[Quilt-dev] [PATCH] backup-files: Restore symbolic links

[Jean Delvare]

As "patch" originally did not handle symbolic links, backup-files
didn't have to care about them either. But now that git has
introduced an extended syntax which allows manipulating symbolic
links in patch files, "quilt push" may create or delete symbolic
links, which means that backup-files must support such operations
too.

Also extend the backup-files test case to cover these operations.

This fixes bug #59479:
https://savannah.nongnu.org/bugs/index.php?59479

Signed-off-by: Jean Delvare <jdelvare@suse.de>
---
 quilt/scripts/backup-files.in |   22 +++++++++++++---------
 test/backup-files.test        |   29 +++++++++++++++++++++++++++++
 2 files changed, 42 insertions(+), 9 deletions(-)

--- quilt.orig/quilt/scripts/backup-files.in    2019-04-15 08:57:43.755394855 
+0200
+++ quilt/quilt/scripts/backup-files.in 2020-11-18 15:32:48.224687161 +0100
@@ -110,24 +110,28 @@ restore()
        local file=$1
        local backup=$OPT_PREFIX$file
 
-       if [ ! -e "$backup" ]; then
+       if [ ! -L "$backup" -a ! -e "$backup" ]; then
                return 1
        fi
-       if [ -s "$backup" ]; then
+       if [ -L "$backup" -o -s "$backup" ]; then
                $ECHO "Restoring $file"
-               if [ -e "$file" ]; then
+               if [ -L "$file" -o -e "$file" ]; then
                        rm "$file"
                else
                        mkdir -p "$(dirname "$file")"
                fi
-               ln "$backup" "$file" 2>&4 || cp -p "$backup" "$file"
+               if [ -L "$backup" ]; then
+                       cp -P "$backup" "$file"
+               else
+                       ln "$backup" "$file" 2>&4 || cp -p "$backup" "$file"
+               fi
 
-               if [ -n "$OPT_TOUCH" ]; then
+               if [ -n "$OPT_TOUCH" -a ! -L "$file" ]; then
                        touch "$file"
                fi
        else
                $ECHO "Removing $file"
-               if [ -e "$file" ]; then
+               if [ -L "$file" -o -e "$file" ]; then
                        rm "$file"
                fi
        fi
@@ -149,7 +153,7 @@ restore_all()
 
        cd "$OPT_PREFIX"
        find . -type f -size 0 -print0 > "$EMPTY_FILES"
-       find . -type f -size +0 -print0 > "$NONEMPTY_FILES"
+       find . \( -type f -size +0 -o -type l \) -print0 > "$NONEMPTY_FILES"
        cd "$OLDPWD"
 
        if [ -s "$EMPTY_FILES" ]; then
@@ -164,7 +168,7 @@ restore_all()
                local target_dir=$PWD
 
                if (cd "$OPT_PREFIX" && \
-                   xargs -0 cp -l --parents --remove-destination \
+                   xargs -0 cp -Pl --parents --remove-destination \
                                --target-directory="$target_dir" \
                                < "$NONEMPTY_FILES" 2>&4); then
                        notify_action Restoring "$NONEMPTY_FILES"
@@ -185,7 +189,7 @@ restore_all()
                fi
 
                if [ -n "$OPT_TOUCH" ]; then
-                       xargs -0 touch -c < "$NONEMPTY_FILES"
+                       xargs -0 touch -ch < "$NONEMPTY_FILES"
                fi
        fi
 
--- quilt.orig/test/backup-files.test   2020-11-18 15:26:03.471924591 +0100
+++ quilt/test/backup-files.test        2020-11-18 15:33:53.223456181 +0100
@@ -229,3 +229,32 @@ Unit test of the backup-files script.
        > 1
        $ [ ! -s new ] || echo "file snapshot/new should be empty"
        $ rm -rf snapshot
+
+       # Test backup and restoration of a symbolic link
+       $ ln -s foo link
+       $ readlink link
+       > foo
+       $ %{QUILT_DIR}/scripts/backup-files -B backup/ -b link
+       > Copying link
+       $ readlink backup/link
+       > foo
+       $ rm -f link
+       $ %{QUILT_DIR}/scripts/backup-files -B backup/ -k -r link
+       > Restoring link
+       $ readlink link
+       > foo
+
+       # Same but reading from a file
+       $ rm -f link
+       $ %{QUILT_DIR}/scripts/backup-files -B backup/ -k -r -f -
+       < link
+       > Restoring link
+       $ readlink link
+       > foo
+
+       # Same but without specifying the file
+       $ rm -f link
+       $ %{QUILT_DIR}/scripts/backup-files -B backup/ -r -
+       > Restoring link
+       $ readlink link
+       > foo


-- 
Jean Delvare
SUSE L3 Support