_bool(var, value);
+		return 0;
+	}
 
 	if (!strcmp(var, "core.quotepath")) {
 		quote_path_fully = git_config_bool(var, value);
diff --git a/environment.c b/environment.c
index 4a88a17..0c6d11f 100644
--- a/environment.c
+++ b/environment.c
@@ -13,6 +13,7 @@ char git_default_email[MAX_GITNAME];
 char git_default_name[MAX_GITNAME];
 int user_ident_explicitly_given;
 int trust_executable_bit = 1;
+int trust_ctime = 1;
 int has_symlinks = 1;
 int ignore_case;
 int assume_unchanged;
diff --git a/read-cache.c b/read-cache.c
index 6c08803..1cae361 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -197,7 +197,7 @@ static int ce_match_stat_basic(struct cache_entry *ce, struct stat *st)
 	}
 	if (ce->ce_mtime != (unsigned int) st->st_mtime)
 		changed |= MTIME_CHANGED;
-	if (ce->ce_ctime != (unsigned int) st->st_ctime)
+	if (trust_ctime && ce->ce_ctime != (unsigned int) st->st_ctime)
 		changed |= CTIME_CHANGED;
 
 	if (ce->ce_uid != (unsigned int) st->st_uid ||
-- 
cgit v0.10.2-6-g49f6