FA-75461 / Text diff and three-way merge / Open access
diff3 chunk merge: changes after the last stable line are dropped · case 01
Lines appended at the end of a file by either branch disappear from the merge.
ROOT CAUSE
The anchor list has no final sentinel, so the region after the last anchor is never merged.
VERIFIED REPAIR
Append a sentinel so the region after the last anchor is merged like any other.
Unsuccessful approach: Skipping the final region when base is exhausted still drops lines appended after the last base line.
Case contract
Match base against ours and against theirs with difflib.SequenceMatcher (autojunk off). Base lines matched on both sides are stable anchors. Between consecutive anchors (and after the last) compare the three regions: unchanged ours takes theirs, unchanged theirs takes ours, identical changes take ours, anything else is a conflict rendered as "<<<<<<< ours", ours, "||||||| base", base, "=======", theirs, ">>>>>>> theirs". Return merged lines and the conflict count.
Why this case matters
Three-way merge tools classify each region between stable lines to decide between clean merges and conflicts.
1 / The failure
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
import difflib
N = 1
observations = []
def solve(base, ours, theirs):
def matches(x):
sm = difflib.SequenceMatcher(None, base, x, autojunk=False)
mp = {}
for i, j, size in sm.get_matching_blocks():
for t in range(size):
mp[i + t] = j + t
return mp
mo, mt = matches(ours), matches(theirs)
out = []
conflicts = 0
i = j = k = 0
anchors = [bi for bi in range(len(base)) if bi in mo and bi in mt]
for bi in anchors:
if bi is None:
i1, j1, k1 = len(base), len(ours), len(theirs)
else:
i1, j1, k1 = bi, mo[bi], mt[bi]
B, O, T = base[i:i1], ours[j:j1], theirs[k:k1]
if O == B:
out.extend(T)
elif T == B:
out.extend(O)
elif O == T:
out.extend(O)
else:
conflicts += 1
out.append('<<<<<<< ours')
out.extend(O)
out.append('||||||| base')
out.extend(B)
out.append('=======')
out.extend(T)
out.append('>>>>>>> theirs')
if bi is not None:
out.append(base[bi])
i, j, k = i1 + 1, j1 + 1, k1 + 1
return {'merged': out, 'conflicts': conflicts}
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
cases = {
1: [('only ours changed', [['a', 'b', 'c', 'd', 'e'], ['a', 'B', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e']], {'merged': ['a', 'B', 'c', 'd', 'e'], 'conflicts': 0}), ('only theirs deleted a line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'd', 'e']], {'merged': ['a', 'b', 'd', 'e'], 'conflicts': 0}), ('both made the same change', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'C1', 'd', 'e'], ['a', 'b', 'C1', 'd', 'e']], {'merged': ['a', 'b', 'C1', 'd', 'e'], 'conflicts': 0}), ('both deleted the same line', [['a', 'b', 'c', 'd', 'e'], ['a', 'c', 'd', 'e'], ['a', 'c', 'd', 'e']], {'merged': ['a', 'c', 'd', 'e'], 'conflicts': 0}), ('conflicting edits', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'X', 'd', 'e'], ['a', 'b', 'Y', 'd', 'e']], {'merged': ['a', 'b', '<<<<<<< ours', 'X', '||||||| base', 'c', '=======', 'Y', '>>>>>>> theirs', 'd', 'e'], 'conflicts': 1}), ('changes after the last stable line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e', 'o0'], ['a', 'b', 'c', 'd', 'e', 'T']], {'merged': ['a', 'b', 'c', 'd', 'e', '<<<<<<< ours', 'o0', '||||||| base', '=======', 'T', '>>>>>>> theirs'], 'conflicts': 1}), ('appended by one side only', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e', 't0']], {'merged': ['a', 'b', 'c', 'd', 'e', 't0'], 'conflicts': 0}), ('changes on both sides in different places', [['a', 'b', 'c', 'd', 'e'], ['A', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'D', 'e']], {'merged': ['A', 'b', 'c', 'D', 'e'], 'conflicts': 0}), ('theirs changes the last base line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'E']], {'merged': ['a', 'b', 'c', 'd', 'E'], 'conflicts': 0})],
