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Make relative_path match full dir and not just a prefix
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Before this change, relative_path "/A/B/C" "/A/B/CD" would return "" instead of
the correct "../CD".
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erijo committed Dec 3, 2024
1 parent 6ee9b47 commit 362d326
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Showing 2 changed files with 52 additions and 52 deletions.
5 changes: 5 additions & 0 deletions test/test_unit_relative_path.py
Original file line number Diff line number Diff line change
Expand Up @@ -11,11 +11,16 @@
("/A/B/C", "/A/B/C", ""),
("/A/B/C", "/A/B/C/D", "D"),
("/A/B/C", "/A/B/C/D/E", "D/E"),
("/A/B/C", "/A/B/CD", "../CD"),
("/A/B/C", "/A/BB/C", "../../BB/C"),
("/A/B/C", "/A/B/D", "../D"),
("/A/B/C", "/A/B/D/E", "../D/E"),
("/A/B/C", "/A/D", "../../D"),
("/A/B/C", "/A/D/E", "../../D/E"),
("/A/B/C", "/D/E/F", "../../../D/E/F"),
("/", "/A/B/C", "A/B/C"),
("/A/B/C", "/", "../../.."),
("/A/B B/C", "/A/C C/D", "../../C C/D"),
],
)
def test_relative_path(runner, paths, base, full_path, expected):
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99 changes: 47 additions & 52 deletions yadm
Original file line number Diff line number Diff line change
Expand Up @@ -759,16 +759,13 @@ function alt_linking() {
}

function ln_relative() {
local full_source full_target target_dir
local full_source="$1"
local full_target="$2"
local target_dir="${full_target%/*}"
if [ "$target_dir" == "" ]; then
target_dir="/"
fi
local source="$1"
local target="$2"

local rel_source
rel_source=$(relative_path "$target_dir" "$full_source")
ln -nfs "$rel_source" "$full_target"
rel_source=$(relative_path "$(builtin_dirname "$target")" "$source")

ln -nfs "$rel_source" "$target"
alt_linked+=("$rel_source")
}

Expand Down Expand Up @@ -2004,61 +2001,59 @@ function parse_encrypt() {
function builtin_dirname() {
# dirname is not builtin, and universally available, this is a built-in
# replacement using parameter expansion
path="$1"
dname="${path%/*}"
if ! [[ "$path" =~ / ]]; then
echo "."
elif [ "$dname" = "" ]; then
echo "/"
else
echo "$dname"
local path="$1"
while [ "${path: -1}" = "/" ]; do
path="${path%/}"
done

local dir_name="${path%/*}"
while [ "${dir_name: -1}" = "/" ]; do
dir_name="${dir_name%/}"
done

if [ "$path" = "$dir_name" ]; then
dir_name="."
elif [ -z "$dir_name" ]; then
dir_name="/"
fi
echo "$dir_name"
}

function relative_path() {
# Output a path to $2/full, relative to $1/base
#
# This fucntion created with ideas from
# This function created with ideas from
# https://stackoverflow.com/questions/2564634
base="$1"
full="$2"

common_part="$base"
result=""

count=0
while [ "${full#"$common_part"}" == "${full}" ]; do
[ "$count" = "500" ] && return # this is a failsafe
# no match, means that candidate common part is not correct
# go up one level (reduce common part)
common_part="$(builtin_dirname "$common_part")"
# and record that we went back, with correct / handling
if [[ -z $result ]]; then
result=".."
else
result="../$result"
fi
count=$((count+1))
done
local base="$1"
if [ "${base:0:1}" != "/" ]; then
base="$PWD/$base"
fi

if [[ $common_part == "/" ]]; then
# special case for root (no common path)
result="$result/"
local full="$2"
if [ "${full:0:1}" != "/" ]; then
full="$PWD/$full"
fi

# since we now have identified the common part,
# compute the non-common part
forward_part="${full#"$common_part"}"
local common_part="$base"
local result=""

# and now stick all parts together
if [[ -n $result ]] && [[ -n $forward_part ]]; then
result="$result$forward_part"
elif [[ -n $forward_part ]]; then
# extra slash removal
result="${forward_part:1}"
fi
while [ "$common_part" != "$full" ]; do
if [ "$common_part" = "/" ]; then
# No common part found. Append / if result is set to make the final
# result correct.
result="${result:+$result/}"
break
elif [ "${full#"$common_part"/}" != "$full" ]; then
common_part="$common_part/"
result="${result:+$result/}"
break
fi
# Move to parent directory and update result
common_part=$(builtin_dirname "$common_part")
result="..${result:+/$result}"
done

echo "$result"
echo "$result${full#"$common_part"}"
}

# ****** Auto Functions ******
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