FA-75446 / Text diff and three-way merge / Open access
diff3 chunk merge: identical edits on both sides are reported as a conflict · case 01
Both branches made the same change and the merge still stops with a conflict.
ROOT CAUSE
There is no branch for regions where ours and theirs changed identically.
VERIFIED REPAIR
Treat identical changes on both sides as a clean merge taking that change.
Unsuccessful approach: Requiring the identical change to be non-empty still conflicts when both sides deleted the same lines.
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] + [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)
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': 1, 'merged': ['a', 'b', '<<<<<<< ours', 'C1', '||||||| base', 'c', '=======', 'C1', '>>>>>>> theirs', 'd', 'e']} | {'conflicts': 0, 'merged': ['a', 'b', 'C1', 'd', 'e']} | Failed |
| both deleted the same line | {'conflicts': 1, 'merged': ['a', '<<<<<<< ours', '||||||| base', 'b', '=======', '>>>>>>> theirs', 'c', 'd', 'e']} | {'conflicts': 0, 'merged': ['a', 'c', 'd', 'e']} | Failed |
| 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 / 8b841cc3dd17ffc4ffd59bcd9c03c5aad5b99fa7d5a983e58292a35947abe226
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:
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 and O:
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': 1, 'merged': ['a', '<<<<<<< ours', '||||||| base', 'b', '=======', '>>>>>>> theirs', 'c', 'd', 'e']} | {'conflicts': 0, 'merged': ['a', 'c', 'd', 'e']} | Failed |
| 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 / 038906fe2febf0742a525d7f6652e9386d6c9d84c84d603c9b64c9b7eea693c4
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 2026-09-29T14:49:06.649679+00:00.
Case digest / edd19d79e0c52bae18f7f7d149535caf018f845e4922a49ba849410f420beadb