2: [('only ours changed', [['a', 'b', 'c', 'd', 'e'], ['a', 'B', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e']], {'merged': ['a', 'B', 'c', 'd', 'e'], 'conflicts': 0}), ('only theirs deleted a line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'd', 'e']], {'merged': ['a', 'b', 'd', 'e'], 'conflicts': 0}), ('both made the same change', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'C2', 'd', 'e'], ['a', 'b', 'C2', 'd', 'e']], {'merged': ['a', 'b', 'C2', 'd', 'e'], 'conflicts': 0}), ('both deleted the same line', [['a', 'b', 'c', 'd', 'e'], ['a', 'c', 'd', 'e'], ['a', 'c', 'd', 'e']], {'merged': ['a', 'c', 'd', 'e'], 'conflicts': 0}), ('conflicting edits', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'X', 'd', 'e'], ['a', 'b', 'Y', 'd', 'e']], {'merged': ['a', 'b', '<<<<<<< ours', 'X', '||||||| base', 'c', '=======', 'Y', '>>>>>>> theirs', 'd', 'e'], 'conflicts': 1}), ('changes after the last stable line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e', 'o0', 'o1'], ['a', 'b', 'c', 'd', 'e', 'T']], {'merged': ['a', 'b', 'c', 'd', 'e', '<<<<<<< ours', 'o0', 'o1', '||||||| base', '=======', 'T', '>>>>>>> theirs'], 'conflicts': 1}), ('appended by one side only', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e', 't0', 't1']], {'merged': ['a', 'b', 'c', 'd', 'e', 't0', 't1'], 'conflicts': 0}), ('changes on both sides in different places', [['a', 'b', 'c', 'd', 'e'], ['A', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'D', 'e']], {'merged': ['A', 'b', 'c', 'D', 'e'], 'conflicts': 0}), ('theirs changes the last base line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'E']], {'merged': ['a', 'b', 'c', 'd', 'E'], 'conflicts': 0})],
3: [('only ours changed', [['a', 'b', 'c', 'd', 'e'], ['a', 'B', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e']], {'merged': ['a', 'B', 'c', 'd', 'e'], 'conflicts': 0}), ('only theirs deleted a line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'd', 'e']], {'merged': ['a', 'b', 'd', 'e'], 'conflicts': 0}), ('both made the same change', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'C3', 'd', 'e'], ['a', 'b', 'C3', 'd', 'e']], {'merged': ['a', 'b', 'C3', 'd', 'e'], 'conflicts': 0}), ('both deleted the same line', [['a', 'b', 'c', 'd', 'e'], ['a', 'c', 'd', 'e'], ['a', 'c', 'd', 'e']], {'merged': ['a', 'c', 'd', 'e'], 'conflicts': 0}), ('conflicting edits', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'X', 'd', 'e'], ['a', 'b', 'Y', 'd', 'e']], {'merged': ['a', 'b', '<<<<<<< ours', 'X', '||||||| base', 'c', '=======', 'Y', '>>>>>>> theirs', 'd', 'e'], 'conflicts': 1}), ('changes after the last stable line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e', 'o0', 'o1', 'o2'], ['a', 'b', 'c', 'd', 'e', 'T']], {'merged': ['a', 'b', 'c', 'd', 'e', '<<<<<<< ours', 'o0', 'o1', 'o2', '||||||| base', '=======', 'T', '>>>>>>> theirs'], 'conflicts': 1}), ('appended by one side only', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e', 't0', 't1', 't2']], {'merged': ['a', 'b', 'c', 'd', 'e', 't0', 't1', 't2'], 'conflicts': 0}), ('changes on both sides in different places', [['a', 'b', 'c', 'd', 'e'], ['A', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'D', 'e']], {'merged': ['A', 'b', 'c', 'D', 'e'], 'conflicts': 0}), ('theirs changes the last base line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'E']], {'merged': ['a', 'b', 'c', 'd', 'E'], 'conflicts': 0})],
4: [('only ours changed', [['a', 'b', 'c', 'd', 'e'], ['a', 'B', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e']], {'merged': ['a', 'B', 'c', 'd', 'e'], 'conflicts': 0}), ('only theirs deleted a line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'd', 'e']], {'merged': ['a', 'b', 'd', 'e'], 'conflicts': 0}), ('both made the same change', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'C4', 'd', 'e'], ['a', 'b', 'C4', 'd', 'e']], {'merged': ['a', 'b', 'C4', 'd', 'e'], 'conflicts': 0}), ('both deleted the same line', [['a', 'b', 'c', 'd', 'e'], ['a', 'c', 'd', 'e'], ['a', 'c', 'd', 'e']], {'merged': ['a', 'c', 'd', 'e'], 'conflicts': 0}), ('conflicting edits', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'X', 'd', 'e'], ['a', 'b', 'Y', 'd', 'e']], {'merged': ['a', 'b', '<<<<<<< ours', 'X', '||||||| base', 'c', '=======', 'Y', '>>>>>>> theirs', 'd', 'e'], 'conflicts': 1}), ('changes after the last stable line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e', 'o0', 'o1', 'o2', 'o3'], ['a', 'b', 'c', 'd', 'e', 'T']], {'merged': ['a', 'b', 'c', 'd', 'e', '<<<<<<< ours', 'o0', 'o1', 'o2', 'o3', '||||||| base', '=======', 'T', '>>>>>>> theirs'], 'conflicts': 1}), ('appended by one side only', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e', 't0', 't1', 't2', 't3']], {'merged': ['a', 'b', 'c', 'd', 'e', 't0', 't1', 't2', 't3'], 'conflicts': 0}), ('changes on both sides in different places', [['a', 'b', 'c', 'd', 'e'], ['A', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'D', 'e']], {'merged': ['A', 'b', 'c', 'D', 'e'], 'conflicts': 0}), ('theirs changes the last base line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'E']], {'merged': ['a', 'b', 'c', 'd', 'E'], 'conflicts': 0})],
