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[PATCH] git-sh-setup: Fix scripts whose PWD is a symlink into a git work-dir

From
Marcel M. Cary <marcel@oak.homeunix.org>
Date
Dec 3, 2008, 05:27 UTC
Message-ID
<1228282020-2294-1-git-send-email-marcel@oak.homeunix.org>
In-Reply-To
<7vtz9vk6uj.fsf@gitster.siamese.dyndns.org>
* Before interpretting an upward path (../) in cd_to_toplevel,
  cd to a path without symlinks given by /bin/pwd
* Add tests for cd_to_toplevel and "git pull" in a symlinked
  directory that failed before this fix, plus constrasting
  scenarios that already worked
Signed-off-by: Marcel M. Cary <marcel@oak.homeunix.org>
---

I hope this patch will address concerns both about changes to existing APIs and speed of the new behavior.

A few notes on implementation choices:

I used /bin/pwd because of this precedent for choosing it over "cd -P" for compatibility. http://article.gmane.org/gmane.comp.version-control.git/46918

If cd_to_toplevel had concatenated $(/bin/pwd) with $cdup to avoid the separate "cd", it would require checking for $cdup being an absolute path. I wasn't sure how to check that in a way that is both portable and clearly faster than "cd", so cd_to_toplevel runs "cd" twice. I'm assuming that running an external command like expr or grep is slower than just doing the "cd".

cd_to_toplevel doesn't check $PWD to see whether to do the first cd, because some shells allegedly don't update it reliably.

Since cd_to_toplevel doesn't know whether it's at a symlinked PWD or not, I wrote it to treat the "cd $(/bin/pwd)" as mandatory, even when it might not actually be. So on systems without /bin/pwd, it will fail even when there are no symlinks. I thought that was better than inconsistent behavior depending on whether /bin/pwd is available.

The extra "cd" will be skipped when the script is already at the top of the working tree.

 git-sh-setup.sh           |   11 +++++++
 t/t2300-cd-to-toplevel.sh |   37 +++++++++++++++++++++++++
 t/t5521-pull-symlink.sh   |   67 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 115 insertions(+), 0 deletions(-)
 create mode 100755 t/t2300-cd-to-toplevel.sh
 create mode 100755 t/t5521-pull-symlink.sh
diff --git a/git-sh-setup.sh b/git-sh-setup.sh
index dbdf209..377700b 100755
--- a/git-sh-setup.sh
+++ b/git-sh-setup.sh
@@ -85,6 +85,17 @@ cd_to_toplevel () {
 	cdup=$(git rev-parse --show-cdup)
 	if test ! -z "$cdup"
 	then
+		# Interpret $cdup relative to the physical, not logical, cwd.
+		# Probably /bin/pwd is more portable than passing -P to cd or pwd.
+		phys="$(/bin/pwd)" || {
+			echo >&2 "Cannot determine the physical path to the current dir"
+			exit 1
+		}
+		cd "$phys" || {
+			echo >&2 "Cannot chdir to the physical path to current dir: $phys"
+			exit 1
+		}
+
 		cd "$cdup" || {
 			echo >&2 "Cannot chdir to $cdup, the toplevel of the working tree"
 			exit 1
diff --git a/t/t2300-cd-to-toplevel.sh b/t/t2300-cd-to-toplevel.sh
new file mode 100755
index 0000000..293dc35
--- /dev/null
+++ b/t/t2300-cd-to-toplevel.sh
@@ -0,0 +1,37 @@
+#!/bin/sh
+
+test_description='cd_to_toplevel'
+
+. ./test-lib.sh
+
+test_cd_to_toplevel () {
+	test_expect_success "$2" '
+		(
+			cd '"'$1'"' &&
+			. git-sh-setup &&
+			cd_to_toplevel &&
+			[ "$(pwd -P)" = "$TOPLEVEL" ]
+		)
+	'
+}
+
+TOPLEVEL="$(pwd -P)/repo"
+mkdir -p repo/sub/dir
+mv .git repo/
+SUBDIRECTORY_OK=1
+
+test_cd_to_toplevel repo 'at physical root'
+
+test_cd_to_toplevel repo/sub/dir 'at physical subdir'
+
+ln -s repo symrepo
+test_cd_to_toplevel symrepo 'at symbolic root'
+
+ln -s repo/sub/dir subdir-link
+test_cd_to_toplevel subdir-link 'at symbolic subdir'
+
+cd repo
+ln -s sub/dir internal-link
+test_cd_to_toplevel internal-link 'at internal symbolic subdir'
+
+test_done
diff --git a/t/t5521-pull-symlink.sh b/t/t5521-pull-symlink.sh
new file mode 100755
index 0000000..f18fec7
--- /dev/null
+++ b/t/t5521-pull-symlink.sh
@@ -0,0 +1,67 @@
+#!/bin/sh
+
+test_description='pulling from symlinked subdir'
+
+. ./test-lib.sh
+
+D=`pwd`
+
+# The scenario we are building:
+#
+#   trash\ directory/
+#     clone-repo/
+#       subdir/
+#         bar
+#     subdir-link -> clone-repo/subdir/
+#
+# The working directory is subdir-link.
+#
+test_expect_success setup '
+
+    mkdir subdir &&
+    touch subdir/bar &&
+    git add subdir/bar &&
+    git commit -m empty &&
+    git clone . clone-repo &&
+    # demonstrate that things work without the symlink
+    test_debug "cd clone-repo/subdir/ && git pull; cd ../.." &&
+    ln -s clone-repo/subdir/ subdir-link &&
+    cd subdir-link/ &&
+    test_debug "set +x"
+'
+
+# From subdir-link, pulling should work as it does from
+# clone-repo/subdir/.
+#
+# Instead, the error pull gave was:
+#
+#   fatal: 'origin': unable to chdir or not a git archive
+#   fatal: The remote end hung up unexpectedly
+#
+# because git would find the .git/config for the "trash directory"
+# repo, not for the clone-repo repo.  The "trash directory" repo
+# had no entry for origin.  Git found the wrong .git because
+# git rev-parse --show-cdup printed a path relative to
+# clone-repo/subdir/, not subdir-link/.  Git rev-parse --show-cdup
+# used the correct .git, but when the git pull shell script did
+# "cd `git rev-parse --show-cdup`", it ended up in the wrong
+# directory.  Shell "cd" works a little different from chdir() in C.
+# Bash's "cd -P" works like chdir() in C.
+#
+test_expect_success 'pulling from symlinked subdir' '
+
+    git pull
+'
+
+# Prove that the remote end really is a repo, and other commands
+# work fine in this context.
+#
+test_debug "
+    test_expect_success 'pushing from symlinked subdir' '
+
+        git push
+    '
+"
+cd "$D"
+
+test_done

