nixpkgs/pkgs/build-support/fetchpatch/default.nix
Naïm Favier bf7d13dc4f
fetchpatch: add relative
Allows restricting patches to a specific subdirectory, à la
`git diff --relative=subdir`.

This cannot be done (cleanly) currently because the `includes` logic
happens *after* `stripLen` is applied, so we can't match on `subdir/*`.

This change adds a `relative` argument that makes this possible by
filtering files before doing any processing, and setting `stripLen` and
`extraPrefix` accordingly.
2022-03-25 01:00:36 +01:00

84 lines
2.7 KiB
Nix

# This function downloads and normalizes a patch/diff file.
# This is primarily useful for dynamically generated patches,
# such as GitHub's or cgit's, where the non-significant content parts
# often change with updating of git or cgit.
# stripLen acts as the -p parameter when applying a patch.
{ lib, fetchurl, buildPackages }:
let
# 0.3.4 would change hashes: https://github.com/NixOS/nixpkgs/issues/25154
patchutils = buildPackages.patchutils_0_3_3;
in
{ relative ? null
, stripLen ? 0
, extraPrefix ? null
, excludes ? []
, includes ? []
, revert ? false
, postFetch ? ""
, ...
}@args:
let
args' = if relative != null then {
stripLen = 1 + lib.length (lib.splitString "/" relative) + stripLen;
extraPrefix = if extraPrefix != null then extraPrefix else "";
} else {
inherit stripLen extraPrefix;
};
in let
inherit (args') stripLen extraPrefix;
in
lib.throwIfNot (excludes == [] || includes == [])
"fetchpatch: cannot use excludes and includes simultaneously"
fetchurl ({
postFetch = ''
tmpfile="$TMPDIR/patch"
if [ ! -s "$out" ]; then
echo "error: Fetched patch file '$out' is empty!" 1>&2
exit 1
fi
"${patchutils}/bin/lsdiff" \
${lib.optionalString (relative != null) "-p1 -i ${lib.escapeShellArg relative}/'*'"} \
"$out" \
| sort -u | sed -e 's/[*?]/\\&/g' \
| xargs -I{} \
"${patchutils}/bin/filterdiff" \
--include={} \
--strip=${toString stripLen} \
${lib.optionalString (extraPrefix != null) ''
--addoldprefix=a/${lib.escapeShellArg extraPrefix} \
--addnewprefix=b/${lib.escapeShellArg extraPrefix} \
''} \
--clean "$out" > "$tmpfile"
if [ ! -s "$tmpfile" ]; then
echo "error: Normalized patch '$tmpfile' is empty (while the fetched file was not)!" 1>&2
echo "Did you maybe fetch a HTML representation of a patch instead of a raw patch?" 1>&2
echo "Fetched file was:" 1>&2
cat "$out" 1>&2
exit 1
fi
${patchutils}/bin/filterdiff \
-p1 \
${builtins.toString (builtins.map (x: "-x ${lib.escapeShellArg x}") excludes)} \
${builtins.toString (builtins.map (x: "-i ${lib.escapeShellArg x}") includes)} \
"$tmpfile" > "$out"
if [ ! -s "$out" ]; then
echo "error: Filtered patch '$out' is empty (while the original patch file was not)!" 1>&2
echo "Check your includes and excludes." 1>&2
echo "Normalized patch file was:" 1>&2
cat "$tmpfile" 1>&2
exit 1
fi
'' + lib.optionalString revert ''
${patchutils}/bin/interdiff "$out" /dev/null > "$tmpfile"
mv "$tmpfile" "$out"
'' + postFetch;
} // builtins.removeAttrs args [
"relative" "stripLen" "extraPrefix" "excludes" "includes" "revert" "postFetch"
])