5: [('only ours changed', [['a', 'b', 'c', 'd', 'e'], ['a', 'B', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e']], {'merged': ['a', 'B', 'c', 'd', 'e'], 'conflicts': 0}), ('only theirs deleted a line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'd', 'e']], {'merged': ['a', 'b', 'd', 'e'], 'conflicts': 0}), ('both made the same change', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'C5', 'd', 'e'], ['a', 'b', 'C5', 'd', 'e']], {'merged': ['a', 'b', 'C5', 'd', 'e'], 'conflicts': 0}), ('both deleted the same line', [['a', 'b', 'c', 'd', 'e'], ['a', 'c', 'd', 'e'], ['a', 'c', 'd', 'e']], {'merged': ['a', 'c', 'd', 'e'], 'conflicts': 0}), ('conflicting edits', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'X', 'd', 'e'], ['a', 'b', 'Y', 'd', 'e']], {'merged': ['a', 'b', '<<<<<<< ours', 'X', '||||||| base', 'c', '=======', 'Y', '>>>>>>> theirs', 'd', 'e'], 'conflicts': 1}), ('changes after the last stable line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e', 'o0', 'o1', 'o2', 'o3', 'o4'], ['a', 'b', 'c', 'd', 'e', 'T']], {'merged': ['a', 'b', 'c', 'd', 'e', '<<<<<<< ours', 'o0', 'o1', 'o2', 'o3', 'o4', '||||||| base', '=======', 'T', '>>>>>>> theirs'], 'conflicts': 1}), ('appended by one side only', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e', 't0', 't1', 't2', 't3', 't4']], {'merged': ['a', 'b', 'c', 'd', 'e', 't0', 't1', 't2', 't3', 't4'], 'conflicts': 0}), ('changes on both sides in different places', [['a', 'b', 'c', 'd', 'e'], ['A', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'D', 'e']], {'merged': ['A', 'b', 'c', 'D', 'e'], 'conflicts': 0}), ('theirs changes the last base line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'E']], {'merged': ['a', 'b', 'c', 'd', 'E'], 'conflicts': 0})],
}[N]
for label, args, expected in cases:
check(label, solve(*args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
| Boundary fixture | Actual | Expected | Outcome |
|---|---|---|---|
| only ours changed | {'conflicts': 0, 'merged': ['a', 'B', 'c', 'd', 'e']} | {'conflicts': 0, 'merged': ['a', 'B', 'c', 'd', 'e']} | Passed |
| only theirs deleted a line | {'conflicts': 0, 'merged': ['a', 'b', 'd', 'e']} | {'conflicts': 0, 'merged': ['a', 'b', 'd', 'e']} | Passed |
| both made the same change | {'conflicts': 0, 'merged': ['a', 'b', 'C1', 'd', 'e']} | {'conflicts': 0, 'merged': ['a', 'b', 'C1', 'd', 'e']} | Passed |
| both deleted the same line | {'conflicts': 0, 'merged': ['a', 'c', 'd', 'e']} | {'conflicts': 0, 'merged': ['a', 'c', 'd', 'e']} | Passed |
| conflicting edits | {'conflicts': 1, 'merged': ['a', 'b', '<<<<<<< ours', 'X', '||||||| base', 'c', '=======', 'Y', '>>>>>>> theirs', 'd', 'e']} | {'conflicts': 1, 'merged': ['a', 'b', '<<<<<<< ours', 'X', '||||||| base', 'c', '=======', 'Y', '>>>>>>> theirs', 'd', 'e']} | Passed |
| changes after the last stable line | {'conflicts': 0, 'merged': ['a', 'b', 'c', 'd', 'e']} | {'conflicts': 1, 'merged': ['a', 'b', 'c', 'd', 'e', '<<<<<<< ours', 'o0', '||||||| base', '=======', 'T', '>>>>>>> theirs']} | Failed |
| appended by one side only | {'conflicts': 0, 'merged': ['a', 'b', 'c', 'd', 'e']} | {'conflicts': 0, 'merged': ['a', 'b', 'c', 'd', 'e', 't0']} | Failed |
| changes on both sides in different places | {'conflicts': 0, 'merged': ['A', 'b', 'c', 'D', 'e']} | {'conflicts': 0, 'merged': ['A', 'b', 'c', 'D', 'e']} | Passed |
| theirs changes the last base line | {'conflicts': 0, 'merged': ['a', 'b', 'c', 'd']} | {'conflicts': 0, 'merged': ['a', 'b', 'c', 'd', 'E']} | Failed |
SHA-256 / 059b68c7e92bc76a88aa20ad3cee44d8c63358322c19264165ee1b11f17dcc8a
2 / The unsuccessful fix
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
import difflib
N = 1
observations = []
def solve(base, ours, theirs):
def matches(x):
sm = difflib.SequenceMatcher(None, base, x, autojunk=False)
mp = {}
for i, j, size in sm.get_matching_blocks():
for t in range(size):
mp[i + t] = j + t
return mp
mo, mt = matches(ours), matches(theirs)
out = []
conflicts = 0
i = j = k = 0
anchors = [bi for bi in range(len(base)) if bi in mo and bi in mt] + [None]
for bi in anchors:
if bi is None:
if i >= len(base):
break
i1, j1, k1 = len(base), len(ours), len(theirs)
else:
i1, j1, k1 = bi, mo[bi], mt[bi]
B, O, T = base[i:i1], ours[j:j1], theirs[k:k1]
if O == B:
out.extend(T)
elif T == B:
out.extend(O)
elif O == T:
out.extend(O)
else:
conflicts += 1
out.append('<<<<<<< ours')
out.extend(O)
out.append('||||||| base')
out.extend(B)
out.append('=======')
out.extend(T)
out.append('>>>>>>> theirs')
if bi is not None:
out.append(base[bi])
