Added a comment: even git mv -f seems to work correctly

doc/todo/only_pass_unlocked_files_through_the_clean__47__smudge_filter/comment_3_51ea1a6c7c6c46322975cf051c191887._comment

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+[[!comment format=mdwn
+ username="Ilya_Shlyakhter"
+ avatar="http://cdn.libravatar.org/avatar/1647044369aa7747829c38b9dcc84df0"
+ subject="even git mv -f seems to work correctly"
+ date="2019-11-24T17:25:32Z"
+ content="""
+Also, `git mv` seems to reuse the already-smudged object contents of the source file for the target file, so even with `git mv -f` only the checksum gets checked into git:
+
+[[!format sh \"\"\"
++ cat ./test-git-mv
+#!/bin/bash
+
+set -eu -o pipefail -x
+
+cat $0
+
+TEST_DIR=/tmp/test_dir
+mkdir -p $TEST_DIR
+chmod -R u+w $TEST_DIR
+rm -rf $TEST_DIR
+mkdir -p $TEST_DIR
+pushd $TEST_DIR
+
+git init
+git annex init
+
+git --version
+git annex version
+
+rm .git/info/attributes
+echo foo > foo
+echo bar > bar
+git annex add foo bar
+git check-attr -a foo
+git check-attr -a bar
+echo 'bar filter=annex' > .gitattributes
+git add .gitattributes
+git check-attr -a foo
+git check-attr -a bar
+
+git annex unlock bar
+git mv bar foo  || true
+git mv -f bar foo
+git commit -m add
+git log -p
+
+
++ TEST_DIR=/tmp/test_dir
++ mkdir -p /tmp/test_dir
++ chmod -R u+w /tmp/test_dir
++ rm -rf /tmp/test_dir
++ mkdir -p /tmp/test_dir
++ pushd /tmp/test_dir
+/tmp/test_dir /tmp
++ git init
+Initialized empty Git repository in /tmp/test_dir/.git/
++ git annex init
+init  (scanning for unlocked files...)
+ok
+(recording state in git...)
++ git --version
+git version 2.20.1
++ git annex version
+git-annex version: 7.20191024-g6dc2272
+build flags: Assistant Webapp Pairing S3 WebDAV Inotify DBus DesktopNotify TorrentParser MagicMime Feeds Testsuite
+dependency versions: aws-0.21.1 bloomfilter-2.0.1.0 cryptonite-0.25 DAV-1.3.3 feed-1.0.1.0 ghc-8.6.5 http-client-0.5.14 persistent-sqlite-2.9.3 torrent-10000.1.1 uuid-1.3.13 yesod-1.6.0
+key/value backends: SHA256E SHA256 SHA512E SHA512 SHA224E SHA224 SHA384E SHA384 SHA3_256E SHA3_256 SHA3_512E SHA3_512 SHA3_224E SHA3_224 SHA3_384E SHA3_384 SKEIN256E SKEIN256 SKEIN512E SKEIN512 BLAKE2B256E BLAKE2B256 BLAKE2B512E BLAKE2B512 BLAKE2B160E BLAKE2B160 BLAKE2B224E BLAKE2B224 BLAKE2B384E BLAKE2B384 BLAKE2BP512E BLAKE2BP512 BLAKE2S256E BLAKE2S256 BLAKE2S160E BLAKE2S160 BLAKE2S224E BLAKE2S224 BLAKE2SP256E BLAKE2SP256 BLAKE2SP224E BLAKE2SP224 SHA1E SHA1 MD5E MD5 WORM URL
+remote types: git gcrypt p2p S3 bup directory rsync web bittorrent webdav adb tahoe glacier ddar git-lfs hook external
+operating system: linux x86_64
+supported repository versions: 7
+upgrade supported from repository versions: 0 1 2 3 4 5 6
+local repository version: 7
++ rm .git/info/attributes
++ echo foo
++ echo bar
++ git annex add foo bar
+add foo ok
+add bar ok
+(recording state in git...)
++ git check-attr -a foo
++ git check-attr -a bar
++ echo 'bar filter=annex'
++ git add .gitattributes
++ git check-attr -a foo
++ git check-attr -a bar
+bar: filter: annex
++ git annex unlock bar
+unlock bar ok
+(recording state in git...)
++ git mv bar foo
+fatal: destination exists, source=bar, destination=foo
++ true
++ git mv -f bar foo
++ git commit -m add
+[master (root-commit) 8610c0d] add
+ 2 files changed, 2 insertions(+)
+ create mode 100644 .gitattributes
+ create mode 100644 foo
++ git log -p
+commit 8610c0d8f327140608e71dc229f167731552d284
+Author: Ilya Shlyakhter <ilya_shl@alum.mit.edu>
+Date:   Sun Nov 24 12:24:28 2019 -0500
+
+    add
+
+diff --git a/.gitattributes b/.gitattributes
+new file mode 100644
+index 0000000..649f07e
+--- /dev/null
++++ b/.gitattributes
+@@ -0,0 +1 @@
++bar filter=annex
+diff --git a/foo b/foo
+new file mode 100644
+index 0000000..266ae50
+--- /dev/null
++++ b/foo
+@@ -0,0 +1 @@
++/annex/objects/MD5E-s4--c157a79031e1c40f85931829bc5fc552
+
+\"\"\"]]
+
+
+
+
+"""]]