[BUG] Crash on conversation resume: "null is not an object (evaluating 'q.split')" in diff renderer

Found 1 possible duplicate issue:

1. https://github.com/anthropics/claude-code/issues/37454

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Additional root cause analysis

I hit the same crash on v2.1.83 (macOS arm64, Bedrock) resuming a 26,668-line conversation originally created on v2.1.71.

Root cause

The pl7 function (Edit tool success renderer in cli.js:3163) calls originalFile.split('\n') without a null guard. The originalFile value is resolved from file-history-snapshot entries in the conversation JSONL, keyed by the assistant message's UUID. When no snapshot exists for a given UUID, originalFile is null.

In my case, 297 out of 328 Edit tool_use entries had no corresponding file-history-snapshot. The conversation was forked from another session (has a forkedFrom field in line 0) — the fork likely didn't carry over snapshots from the parent.

Minimal fix

// In pl7:
firstLine: (originalFile ?? "").split('\n')[0] ?? null,
fileContent: originalFile ?? "",

Workaround (patching the JSONL)

I was able to resume by injecting missing file-history-snapshot entries into the JSONL. For each assistant message UUID that contained an Edit tool_use but had no snapshot, I added:

{"type":"file-history-snapshot","messageId":"<uuid>","snapshot":{"<file_path>":"<current_file_content>"},"isSnapshotUpdate":false}

This prevents the null crash. Historical diffs won't render accurately (uses current file content instead of the original), but the conversation loads and is fully usable.

Script to automate: read all lines, find Edit tool_use UUIDs missing from snapshot messageIds, inject entries with current disk content, write back. Backup first.

Working workaround: binary patch (macOS arm64, v2.1.83)

The file-history-snapshot JSONL patching I described above does not work — the renderer resolves originalFile through a different mechanism than snapshot messageId lookup.

What does work is patching the binary directly. The crash is in pl7 where q.split() is called on null originalFile. The fix replaces q.split(...)??null with (q??"").split(...) — exact same byte length, safe in-place patch:

import shutil

binary_path = '/opt/homebrew/Caskroom/claude-code/2.1.83/claude'
backup_path = binary_path + '.bak'
shutil.copy2(binary_path, backup_path)

with open(binary_path, 'rb') as f:
    data = f.read()

original    = b'firstLine:q.split(`\n`)[0]??null,fileContent:q'
replacement = b'firstLine:(q??"").split(`\n`)[0],fileContent:q'

assert len(original) == len(replacement) == 45  # same byte length

patched = data.replace(original, replacement)
# Should replace 2 occurrences (positions ~78M and ~183M in the binary)

with open(binary_path, 'wb') as f:
    f.write(patched)

Then re-sign for macOS:

codesign --remove-signature /opt/homebrew/Caskroom/claude-code/2.1.83/claude
codesign -s - /opt/homebrew/Caskroom/claude-code/2.1.83/claude
xattr -cr /opt/homebrew/Caskroom/claude-code/2.1.83/claude

macOS will show a Gatekeeper warning on first run — go to System Settings → Privacy & Security → Allow Anyway.

Confirmed working: resumes a 26,668-line conversation with 44 subagents and 328 Edit tool calls that previously crashed instantly.

Note: brew upgrade claude-code will overwrite this patch. Re-apply after updates until an official fix ships.

Update: v2.1.84 has a SECOND crash in the same function

After upgrading to v2.1.84, the originalFile.split() crash is still present (not fixed upstream). Additionally, there's a second null-safety issue: filePath can also be undefined, causing undefined.startsWith().

The actual function in the binary (v2.1.84) is called fs6, not pl7 (source-mapped name):

// Actual binary (v2.1.84), deobfuscated:
function fs6({filePath:H, structuredPatch:_, originalFile:T}, q, {style:A, verbose:$}) {
    let R = H.startsWith(sK());  // CRASH 1: H can be undefined
    return VO.createElement(Kg_, {
        filePath: H,
        structuredPatch: _,
        firstLine: T.split('\n')[0] ?? null,  // CRASH 2: T can be null
        fileContent: T,
        style: A,
        verbose: $,
        previewHint: R ? "/plan to preview" : void 0
    });
}

Updated binary patch for v2.1.84

Two same-length replacements (both found at 2 positions each):

import shutil

binary_path = '/opt/homebrew/Caskroom/claude-code/2.1.84/claude'
shutil.copy2(binary_path, binary_path + '.bak')

with open(binary_path, 'rb') as f:
    data = f.read()

# Fix 1: filePath (H) can be undefined
# R=false means plan preview hint won't show (harmless cosmetic)
data = data.replace(
    b'let R=H.startsWith(sK());',
    b'let R=!1;                '   # 25 bytes, padded with spaces
)

# Fix 2: originalFile (T) can be null (same as v2.1.83 issue)
data = data.replace(
    b'firstLine:T.split(`\n`)[0]??null,fileContent:T',
    b'firstLine:(T??"").split(`\n`)[0],fileContent:T'   # 45 bytes
)

with open(binary_path, 'wb') as f:
    f.write(data)

Then re-sign:

codesign --remove-signature /opt/homebrew/Caskroom/claude-code/2.1.84/claude
codesign -s - /opt/homebrew/Caskroom/claude-code/2.1.84/claude
xattr -cr /opt/homebrew/Caskroom/claude-code/2.1.84/claude

Allow in System Settings → Privacy & Security on first run.

Confirmed working on a 26K-line conversation with 44 subagents.

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