i, j, k = i1 + 1, j1 + 1, k1 + 1
return {'merged': out, 'conflicts': conflicts}
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
cases = {
1: [('only ours changed', [['a', 'b', 'c', 'd', 'e'], ['a', 'B', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e']], {'merged': ['a', 'B', 'c', 'd', 'e'], 'conflicts': 0}), ('only theirs deleted a line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'd', 'e']], {'merged': ['a', 'b', 'd', 'e'], 'conflicts': 0}), ('both made the same change', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'C1', 'd', 'e'], ['a', 'b', 'C1', 'd', 'e']], {'merged': ['a', 'b', 'C1', 'd', 'e'], 'conflicts': 0}), ('both deleted the same line', [['a', 'b', 'c', 'd', 'e'], ['a', 'c', 'd', 'e'], ['a', 'c', 'd', 'e']], {'merged': ['a', 'c', 'd', 'e'], 'conflicts': 0}), ('conflicting edits', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'X', 'd', 'e'], ['a', 'b', 'Y', 'd', 'e']], {'merged': ['a', 'b', '<<<<<<< ours', 'X', '||||||| base', 'c', '=======', 'Y', '>>>>>>> theirs', 'd', 'e'], 'conflicts': 1}), ('changes after the last stable line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e', 'o0'], ['a', 'b', 'c', 'd', 'e', 'T']], {'merged': ['a', 'b', 'c', 'd', 'e', '<<<<<<< ours', 'o0', '||||||| base', '=======', 'T', '>>>>>>> theirs'], 'conflicts': 1}), ('appended by one side only', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e', 't0']], {'merged': ['a', 'b', 'c', 'd', 'e', 't0'], 'conflicts': 0}), ('changes on both sides in different places', [['a', 'b', 'c', 'd', 'e'], ['A', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'D', 'e']], {'merged': ['A', 'b', 'c', 'D', 'e'], 'conflicts': 0}), ('theirs changes the last base line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'E']], {'merged': ['a', 'b', 'c', 'd', 'E'], 'conflicts': 0})],
2: [('only ours changed', [['a', 'b', 'c', 'd', 'e'], ['a', 'B', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e']], {'merged': ['a', 'B', 'c', 'd', 'e'], 'conflicts': 0}), ('only theirs deleted a line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'd', 'e']], {'merged': ['a', 'b', 'd', 'e'], 'conflicts': 0}), ('both made the same change', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'C2', 'd', 'e'], ['a', 'b', 'C2', 'd', 'e']], {'merged': ['a', 'b', 'C2', 'd', 'e'], 'conflicts': 0}), ('both deleted the same line', [['a', 'b', 'c', 'd', 'e'], ['a', 'c', 'd', 'e'], ['a', 'c', 'd', 'e']], {'merged': ['a', 'c', 'd', 'e'], 'conflicts': 0}), ('conflicting edits', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'X', 'd', 'e'], ['a', 'b', 'Y', 'd', 'e']], {'merged': ['a', 'b', '<<<<<<< ours', 'X', '||||||| base', 'c', '=======', 'Y', '>>>>>>> theirs', 'd', 'e'], 'conflicts': 1}), ('changes after the last stable line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e', 'o0', 'o1'], ['a', 'b', 'c', 'd', 'e', 'T']], {'merged': ['a', 'b', 'c', 'd', 'e', '<<<<<<< ours', 'o0', 'o1', '||||||| base', '=======', 'T', '>>>>>>> theirs'], 'conflicts': 1}), ('appended by one side only', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e', 't0', 't1']], {'merged': ['a', 'b', 'c', 'd', 'e', 't0', 't1'], 'conflicts': 0}), ('changes on both sides in different places', [['a', 'b', 'c', 'd', 'e'], ['A', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'D', 'e']], {'merged': ['A', 'b', 'c', 'D', 'e'], 'conflicts': 0}), ('theirs changes the last base line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'E']], {'merged': ['a', 'b', 'c', 'd', 'E'], 'conflicts': 0})],
3: [('only ours changed', [['a', 'b', 'c', 'd', 'e'], ['a', 'B', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e']], {'merged': ['a', 'B', 'c', 'd', 'e'], 'conflicts': 0}), ('only theirs deleted a line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'd', 'e']], {'merged': ['a', 'b', 'd', 'e'], 'conflicts': 0}), ('both made the same change', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'C3', 'd', 'e'], ['a', 'b', 'C3', 'd', 'e']], {'merged': ['a', 'b', 'C3', 'd', 'e'], 'conflicts': 0}), ('both deleted the same line', [['a', 'b', 'c', 'd', 'e'], ['a', 'c', 'd', 'e'], ['a', 'c', 'd', 'e']], {'merged': ['a', 'c', 'd', 'e'], 'conflicts': 0}), ('conflicting edits', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'X', 'd', 'e'], ['a', 'b', 'Y', 'd', 'e']], {'merged': ['a', 'b', '<<<<<<< ours', 'X', '||||||| base', 'c', '=======', 'Y', '>>>>>>> theirs', 'd', 'e'], 'conflicts': 1}), ('changes after the last stable line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e', 'o0', 'o1', 'o2'], ['a', 'b', 'c', 'd', 