Re: Script to obliterate the most recent revision(s)

I filed https://issues.apache.org/jira/browse/SVN-4730, "'svnadmin
verify' should check rep-cache refers to valid revs".

The following script ("rollback-1.sh") incorporates some of your
suggestions:

[[[
#!/bin/bash
# Remove the most recent revision(s) from a repository
# usage: $0 NEW_HEAD_REV
# Assumes we are in the repository directory.
# Requires: svnadmin, svnlook

set -ex # stop on error; show cmds executed

# repository directory
REPOS=.

# desired new head revision
R=$1
OLD_R=`svnlook youngest $REPOS`
OLD_TXNS=`svnadmin lstxns $REPOS`

# check the repository format is one we know how to handle
test `cat $REPOS/format` -eq 5
test `cat $REPOS/db/fs-type` = fsfs
FSFS_FORMAT=`head -1 $REPOS/db/format`
test $FSFS_FORMAT -ge 7 # svn 1.9
test $FSFS_FORMAT -le 8 # svn 1.10
grep -q "layout sharded" db/format

# check the unwanted revisions have not been packed
# TODO: finish this:
svnadmin info $REPOS | grep "FSFS Shards Packed:" #...

# remove the 'current' file; let 'svnadmin recover' recreate it with the
# new head revision number later. (Alternatively, we could write $R into it.)
rm $REPOS/db/current

# remove the unwanted revision files
for F in $(seq $((R+1)) $OLD_R); do
  rm -f $REPOS/db/revs/*/$F $REPOS/db/revprops/*/$F
done

# remove all pending txns, in case they reference an unwanted rev
svnadmin rmtxns $REPOS $OLD_TXNS

# Prune the rep-cache. This is essential, otherwise later commits will be
# silently corrupted.
#
# 'svnadmin recover' does this since 1.7.3, 1.8.0.
#
# If we can't use 'recover' (e.g. because we're inside an 'svnadmin freeze'
# script) we could do this manually with the 'sqlite3' utility. The expected
# output is no output.
#sqlite3 $REPO/db/rep-cache.db "delete from rep_cache where revision > $R"

# re-start all repository-accessing processes (svnserve, httpd)
# TODO: invite the user to do that...

# 'recover' recreates the 'current' file according to the last rev found,
# and prunes the rep cache.
svnadmin recover $REPOS

]]]

- Julian