git-mv: fix moves into a subdir from outside

git-mv needs to be run from the base directory so that
the check if a file is under revision also covers files
outside of a subdirectory. Previously, e.g. in the git repo,

  cd Documentation; git-mv ../README .

produced the error

  Error: '../README' not under version control

The test is extended for this case; it previously only tested
one direction.

Signed-off-by: Josef Weidendorfer <Josef.Weidendorfer@gmx.de>
Signed-off-by: Junio C Hamano <junkio@cox.net>

git-mv.perl

@@ -62,9 +62,17 @@ else {
     $dstDir = "";
 }
 
+my $subdir_prefix = `git rev-parse --show-prefix`;
+chomp($subdir_prefix);
+
+# run in git base directory, so that git-ls-files lists all revisioned files
+chdir "$GIT_DIR/..";
+
 # normalize paths, needed to compare against versioned files and update-index
 # also, this is nicer to end-users by doing ".//a/./b/.//./c" ==> "a/b/c"
 for (@srcArgs, @dstArgs) {
+    # prepend git prefix as we run from base directory
+    $_ = $subdir_prefix.$_;
     s|^\./||;
     s|/\./|/| while (m|/\./|);
     s|//+|/|g;

t/t7001-mv.sh

@@ -11,17 +11,31 @@ test_expect_success \
      git-commit -m add -a'
 
 test_expect_success \
-    'moving the file' \
+    'moving the file out of subdirectory' \
     'cd path0 && git-mv COPYING ../path1/COPYING'
 
 # in path0 currently
 test_expect_success \
     'commiting the change' \
-    'cd .. && git-commit -m move -a'
+    'cd .. && git-commit -m move-out -a'
 
 test_expect_success \
     'checking the commit' \
     'git-diff-tree -r -M --name-status  HEAD^ HEAD | \
     grep -E "^R100.+path0/COPYING.+path1/COPYING"'
 
+test_expect_success \
+    'moving the file back into subdirectory' \
+    'cd path0 && git-mv ../path1/COPYING COPYING'
+
+# in path0 currently
+test_expect_success \
+    'commiting the change' \
+    'cd .. && git-commit -m move-in -a'
+
+test_expect_success \
+    'checking the commit' \
+    'git-diff-tree -r -M --name-status  HEAD^ HEAD | \
+    grep -E "^R100.+path1/COPYING.+path0/COPYING"'
+
 test_done