'e', 'T']], {'merged': ['a', 'b', 'c', 'd', 'e', '<<<<<<< ours', 'o0', 'o1', 'o2', '||||||| base', '=======', 'T', '>>>>>>> theirs'], 'conflicts': 1}), ('appended by one side only', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e', 't0', 't1', 't2']], {'merged': ['a', 'b', 'c', 'd', 'e', 't0', 't1', 't2'], 'conflicts': 0}), ('changes on both sides in different places', [['a', 'b', 'c', 'd', 'e'], ['A', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'D', 'e']], {'merged': ['A', 'b', 'c', 'D', 'e'], 'conflicts': 0}), ('theirs changes the last base line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'E']], {'merged': ['a', 'b', 'c', 'd', 'E'], 'conflicts': 0})],
4: [('only ours changed', [['a', 'b', 'c', 'd', 'e'], ['a', 'B', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e']], {'merged': ['a', 'B', 'c', 'd', 'e'], 'conflicts': 0}), ('only theirs deleted a line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'd', 'e']], {'merged': ['a', 'b', 'd', 'e'], 'conflicts': 0}), ('both made the same change', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'C4', 'd', 'e'], ['a', 'b', 'C4', 'd', 'e']], {'merged': ['a', 'b', 'C4', 'd', 'e'], 'conflicts': 0}), ('both deleted the same line', [['a', 'b', 'c', 'd', 'e'], ['a', 'c', 'd', 'e'], ['a', 'c', 'd', 'e']], {'merged': ['a', 'c', 'd', 'e'], 'conflicts': 0}), ('conflicting edits', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'X', 'd', 'e'], ['a', 'b', 'Y', 'd', 'e']], {'merged': ['a', 'b', '<<<<<<< ours', 'X', '||||||| base', 'c', '=======', 'Y', '>>>>>>> theirs', 'd', 'e'], 'conflicts': 1}), ('changes after the last stable line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e', 'o0', 'o1', 'o2', 'o3'], ['a', 'b', 'c', 'd', 'e', 'T']], {'merged': ['a', 'b', 'c', 'd', 'e', '<<<<<<< ours', 'o0', 'o1', 'o2', 'o3', '||||||| base', '=======', 'T', '>>>>>>> theirs'], 'conflicts': 1}), ('appended by one side only', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e', 't0', 't1', 't2', 't3']], {'merged': ['a', 'b', 'c', 'd', 'e', 't0', 't1', 't2', 't3'], 'conflicts': 0}), ('changes on both sides in different places', [['a', 'b', 'c', 'd', 'e'], ['A', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'D', 'e']], {'merged': ['A', 'b', 'c', 'D', 'e'], 'conflicts': 0}), ('theirs changes the last base line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'E']], {'merged': ['a', 'b', 'c', 'd', 'E'], 'conflicts': 0})],
5: [('only ours changed', [['a', 'b', 'c', 'd', 'e'], ['a', 'B', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e']], {'merged': ['a', 'B', 'c', 'd', 'e'], 'conflicts': 0}), ('only theirs deleted a line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'd', 'e']], {'merged': ['a', 'b', 'd', 'e'], 'conflicts': 0}), ('both made the same change', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'C5', 'd', 'e'], ['a', 'b', 'C5', 'd', 'e']], {'merged': ['a', 'b', 'C5', 'd', 'e'], 'conflicts': 0}), ('both deleted the same line', [['a', 'b', 'c', 'd', 'e'], ['a', 'c', 'd', 'e'], ['a', 'c', 'd', 'e']], {'merged': ['a', 'c', 'd', 'e'], 'conflicts': 0}), ('conflicting edits', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'X', 'd', 'e'], ['a', 'b', 'Y', 'd', 'e']], {'merged': ['a', 'b', '<<<<<<< ours', 'X', '||||||| base', 'c', '=======', 'Y', '>>>>>>> theirs', 'd', 'e'], 'conflicts': 1}), ('changes after the last stable line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e', 'o0', 'o1', 'o2', 'o3', 'o4'], ['a', 'b', 'c', 'd', 'e', 'T']], {'merged': ['a', 'b', 'c', 'd', 'e', '<<<<<<< ours', 'o0', 'o1', 'o2', 'o3', 'o4', '||||||| base', '=======', 'T', '>>>>>>> theirs'], 'conflicts': 1}), ('appended by one side only', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e', 't0', 't1', 't2', 't3', 't4']], {'merged': ['a', 'b', 'c', 'd', 'e', 't0', 't1', 't2', 't3', 't4'], 'conflicts': 0}), ('changes on both sides in different places', [['a', 'b', 'c', 'd', 'e'], ['A', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'D', 'e']], {'merged': ['A', 'b', 'c', 'D', 'e'], 'conflicts': 0}), ('theirs changes the last base line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'E']], {'merged': ['a', 'b', 'c', 'd', 'E'], 'conflicts': 0})],
}[N]
for label, args, expected in cases:
check(label, solve(*args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
| Boundary fixture | Actual | Expected | Outcome |
|---|---|---|---|
| only ours changed | {'conflicts': 0, 'merged': ['a', 'B', 'c', 'd', 'e']} | {'conflicts': 0, 'merged': ['a', 'B', 'c', 'd', 'e']} | Passed |