-- 
1.6.0.3
Previous: Junio C HamanoNext: Junio C Hamano
Message 14 of 27 in “fixing git pull from symlinked directory”
  1. 0/2 fixing git pull from symlinked directoryMarcel M. Cary, Nov 15, 2008
  2. 1/2 Add failing test for "git pull" in symlinked directoryMarcel M. Cary, Nov 15, 2008
  3. 2/2 Support shell scripts that run from symlinks into a git working dirMarcel M. Cary, Nov 15, 2008
  4. rev-parse: Fix shell scripts whose cwd is a symlink into a git work-dirMarcel M. Cary, Nov 22, 2008
  5. Jakub NarebskiNov 22, 2008
  6. Andreas EricssonNov 23, 2008
  7. Marcel M. CaryNov 25, 2008
  8. Andreas EricssonNov 25, 2008
  9. Marcel M. CaryNov 25, 2008
  10. Johannes SixtNov 25, 2008
  11. Marcel M. CaryNov 25, 2008
  12. Johannes SixtNov 25, 2008
  13. Junio C HamanoNov 25, 2008
  14. git-sh-setup: Fix scripts whose PWD is a symlink into a git work-dirMarcel M. Cary, Dec 3, 2008
  15. Junio C HamanoDec 3, 2008
  16. git-sh-setup: Fix scripts whose PWD is a symlink into a git work-dirMarcel M. Cary, Dec 10, 2008
  17. Junio C HamanoDec 10, 2008
  18. git-sh-setup: Fix scripts whose PWD is a symlink into a git work-dirMarcel M. Cary, Dec 13, 2008
  19. Junio C HamanoDec 14, 2008
  20. git-sh-setup: Fix scripts whose PWD is a symlink into a git work-dirMarcel M. Cary, Dec 15, 2008
  21. Marcel M. CaryDec 15, 2008
  22. git-sh-setup: Use "cd" option, not /bin/pwd, for symlinked work treeMarcel M. Cary, Feb 7, 2009
  23. Johannes SchindelinFeb 7, 2009
  24. Marcel M. CaryFeb 8, 2009
  25. Johannes SchindelinFeb 8, 2009
  26. Marcel M. CaryFeb 11, 2009
  27. Jeff KingFeb 11, 2009

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