GIT_ONE_FILESYSTEM: flip the default to stop at filesystem boundaries

Regarding the new environment variable, Linus Torvalds
<torvalds@linux-foundation.org> writes on Tue, 30 Mar 2010 in
<alpine.LFD.2.00.1003301537150.3707@i5.linux-foundation.org>:

    I suspect that it is _very_ unusual to have a source repo that crosses
    multiple filesystems, and the original reason for this patch-series
    seems to me to be likely to be more common than that multi-fs case. So
    having the logic go the other way would seem to match the common case,
    no?

The "crossing filesystem boundary" condition is checked by comparing
st_dev field in the result from stat(2).  This is slightly worrysome if
non-POSIX ports return different values in the field even for directories
in the same work tree extracted to the same "filesystem".  Erik Faye-Lund
confirms that in the msysgit port st_dev is 0, so this should be safe, as
"even Windows is safe" ;-)

This will affect those who use /.git to cram /etc and /home/me in the same
repostiory, /home is mounted from non-root filesystem, and a git operation
is done from inside /home/me/src.  But that is such a corner case we don't
want to give preference over helping people who will benefit from having
this default so that they do not have to suffer from slow automounters.

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

diff --git a/Documentation/git.txt b/Documentation/git.txt
index bf1b45eef1e1e2904cbcc1fcbd84528618a5dc1d..aa620832092590b7c29b47c53d85dd3a3fdb640e 100644 (file)
--- a/Documentation/git.txt
+++ b/Documentation/git.txt
@@ -531,10 +531,14 @@ git so take care if using Cogito etc.
        (Useful for excluding slow-loading network directories.)
 
 'GIT_ONE_FILESYSTEM'::
-       If set to a true value ("true" or a non-zero integer), stop at
-       filesystem boundaries when looking for a repository directory.
-       Like 'GIT_CEILING_DIRECTORIES', it will not affect an explicit
-       respository directory set via 'GIT_DIR' or on the command line.
+       When run in a directory that does not have ".git" repository
+       directory, git tries to find such a directory in the parent
+       directories to find the top of the working tree, but by default it
+       does not cross filesystem boundaries.  This environment variable
+       can be set to false value ("false" or zero) to tell git not to
+       stop at filesystem boundaries.  Like 'GIT_CEILING_DIRECTORIES',
+       this will not affect an explicit respository directory set via
+       'GIT_DIR' or on the command line.
 
 git Commits
 ~~~~~~~~~~~

diff --git a/setup.c b/setup.c
index 8b911b1a38f2a937ad6c2b69870f2c30872181dc..d29063349052757b9e57ed1312fd073399161393 100644 (file)
--- a/setup.c
+++ b/setup.c
@@ -323,7 +323,7 @@ const char *setup_git_directory_gently(int *nongit_ok)
        const char *gitdirenv;
        const char *gitfile_dir;
        int len, offset, ceil_offset, root_len;
-       int current_device = 0, one_filesystem = 0;
+       int current_device = 0, one_filesystem = 1;
        struct stat buf;
 
        /*
@@ -444,7 +444,7 @@ const char *setup_git_directory_gently(int *nongit_ok)
                                }
                                cwd[offset] = '\0';
                                die("Not a git repository (or any parent up to mount parent %s)\n"
-                                       "Stopping at filesystem boundary since GIT_ONE_FILESYSTEM is set.", cwd);
+                               "Stopping at filesystem boundary since GIT_ONE_FILESYSTEM is true.", cwd);
                        }
                }
                if (chdir("..")) {