| only theirs deleted a line | {'conflicts': 0, 'merged': ['a', 'b', 'd', 'e']} | {'conflicts': 0, 'merged': ['a', 'b', 'd', 'e']} | Passed |
| both made the same change | {'conflicts': 0, 'merged': ['a', 'b', 'C1', 'd', 'e']} | {'conflicts': 0, 'merged': ['a', 'b', 'C1', 'd', 'e']} | Passed |
| both deleted the same line | {'conflicts': 0, 'merged': ['a', 'c', 'd', 'e']} | {'conflicts': 0, 'merged': ['a', 'c', 'd', 'e']} | Passed |
| conflicting edits | {'conflicts': 1, 'merged': ['a', 'b', '<<<<<<< ours', 'X', '||||||| base', 'c', '=======', 'Y', '>>>>>>> theirs', 'd', 'e']} | {'conflicts': 1, 'merged': ['a', 'b', '<<<<<<< ours', 'X', '||||||| base', 'c', '=======', 'Y', '>>>>>>> theirs', 'd', 'e']} | Passed |
| changes after the last stable line | {'conflicts': 0, 'merged': ['a', 'b', 'c', 'd', 'e']} | {'conflicts': 1, 'merged': ['a', 'b', 'c', 'd', 'e', '<<<<<<< ours', 'o0', '||||||| base', '=======', 'T', '>>>>>>> theirs']} | Failed |
| appended by one side only | {'conflicts': 0, 'merged': ['a', 'b', 'c', 'd', 'e']} | {'conflicts': 0, 'merged': ['a', 'b', 'c', 'd', 'e', 't0']} | Failed |
| changes on both sides in different places | {'conflicts': 0, 'merged': ['A', 'b', 'c', 'D', 'e']} | {'conflicts': 0, 'merged': ['A', 'b', 'c', 'D', 'e']} | Passed |
| theirs changes the last base line | {'conflicts': 0, 'merged': ['a', 'b', 'c', 'd', 'E']} | {'conflicts': 0, 'merged': ['a', 'b', 'c', 'd', 'E']} | Passed |
SHA-256 / 7d98ec13a5ea647660f66a7db121d988005ea7c37b6fcd6e9919c7fa6fbd0439
3 / The verified repair
Exit 0"""Failure Map reference implementation. Python standard library only."""
import json
import difflib
N = 1
observations = []
def solve(base, ours, theirs):
def matches(x):
sm = difflib.SequenceMatcher(None, base, x, autojunk=False)
mp = {}
for i, j, size in sm.get_matching_blocks():
for t in range(size):
mp[i + t] = j + t
return mp
mo, mt = matches(ours), matches(theirs)
out = []
conflicts = 0
i = j = k = 0
anchors = [bi for bi in range(len(base)) if bi in mo and bi in mt] + [None]
for bi in anchors:
if bi is None:
i1, j1, k1 = len(base), len(ours), len(theirs)
else:
i1, j1, k1 = bi, mo[bi], mt[bi]
B, O, T = base[i:i1], ours[j:j1], theirs[k:k1]
if O == B:
out.extend(T)
elif T == B:
out.extend(O)
elif O == T:
out.extend(O)
else:
conflicts += 1
out.append('<<<<<<< ours')
out.extend(O)
out.append('||||||| base')
out.extend(B)
out.append('=======')
out.extend(T)
out.append('>>>>>>> theirs')
if bi is not None:
out.append(base[bi])
i, j, k = i1 + 1, j1 + 1, k1 + 1
return {'merged': out, 'conflicts': conflicts}
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
cases = {
1: [('only ours changed', [['a', 'b', 'c', 'd', 'e'], ['a', 'B', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e']], {'merged': ['a', 'B', 'c', 'd', 'e'], 'conflicts': 0}), ('only theirs deleted a line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'd', 'e']], {'merged': ['a', 'b', 'd', 'e'], 'conflicts': 0}), ('both made the same change', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'C1', 'd', 'e'], ['a', 'b', 'C1', 'd', 'e']], {'merged': ['a', 'b', 'C1', 'd', 'e'], 'conflicts': 0}), ('both deleted the same line', [['a', 'b', 'c', 'd', 'e'], ['a', 'c', 'd', 'e'], ['a', 'c', 'd', 'e']], {'merged': ['a', 'c', 'd', 'e'], 'conflicts': 0}), ('conflicting edits', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'X', 'd', 'e'], ['a', 'b', 'Y', 'd', 'e']], {'merged': ['a', 'b', '<<<<<<< ours', 'X', '||||||| base', 'c', '=======', 'Y', '>>>>>>> theirs', 'd', 'e'], 'conflicts': 1}), ('changes after the last stable line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e', 'o0'], ['a', 'b', 'c', 'd', 'e', 'T']], {'merged': ['a', 'b', 'c', 'd', 'e', '<<<<<<< ours', 'o0', '||||||| base', '=======', 'T', '>>>>>>> theirs'], 'conflicts': 1}), ('appended by one side only', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e', 't0']], {'merged': ['a', 'b', 'c', 'd', 'e', 't0'], 'conflicts': 0}), ('changes on both sides in different places', [['a', 'b', 'c', 'd', 'e'], ['A', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'D', 'e']], {'merged': ['A', 'b', 'c', 'D', 'e'], 'conflicts': 0}), ('theirs changes the last base line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'E']], {'merged': ['a', 'b', 'c', 'd', 'E'], 'conflicts': 0})],
