git-sh-setup: Use "cd" option, not /bin/pwd, for symlinked work tree

In cd_to_toplevel, instead of 'cd $(unset PWD; /bin/pwd)/$path'
use 'cd -P $path'.  The "-P" option yields a desirable similarity to
C chdir.

While the "-P" option may be slightly less commonly supported than
/bin/pwd, it is more concise, better tested, and less error prone.
I've already added the 'unset PWD' to fix the /bin/pwd solution on
BSD; there may be more edge cases out there.

This still passes all the same test cases in t5521-pull-symlink.sh and
t2300-cd-to-toplevel.sh, even before updating them to use 'pwd -P'.

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

diff --git a/git-sh-setup.sh b/git-sh-setup.sh
index 2142308..8382339 100755 (executable)
--- a/git-sh-setup.sh
+++ b/git-sh-setup.sh
@@ -85,27 +85,14 @@ cd_to_toplevel () {
        cdup=$(git rev-parse --show-cdup)
        if test ! -z "$cdup"
        then
-               case "$cdup" in
-               /*)
-                       # Not quite the same as if we did "cd -P '$cdup'" when
-                       # $cdup contains ".." after symlink path components.
-                       # Don't fix that case at least until Git switches to
-                       # "cd -P" across the board.
-                       phys="$cdup"
-                       ;;
-               ..|../*|*/..|*/../*)
-                       # Interpret $cdup relative to the physical, not logical, cwd.
-                       # Probably /bin/pwd is more portable than passing -P to cd or pwd.
-                       phys="$(unset PWD; /bin/pwd)/$cdup"
-                       ;;
-               *)
-                       # There's no "..", so no need to make things absolute.
-                       phys="$cdup"
-                       ;;
-               esac
-
-               cd "$phys" || {
-                       echo >&2 "Cannot chdir to $phys, the toplevel of the working tree"
+               # The "-P" option says to follow "physical" directory
+               # structure instead of following symbolic links.  When cdup is
+               # "../", this means following the ".." entry in the current
+               # directory instead textually removing a symlink path element
+               # from the PWD shell variable.  The "-P" behavior is more
+               # consistent with the C-style chdir used by most of Git.
+               cd -P "$cdup" || {
+                       echo >&2 "Cannot chdir to $cdup, the toplevel of the working tree"
                        exit 1
                }
        fi

diff --git a/t/t2300-cd-to-toplevel.sh b/t/t2300-cd-to-toplevel.sh
index e42cbfe..293dc35 100755 (executable)
--- a/t/t2300-cd-to-toplevel.sh
+++ b/t/t2300-cd-to-toplevel.sh
@@ -10,12 +10,12 @@ test_cd_to_toplevel () {
                        cd '"'$1'"' &&
                        . git-sh-setup &&
                        cd_to_toplevel &&
-                       [ "$(unset PWD; /bin/pwd)" = "$TOPLEVEL" ]
+                       [ "$(pwd -P)" = "$TOPLEVEL" ]
                )
        '
 }
 
-TOPLEVEL="$(unset PWD; /bin/pwd)/repo"
+TOPLEVEL="$(pwd -P)/repo"
 mkdir -p repo/sub/dir
 mv .git repo/
 SUBDIRECTORY_OK=1