t9300: document fast-import empty path issues

When given an empty path, fast-import sometimes reports "missing"
instead of using the root tree object.  On top of this, for "ls" and
file copy (but not move) it dies with "Empty path component found in
input".

Document this behaviour with failing test cases.

Reported-by: Dave Abrahams <dave@boostpro.com>
Signed-off-by: John Keeping <john@keeping.me.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/t/t9300-fast-import.sh b/t/t9300-fast-import.sh
index ac6f3b6af25c67ae3a2c0748c34f99b4cd0d4b32..f4b93557a6f76a9691ee81d57557d0c2192e5087 100755 (executable)
--- a/t/t9300-fast-import.sh
+++ b/t/t9300-fast-import.sh
@@ -1031,6 +1031,32 @@ test_expect_success \
         git diff-tree -M -r M3^ M3 >actual &&
         compare_diff_raw expect actual'
 
+cat >input <<INPUT_END
+commit refs/heads/M4
+committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
+data <<COMMIT
+rename root
+COMMIT
+
+from refs/heads/M2^0
+R "" sub
+
+INPUT_END
+
+cat >expect <<EOF
+:100644 100644 7123f7f44e39be127c5eb701e5968176ee9d78b1 7123f7f44e39be127c5eb701e5968176ee9d78b1 R100  file2/oldf      sub/file2/oldf
+:100755 100755 85df50785d62d3b05ab03d9cbf7e4a0b49449730 85df50785d62d3b05ab03d9cbf7e4a0b49449730 R100  file4   sub/file4
+:100755 100755 f1fb5da718392694d0076d677d6d0e364c79b0bc f1fb5da718392694d0076d677d6d0e364c79b0bc R100  i/am/new/to/you sub/i/am/new/to/you
+:100755 100755 e74b7d465e52746be2b4bae983670711e6e66657 e74b7d465e52746be2b4bae983670711e6e66657 R100  newdir/exec.sh  sub/newdir/exec.sh
+:100644 100644 fcf778cda181eaa1cbc9e9ce3a2e15ee9f9fe791 fcf778cda181eaa1cbc9e9ce3a2e15ee9f9fe791 R100  newdir/interesting      sub/newdir/interesting
+EOF
+test_expect_failure \
+       'M: rename root to subdirectory' \
+       'git fast-import <input &&
+        git diff-tree -M -r M4^ M4 >actual &&
+        cat actual &&
+        compare_diff_raw expect actual'
+
 ###
 ### series N
 ###
@@ -1227,6 +1253,29 @@ test_expect_success \
         git diff-tree -C --find-copies-harder -r N4 N6 >actual &&
         compare_diff_raw expect actual'
 
+test_expect_failure \
+       'N: copy root by path' \
+       'cat >expect <<-\EOF &&
+       :100755 100755 f1fb5da718392694d0076d677d6d0e364c79b0bc f1fb5da718392694d0076d677d6d0e364c79b0bc C100   file2/newf      oldroot/file2/newf
+       :100644 100644 7123f7f44e39be127c5eb701e5968176ee9d78b1 7123f7f44e39be127c5eb701e5968176ee9d78b1 C100   file2/oldf      oldroot/file2/oldf
+       :100755 100755 85df50785d62d3b05ab03d9cbf7e4a0b49449730 85df50785d62d3b05ab03d9cbf7e4a0b49449730 C100   file4   oldroot/file4
+       :100755 100755 e74b7d465e52746be2b4bae983670711e6e66657 e74b7d465e52746be2b4bae983670711e6e66657 C100   newdir/exec.sh  oldroot/newdir/exec.sh
+       :100644 100644 fcf778cda181eaa1cbc9e9ce3a2e15ee9f9fe791 fcf778cda181eaa1cbc9e9ce3a2e15ee9f9fe791 C100   newdir/interesting      oldroot/newdir/interesting
+       EOF
+        cat >input <<-INPUT_END &&
+       commit refs/heads/N-copy-root-path
+       committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
+       data <<COMMIT
+       copy root directory by (empty) path
+       COMMIT
+
+       from refs/heads/branch^0
+       C "" oldroot
+       INPUT_END
+        git fast-import <input &&
+        git diff-tree -C --find-copies-harder -r branch N-copy-root-path >actual &&
+        compare_diff_raw expect actual'
+
 test_expect_success \
        'N: delete directory by copying' \
        'cat >expect <<-\EOF &&
@@ -2934,4 +2983,20 @@ test_expect_success 'S: ls with garbage after sha1 must fail' '
        test_i18ngrep "space after tree-ish" err
 '
 
+###
+### series T (ls)
+###
+# Setup is carried over from series S.
+
+test_expect_failure 'T: ls root tree' '
+       sed -e "s/Z\$//" >expect <<-EOF &&
+       040000 tree $(git rev-parse S^{tree})   Z
+       EOF
+       sha1=$(git rev-parse --verify S) &&
+       git fast-import --import-marks=marks <<-EOF >actual &&
+       ls $sha1 ""
+       EOF
+       test_cmp expect actual
+'
+
 test_done