2: [('only ours changed', [['a', 'b', 'c', 'd', 'e'], ['a', 'B', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e']], {'merged': ['a', 'B', 'c', 'd', 'e'], 'conflicts': 0}), ('only theirs deleted a line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'd', 'e']], {'merged': ['a', 'b', 'd', 'e'], 'conflicts': 0}), ('both made the same change', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'C2', 'd', 'e'], ['a', 'b', 'C2', 'd', 'e']], {'merged': ['a', 'b', 'C2', 'd', 'e'], 'conflicts': 0}), ('both deleted the same line', [['a', 'b', 'c', 'd', 'e'], ['a', 'c', 'd', 'e'], ['a', 'c', 'd', 'e']], {'merged': ['a', 'c', 'd', 'e'], 'conflicts': 0}), ('conflicting edits', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'X', 'd', 'e'], ['a', 'b', 'Y', 'd', 'e']], {'merged': ['a', 'b', '<<<<<<< ours', 'X', '||||||| base', 'c', '=======', 'Y', '>>>>>>> theirs', 'd', 'e'], 'conflicts': 1}), ('changes after the last stable line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e', 'o0', 'o1'], ['a', 'b', 'c', 'd', 'e', 'T']], {'merged': ['a', 'b', 'c', 'd', 'e', '<<<<<<< ours', 'o0', 'o1', '||||||| base', '=======', 'T', '>>>>>>> theirs'], 'conflicts': 1}), ('appended by one side only', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e', 't0', 't1']], {'merged': ['a', 'b', 'c', 'd', 'e', 't0', 't1'], 'conflicts': 0}), ('changes on both sides in different places', [['a', 'b', 'c', 'd', 'e'], ['A', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'D', 'e']], {'merged': ['A', 'b', 'c', 'D', 'e'], 'conflicts': 0}), ('theirs changes the last base line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'E']], {'merged': ['a', 'b', 'c', 'd', 'E'], 'conflicts': 0})],
3: [('only ours changed', [['a', 'b', 'c', 'd', 'e'], ['a', 'B', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e']], {'merged': ['a', 'B', 'c', 'd', 'e'], 'conflicts': 0}), ('only theirs deleted a line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'd', 'e']], {'merged': ['a', 'b', 'd', 'e'], 'conflicts': 0}), ('both made the same change', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'C3', 'd', 'e'], ['a', 'b', 'C3', 'd', 'e']], {'merged': ['a', 'b', 'C3', 'd', 'e'], 'conflicts': 0}), ('both deleted the same line', [['a', 'b', 'c', 'd', 'e'], ['a', 'c', 'd', 'e'], ['a', 'c', 'd', 'e']], {'merged': ['a', 'c', 'd', 'e'], 'conflicts': 0}), ('conflicting edits', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'X', 'd', 'e'], ['a', 'b', 'Y', 'd', 'e']], {'merged': ['a', 'b', '<<<<<<< ours', 'X', '||||||| base', 'c', '=======', 'Y', '>>>>>>> theirs', 'd', 'e'], 'conflicts': 1}), ('changes after the last stable line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e', 'o0', 'o1', 'o2'], ['a', 'b', 'c', 'd', 'e', 'T']], {'merged': ['a', 'b', 'c', 'd', 'e', '<<<<<<< ours', 'o0', 'o1', 'o2', '||||||| base', '=======', 'T', '>>>>>>> theirs'], 'conflicts': 1}), ('appended by one side only', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e', 't0', 't1', 't2']], {'merged': ['a', 'b', 'c', 'd', 'e', 't0', 't1', 't2'], 'conflicts': 0}), ('changes on both sides in different places', [['a', 'b', 'c', 'd', 'e'], ['A', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'D', 'e']], {'merged': ['A', 'b', 'c', 'D', 'e'], 'conflicts': 0}), ('theirs changes the last base line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'E']], {'merged': ['a', 'b', 'c', 'd', 'E'], 'conflicts': 0})],
4: [('only ours changed', [['a', 'b', 'c', 'd', 'e'], ['a', 'B', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e']], {'merged': ['a', 'B', 'c', 'd', 'e'], 'conflicts': 0}), ('only theirs deleted a line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'd', 'e']], {'merged': ['a', 'b', 'd', 'e'], 'conflicts': 0}), ('both made the same change', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'C4', 'd', 'e'], ['a', 'b', 'C4', 'd', 'e']], {'merged': ['a', 'b', 'C4', 'd', 'e'], 'conflicts': 0}), ('both deleted the same line', [['a', 'b', 'c', 'd', 'e'], ['a', 'c', 'd', 'e'], ['a', 'c', 'd', 'e']], {'merged': ['a', 'c', 'd', 'e'], 'conflicts': 0}), ('conflicting edits', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'X', 'd', 'e'], ['a', 'b', 'Y', 'd', 'e']], {'merged': ['a', 'b', '<<<<<<< ours', 'X', '||||||| base', 'c', '=======', 'Y', '>>>>>>> theirs', 'd', 'e'], 'conflicts': 1}), ('changes after the last stable line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e', 'o0', 'o1', 'o2', 'o3'], ['a', 'b', 'c', 'd', 'e', 'T']], {'merged': ['a', 'b', 'c', 'd', 'e', '<<<<<<< ours', 'o0', 'o1', 'o2', 'o3', '||||||| base', '=======', 'T', '>>>>>>> theirs'], 'conflicts': 1}), ('appended by one side only', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e', 't0', 't1', 't2', 't3']], {'merged': ['a', 'b', 'c', 'd', 'e', 't0', 't1', 't2', 't3'], 'conflicts': 0}), ('changes on both sides in different places', [['a', 'b', 'c', 'd', 'e'], ['A', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'D', 'e']], {'merged': ['A', 'b', 'c', 'D', 'e'], 'conflicts': 0}), ('theirs changes the last base line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'E']], {'merged': ['a', 'b', 'c', 'd', 'E'], 'conflicts': 0})],
