Version

Slackdump 3.1.11 built on: 2025-12-14T10:51:00Z

Description

slackdump format text panics with "slice bounds out of range [1:0]" when processing an archive that contains a thread where:

• The thread parent message is within the archived time range
• All thread replies are outside the archived time range

This results in getThread() returning an empty slice, and the subsequent mm[1:] panics.

Steps to Reproduce

1. Archive a workspace with a time range that captures a thread parent but not its replies:

   slackdump archive -files=false -time-from=2026-01-19T08:00:00 -time-to=2026-01-20T07:59:59 CHANNEL_ID

2. Run format text on the archive:

   slackdump format text ./slackdump_YYYYMMDD_HHMMSS

3. Panic occurs if any channel has a thread where parent exists but replies don't

Stack Trace

panic: runtime error: slice bounds out of range [1:0]

goroutine 1 [running]:
github.com/rusq/slackdump/v3/cmd/slackdump/internal/format.getThread({0x10366adb8, 0x14000690930}, {0x103673410, 0x140006c83c0}, {0x14000a18210, 0x9}, {0x14000d7acc0, 0x11})
        github.com/rusq/slackdump/v3/cmd/slackdump/internal/format/source.go:131 +0x250
github.com/rusq/slackdump/v3/cmd/slackdump/internal/format.getChannel-range1(...)
        github.com/rusq/slackdump/v3/cmd/slackdump/internal/format/source.go:102 +0x284
...

Root Cause

In cmd/slackdump/internal/format/source.go, the getThread function at line 131:

func getThread(ctx context.Context, src source.Sourcer, chanID string, ts string) ([]types.Message, error) {
    itt, err := src.AllThreadMessages(ctx, chanID, ts)
    if err != nil {
        return nil, err
    }
    var mm []types.Message
    for threadMsg, err := range itt {
        if err != nil {
            return nil, err
        }
        mm = append(mm, types.Message{Message: threadMsg})
    }
    return mm[1:], nil  // <-- panics if mm is empty or has only 1 element
}

The mm[1:] slice operation assumes there's at least one message to skip (the thread parent), but when the thread replies are outside the time range, mm can be empty.

Suggested Fix

Add a bounds check before slicing:

if len(mm) <= 1 {
    return nil, nil // No thread replies to return
}
return mm[1:], nil

Workaround

Currently, the only workaround is to avoid archiving channels that have threads where the parent is in-range but replies are out-of-range, which is difficult to predict.