File size: 3,277 Bytes
ac38b66 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 | """Write ablation variants of a unified diff: the patch minus some changed lines.
Usage: python3 ablate_patch.py PATCH OUTDIR [NAME=I,J,... ...]
Changed lines ('+' and '-' lines inside hunks) are numbered 1..N in patch
order. For each i, OUTDIR/L<i>.diff is the patch without changed line i.
Each NAME=I,J,... argument adds OUTDIR/<NAME>.diff without the listed
lines. Dropping a '+' line removes it; dropping a '-' line keeps the
original line as context. Hunk headers are recomputed, and hunks left with
no change are removed. OUTDIR/MANIFEST lists every variant and the lines
it drops.
"""
import re
import sys
from pathlib import Path
HUNK = re.compile(r"^@@ -(\d+)(?:,(\d+))? \+(\d+)(?:,(\d+))? @@(.*)$")
def parse(text):
"""Return a list of files: (header_lines, [(old_start, tail, body_lines)])."""
files, cur, hunk = [], None, None
for line in text.splitlines():
m = HUNK.match(line)
if line.startswith("diff --git"):
cur = ([line], [])
files.append(cur)
hunk = None
elif m:
hunk = (int(m.group(1)), m.group(5), [])
cur[1].append(hunk)
elif hunk is None:
cur[0].append(line)
else:
hunk[2].append(line)
return files
def render(files, drop):
out, idx = [], 0
for header, hunks in files:
body_out, delta = [], 0
for old_start, tail, body in hunks:
lines = []
for line in body:
if line[:1] in "+-":
idx += 1
if idx in drop:
if line[0] == "-":
lines.append(" " + line[1:])
continue
lines.append(line)
# trailing empty strings come from blank lines after the patch
while lines and lines[-1] == "":
lines.pop()
if not any(l[:1] in "+-" for l in lines):
continue
old_n = sum(1 for l in lines if l[:1] in " -" or l == "")
new_n = sum(1 for l in lines if l[:1] in " +" or l == "")
body_out.append(f"@@ -{old_start},{old_n} +{old_start + delta},{new_n} @@{tail}")
body_out.extend(lines)
delta += new_n - old_n
if body_out:
out.extend(header)
out.extend(body_out)
return "\n".join(out) + "\n"
def main():
patch, outdir = Path(sys.argv[1]), Path(sys.argv[2])
files = parse(patch.read_text())
changed = [l for _, hunks in files for _, _, body in hunks for l in body if l[:1] in "+-"]
outdir.mkdir(parents=True, exist_ok=True)
variants = [(f"L{i}", {i}) for i in range(1, len(changed) + 1)]
for arg in sys.argv[3:]:
name, idx = arg.split("=", 1)
variants.append((name, {int(x) for x in idx.split(",")}))
with open(outdir / "MANIFEST", "w") as man:
for i, line in enumerate(changed, 1):
man.write(f"line {i}: {line}\n")
for name, drop in variants:
(outdir / f"{name}.diff").write_text(render(files, drop))
man.write(f"{name}: drops {','.join(map(str, sorted(drop)))}\n")
print(f"{len(changed)} changed lines, {len(variants)} variants")
if __name__ == "__main__":
main()
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