Teach fast-import to recursively copy files/directories

Some source material (e.g. Subversion dump files) perform directory
renames by telling us the directory was copied, then deleted in the
same revision.  This makes it difficult for a frontend to convert
such data formats to a fast-import stream, as all the frontend has
on hand is "Copy a/ to b/; Delete a/" with no details about what
files are in a/, unless the frontend also kept track of all files.

The new 'C' subcommand within a commit allows the frontend to make a
recursive copy of one path to another path within the branch, without
needing to keep track of the individual file paths.  The metadata
copy is performed in memory efficiently, but is implemented as a
copy-immediately operation, rather than copy-on-write.

With this new 'C' subcommand frontends could obviously implement an
'R' (rename) on their own as a combination of 'C' and 'D' (delete),
but since we have already offered up 'R' in the past and it is a
trivial thing to keep implemented I'm not going to deprecate it.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

1 files changed, 83 insertions, 0 deletions

diff --git a/t/t9300-fast-import.sh b/t/t9300-fast-import.sh
index bf3720d..4b920be 100755
--- a/t/t9300-fast-import.sh
+++ b/t/t9300-fast-import.sh
@@ -648,4 +648,87 @@ test_expect_success \
 	 git diff-tree -M -r M3^ M3 >actual &&
 	 compare_diff_raw expect actual'
 
+###
+### series N
+###
+
+test_tick
+cat >input <<INPUT_END
+commit refs/heads/N1
+committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
+data <<COMMIT
+file copy
+COMMIT
+
+from refs/heads/branch^0
+C file2/newf file2/n.e.w.f
+
+INPUT_END
+
+cat >expect <<EOF
+:100755 100755 f1fb5da718392694d0076d677d6d0e364c79b0bc f1fb5da718392694d0076d677d6d0e364c79b0bc C100	file2/newf	file2/n.e.w.f
+EOF
+test_expect_success \
+	'N: copy file in same subdirectory' \
+	'git-fast-import <input &&
+	 git diff-tree -C --find-copies-harder -r N1^ N1 >actual &&
+	 compare_diff_raw expect actual'
+
+cat >input <<INPUT_END
+commit refs/heads/N2
+committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
+data <<COMMIT
+clean directory copy
+COMMIT
+
+from refs/heads/branch^0
+C file2 file3
+
+commit refs/heads/N2
+committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
+data <<COMMIT
+modify directory copy
+COMMIT
+
+M 644 inline file3/file5
+data <<EOF
+$file5_data
+EOF
+
+INPUT_END
+
+cat >expect <<EOF
+:100644 100644 fcf778cda181eaa1cbc9e9ce3a2e15ee9f9fe791 fcf778cda181eaa1cbc9e9ce3a2e15ee9f9fe791 C100	newdir/interesting	file3/file5
+:100755 100755 f1fb5da718392694d0076d677d6d0e364c79b0bc f1fb5da718392694d0076d677d6d0e364c79b0bc C100	file2/newf	file3/newf
+:100644 100644 7123f7f44e39be127c5eb701e5968176ee9d78b1 7123f7f44e39be127c5eb701e5968176ee9d78b1 C100	file2/oldf	file3/oldf
+EOF
+test_expect_success \
+	'N: copy then modify subdirectory' \
+	'git-fast-import <input &&
+	 git diff-tree -C --find-copies-harder -r N2^^ N2 >actual &&
+	 compare_diff_raw expect actual'
+
+cat >input <<INPUT_END
+commit refs/heads/N3
+committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
+data <<COMMIT
+dirty directory copy
+COMMIT
+
+from refs/heads/branch^0
+M 644 inline file2/file5
+data <<EOF
+$file5_data
+EOF
+
+C file2 file3
+D file2/file5
+
+INPUT_END
+
+test_expect_success \
+	'N: copy dirty subdirectory' \
+	'git-fast-import <input &&
+	 test `git-rev-parse N2^{tree}` = `git-rev-parse N3^{tree}`'
+
 test_done