Merge pull request #352 from Interlisp/restore-versions

Add small util for restoring versions from git history

scripts/restore-versions.sh

@@ -0,0 +1,134 @@
+#!/bin/sh
+
+# restore old versions from git repo
+# For use after a rm-versions or in a newly cloned repo
+# not guaranteed to return the SAME version as before
+# but it tries when it can.
+# version numbers follow git history
+
+
+# LC_ALL is needed for tr to keep it from getting confused
+export LC_ALL=C 
+
+file="$1"
+
+# If given a directory, restore all versions from that directory
+# There's a suble difference, bcause glob expansion won't try
+# to reversion .git .github at top level.
+
+if [ -d "$file" ]; then
+    for dir in "$file/"*[a-zA-Z0-9]
+    do echo restoring versions "$dir" && \
+	    find "$dir" -type f -iname "*[a-z0-9]" -exec "$0" {} \;
+    done
+    exit 0
+fi
+
+
+if [ ! -f "$file" ]; then
+    echo no such file "$file"
+    exit 1
+fi
+
+# file already has versions?
+
+for vfn in "$file".~[1-9]*~
+do if [ -f "$vfn" ]; then
+       echo "Already has versions: " $vfn && \
+	   exit 1
+   fi
+done
+
+
+#stash file and remember status
+#The $stash remembers if it did something or not
+
+stash=`git stash push -- $file 2>&1`
+
+
+# max is the maximum version checked in as as separate
+
+max=0
+
+# find commits with explicit old versions
+# In most cases there will be only one commit
+# these versions are restored, and n is set to 1+max of them
+# this is specific to our situation where we checked in some
+# ~nn~ versions and then .gitignore *~ was set 
+
+for commit in `git log --remove-empty --reverse --format="%h" -- "$file.~[1-9]*~"` 
+do git checkout -q $commit "$file.~[1-9]*~" 2>/dev/null && \
+   for version in "$file".~[1-9]*~
+   do  vn=`echo $version | sed 's/^.*\.~\([1-9][0-9]*\)~$/\1/'`
+       if [ ! -z $vn ]; then
+	   vn=`expr $vn + 1`  
+	   if [ $max -lt $vn ]; then
+	       max=$vn
+	   fi
+       fi
+   done
+done
+
+# if file and max version are the same, link them
+# this obsoletes medley-fix-links
+
+if cmp -q $file $file.~$max~ >/dev/null 2>&1
+then
+    rm $file.~$max~
+    ln $file $file.~$max~
+fi
+
+# $base is used to look for mentions of DSK versions
+base=`basename "$file" .LCOM`
+base=`basename "$base" .DFASL`
+pattern='{DSK}.*'"$base"'\.\?;[1-9][0-9]*'
+
+# Restore versions from git history. This process starts with
+# the max from the previous calculation and would go up by 1, but it
+# also prefers to restore files to their FILECREATED version
+# number. It does this by looking for {DSK}...root.~nn~ and using nn
+# as the version number if it isn't too small. It then makes a hard
+# link (each time for each commit) since the checkout will break any
+# old links
+
+n=`expr $max + 1`
+
+####
+# !!!! if you don't want these post-github versions
+# skip until end
+# If you want things before the last delete, remove the '--remove empty'
+####
+
+for commit in `git log --remove-empty --reverse --format="%h" -- "$file"`
+do git checkout -q $commit "$file" && \
+   fcv=`tr '\r' '\n' <"$file" | head -n 6 | grep -ai --max-count=1 --only-matching "$pattern"`
+   fcv=`echo $fcv | sed 's/^.*;\([1-9][0-9]*\)$/\1/'`
+   if [ ! -z $fcv ]; then
+       if [ $fcv -gt $n ]; then
+	   n=$fcv
+       fi
+   fi
+   ln "$file" "$file.~"$n"~" && n=`expr $n + 1`
+done
+
+### END SKIP
+
+# if the 'stash' at the beginning did something, restore the stashed file
+
+case $stash in
+    "error*" | "No local changes*") 
+	;;
+    "*")
+	git stash pop -- "$file" && \
+	ln $file "$file.~"$n"~" && n=`expr $n + 1`
+    ;;
+esac
+
+# if the result is only one version ;1 remove it
+# Otherwise, make sure no versions are staged
+if [ $n -eq 2 ]; then
+    rm -f "$file".~1~
+else
+    git restore --staged "$file.~[1-9]*~" 2>/dev/null
+fi
+