5: [('only ours changed', [['a', 'b', 'c', 'd', 'e'], ['a', 'B', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e']], {'merged': ['a', 'B', 'c', 'd', 'e'], 'conflicts': 0}), ('only theirs deleted a line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'd', 'e']], {'merged': ['a', 'b', 'd', 'e'], 'conflicts': 0}), ('both made the same change', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'C5', 'd', 'e'], ['a', 'b', 'C5', 'd', 'e']], {'merged': ['a', 'b', 'C5', 'd', 'e'], 'conflicts': 0}), ('both deleted the same line', [['a', 'b', 'c', 'd', 'e'], ['a', 'c', 'd', 'e'], ['a', 'c', 'd', 'e']], {'merged': ['a', 'c', 'd', 'e'], 'conflicts': 0}), ('conflicting edits', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'X', 'd', 'e'], ['a', 'b', 'Y', 'd', 'e']], {'merged': ['a', 'b', '<<<<<<< ours', 'X', '||||||| base', 'c', '=======', 'Y', '>>>>>>> theirs', 'd', 'e'], 'conflicts': 1}), ('changes after the last stable line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e', 'o0', 'o1', 'o2', 'o3', 'o4'], ['a', 'b', 'c', 'd', 'e', 'T']], {'merged': ['a', 'b', 'c', 'd', 'e', '<<<<<<< ours', 'o0', 'o1', 'o2', 'o3', 'o4', '||||||| base', '=======', 'T', '>>>>>>> theirs'], 'conflicts': 1}), ('appended by one side only', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e', 't0', 't1', 't2', 't3', 't4']], {'merged': ['a', 'b', 'c', 'd', 'e', 't0', 't1', 't2', 't3', 't4'], 'conflicts': 0}), ('changes on both sides in different places', [['a', 'b', 'c', 'd', 'e'], ['A', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'D', 'e']], {'merged': ['A', 'b', 'c', 'D', 'e'], 'conflicts': 0}), ('theirs changes the last base line', [['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'e'], ['a', 'b', 'c', 'd', 'E']], {'merged': ['a', 'b', 'c', 'd', 'E'], 'conflicts': 0})],
}[N]
for label, args, expected in cases:
check(label, solve(*args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
| Boundary fixture | Actual | Expected | Outcome |
|---|---|---|---|
| only ours changed | {'conflicts': 0, 'merged': ['a', 'B', 'c', 'd', 'e']} | {'conflicts': 0, 'merged': ['a', 'B', 'c', 'd', 'e']} | Passed |
| only theirs deleted a line | {'conflicts': 0, 'merged': ['a', 'b', 'd', 'e']} | {'conflicts': 0, 'merged': ['a', 'b', 'd', 'e']} | Passed |
| both made the same change | {'conflicts': 0, 'merged': ['a', 'b', 'C1', 'd', 'e']} | {'conflicts': 0, 'merged': ['a', 'b', 'C1', 'd', 'e']} | Passed |
| both deleted the same line | {'conflicts': 0, 'merged': ['a', 'c', 'd', 'e']} | {'conflicts': 0, 'merged': ['a', 'c', 'd', 'e']} | Passed |
| conflicting edits | {'conflicts': 1, 'merged': ['a', 'b', '<<<<<<< ours', 'X', '||||||| base', 'c', '=======', 'Y', '>>>>>>> theirs', 'd', 'e']} | {'conflicts': 1, 'merged': ['a', 'b', '<<<<<<< ours', 'X', '||||||| base', 'c', '=======', 'Y', '>>>>>>> theirs', 'd', 'e']} | Passed |
| changes after the last stable line | {'conflicts': 1, 'merged': ['a', 'b', 'c', 'd', 'e', '<<<<<<< ours', 'o0', '||||||| base', '=======', 'T', '>>>>>>> theirs']} | {'conflicts': 1, 'merged': ['a', 'b', 'c', 'd', 'e', '<<<<<<< ours', 'o0', '||||||| base', '=======', 'T', '>>>>>>> theirs']} | Passed |
| appended by one side only | {'conflicts': 0, 'merged': ['a', 'b', 'c', 'd', 'e', 't0']} | {'conflicts': 0, 'merged': ['a', 'b', 'c', 'd', 'e', 't0']} | Passed |
| changes on both sides in different places | {'conflicts': 0, 'merged': ['A', 'b', 'c', 'D', 'e']} | {'conflicts': 0, 'merged': ['A', 'b', 'c', 'D', 'e']} | Passed |
| theirs changes the last base line | {'conflicts': 0, 'merged': ['a', 'b', 'c', 'd', 'E']} | {'conflicts': 0, 'merged': ['a', 'b', 'c', 'd', 'E']} | Passed |
SHA-256 / 49406ae7d09c60d0a236e21e0e5f54274ecae938b4d0f70dc9ac08aad069a425
Verification & scope
A deterministic, bounded teaching model of one diff, patch or merge rule with stipulated conventions; it is not a production diff or version-control implementation and makes no claim of conformance to any specific tool. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.
Observations recorded using Python 3.12.14 at 2026-09-29T14:49:06.695796+00:00.
Case digest / 2ce86df4e7268a7de8a93a625e57eaf067a96844c713d36139785ec5fb55efd5