Bug #17: multi_edit Misleading Success Counter

Status: RESOLVED in v3.16.0 Category: Correctness / Verification Severity: Medium-High (misleading output forces wasteful re-reads to verify) Resolution Date: 2026-03-02

Problem

multi_edit reported ambiguous results. In real-world usage:

OK: 1/2 edits, 193 lines [backup:20260302-165154-27ead86d9eb8ef82]

The message indicated that only 1 of 2 edits was applied — but reading the file confirmed both changes were present. The only way to verify was a manual read_file_range call on the edited zone, wasting tokens.

Root Cause

When Edit 1’s replacement subsumes Edit 2’s intended change (overlapping edits), Edit 2’s oldText no longer exists in currentContent after Edit 1 is applied. The edit loop marked it as “failed” even though the file was already in the correct state.

Example:

1. Edit 1: Replace entire function body (includes the line Edit 2 targets)
2. Edit 2: Replace just one line within that function → oldText gone → “failed”
3. Result: “1/2 edits” but file is correct

Additional Issues

Comparing EditFile() vs MultiEdit(), MultiEdit was missing:

Feature	EditFile	MultiEdit (before fix)
Risk assessment	CalculateChangeImpact()	Missing
CRITICAL blocking	ShouldBlockOperation()	Missing
Risk warning	FormatRiskNotice()	Missing
Context validation	validateEditContext()	Missing
Pre/Post hooks	HookPreEdit / HookPostEdit	Missing
Per-edit detail	N/A (single edit)	Missing

Why It Matters

• Misleading output: “1/2 edits” implies failure when the file is correct
• Wasted tokens: Forced read_file_range verification calls after every multi_edit
• No risk protection: CRITICAL risk rewrites via multi_edit bypassed all safety checks
• No hooks: Custom validation logic could not intervene in batch edits

Solution

1. “Already Present” Detection

When performIntelligentEdit fails for an edit, check:

• Is newText already present in currentContent?
• Is oldText absent from currentContent?

If both true → the edit was subsumed by a prior edit in the batch. Count as already_present (not failed).

2. Per-Edit Status Detail

New EditDetail struct captures the outcome of each individual edit:

type EditDetailStatus string // "applied", "already_present", "failed"

type EditDetail struct {
    Index           int
    Status          EditDetailStatus
    OldTextSnippet  string
    NewTextSnippet  string
    MatchConfidence string
    Error           string
}

3. Full Parity with EditFile

Feature	Implementation
Context validation	Validates all edits against original content; only hard-blocks if NO edit passes
Risk assessment	Simulates all edits to compute aggregate impact on final vs original content
CRITICAL blocking	ShouldBlockOperation(force) — only >=90% blocks without force: true
Risk warning	FormatRiskNotice() for MEDIUM/HIGH appended to response
Pre/Post hooks	HookPreEdit before loop, HookPostEdit after write
Skip unnecessary write	If all edits are already_present, no file I/O occurs

4. Improved Response Format

Compact mode:

OK: 2 edits (1 applied, 1 already present), 193 lines [backup:xxx]

Verbose mode:

Multi-edit completed on /path/to/file
Total edits: 2
Applied: 1
Already present: 1
Lines affected: 193
Confidence: high

Edit details:
  edit 1: applied (confidence: high)
  edit 2: already present (subsumed by prior edit)

Files Changed

File	Change
core/edit_operations.go	EditDetailStatus, EditDetail types; MultiEditResult extended with SkippedEdits + EditDetails; MultiEdit() rewritten with context validation, risk assessment, hooks, already_present detection; calculateMultiEditImpact() + truncateText() helpers
main.go	multi_edit handler response formatting for compact and verbose modes
tests/bug17_test.go	9 regression tests
tests/bug16_test.go	Test content enlarged to avoid CRITICAL threshold on small files

Testing

• 9 new regression tests in tests/bug17_test.go:
  • TestBug17_OverlappingEditsNotMisreported — Edit 1 subsumes Edit 2 → SkippedEdits=1, FailedEdits=0
  • TestBug17_AllEditsApplied — 2 independent edits → SuccessfulEdits=2
  • TestBug17_GenuineFailureStillReported — missing oldText → FailedEdits=1
  • TestBug17_RiskAssessmentCriticalBlocks — ~100% rewrite without force → OPERATION BLOCKED
  • TestBug17_RiskAssessmentCriticalForceProceeds — force=true bypasses CRITICAL
  • TestBug17_EditDetailsPopulated — 3 mixed edits → EditDetails with 3 entries
  • TestBug17_BackwardCompatibility — original fields (TotalEdits, SuccessfulEdits, etc.) still work
  • TestBug17_AllAlreadyPresent — all edits already present → no write, SkippedEdits=2
  • TestBug17_MixedOverlapAndIndependent — batch with overlap + independent edits
• Build: go build passes
• Full suite: go test ./... all pass