Panic when rendering large "count by" result as SUP

[philrz]

$ super -s -dynamic -c "count() by commit" repro.bsup.gz > /dev/null
panic: bad uvarint: 0

goroutine 1 [running]:
github.com/brimdata/super/scode.(*Iter).Next(0xda86ad0?)
	/Users/phil/work/super/scode/iter.go:26 +0x219
github.com/brimdata/super.Value.ContainerLength({{0xda86ad0?, 0xc0005c43a8?}, 0xc001ceafb0?, 0xc000fa6fc0?})
	/Users/phil/work/super/value.go:245 +0xd8
github.com/brimdata/super/sup.(*Formatter).formatVector(0xc00042c6c0, 0x0, {0xd5ffb74?, 0x8?}, {0xd5fa198, 0x1}, {0xda86b20, 0xc000000d50}, {{0xda86ad0, 0xc0005c43a8}, ...}, ...)
	/Users/phil/work/super/sup/formatter.go:417 +0x1a5
github.com/brimdata/super/sup.(*Formatter).formatValue(0xc00042c6c0, 0x0, {0xda86ad0, 0xc0005c43a8}, {0xc001ceafb0, 0x6c, 0xcb}, 0x0, 0x0, 0x1)
	/Users/phil/work/super/sup/formatter.go:158 +0x609
github.com/brimdata/super/sup.(*Formatter).formatRecord(0xc00042c6c0, 0xda869e0?, 0xec6ba20?, {0xc001ceaf67?, 0x18?, 0xc000fa7270?}, 0x0, 0x0)
	/Users/phil/work/super/sup/formatter.go:408 +0x2d3
github.com/brimdata/super/sup.(*Formatter).formatValue(0xc00042c6c0, 0x0, {0xda86b20, 0xc000000db0}, {0xc001ceaf67, 0xc8, 0x114}, 0x0, 0x0, 0x1)
	/Users/phil/work/super/sup/formatter.go:156 +0x2a5
github.com/brimdata/super/sup.(*Formatter).formatRecord(0xc00042c6c0, 0xda869e0?, 0xec6ba20?, {0xc001ceaf35?, 0x4?, 0xc000fa7438?}, 0x0, 0x0)
	/Users/phil/work/super/sup/formatter.go:408 +0x2d3
github.com/brimdata/super/sup.(*Formatter).formatValue(0xc00042c6c0, 0x0, {0xda86b20, 0xc0001bc7e0}, {0xc001ceaf35, 0x108, 0x146}, 0x0, 0x0, 0x1)
	/Users/phil/work/super/sup/formatter.go:156 +0x2a5
github.com/brimdata/super/sup.(*Formatter).formatRecord(0xc00042c6c0, 0x0?, 0xc0001bc8a0?, {0xc001ceaf02?, 0x177?, 0x179?}, 0x0, 0x0)
	/Users/phil/work/super/sup/formatter.go:408 +0x2d3
github.com/brimdata/super/sup.(*Formatter).formatValue(0xc00042c6c0, 0x0, {0xda86b20, 0xc0001bc8a0}, {0xc001ceaf02, 0x177, 0x179}, 0x0, 0x0, 0x1)
	/Users/phil/work/super/sup/formatter.go:156 +0x2a5
github.com/brimdata/super/sup.(*Formatter).formatRecord(0xc00042c6c0, 0x0?, 0xc01d108ae0?, {0xc001ceaf00?, 0x17b?, 0x17b?}, 0x0, 0x0)
	/Users/phil/work/super/sup/formatter.go:408 +0x2d3
github.com/brimdata/super/sup.(*Formatter).formatValue(0xc00042c6c0, 0x0, {0xda86b20, 0xc01d108ae0}, {0xc001ceaf00, 0x17b, 0x17b}, 0x0, 0x0, 0x0)
	/Users/phil/work/super/sup/formatter.go:156 +0x2a5
github.com/brimdata/super/sup.(*Formatter).formatValueAndDecorate(0xc00042c6c0, {0xda86b20, 0xc01d108ae0?}, {0xc001ceaf00, 0x17b, 0x17b})
	/Users/phil/work/super/sup/formatter.go:134 +0x197
github.com/brimdata/super/sup.(*Formatter).Format(0xc00042c6c0, {{0xda86b20?, 0xc01d108ae0?}, 0xc001ceaf00?, 0xc000fa7c10?})
	/Users/phil/work/super/sup/formatter.go:99 +0x92
github.com/brimdata/super/sup.(*Formatter).FormatValue(...)
	/Users/phil/work/super/sup/formatter.go:76
github.com/brimdata/super/sio/supio.(*Writer).Write(0xc00050ef30, {{0xda86b20?, 0xc01d108ae0?}, 0xc001ceaf00?, 0xc000fa79d0?})
	/Users/phil/work/super/sio/supio/writer.go:34 +0x8c
github.com/brimdata/super/sbuf.WriteBatch({0x570da3a0, 0xc00050ef30}, {0xda91ba0?, 0xc00e9589a0?})
	/Users/phil/work/super/sbuf/batch.go:39 +0x83
github.com/brimdata/super/sbuf.CopyMux(0xc000fa7d10, {0xda7e1a0, 0xc0003ab470})
	/Users/phil/work/super/sbuf/mux.go:49 +0x106
github.com/brimdata/super/cmd/super/root.(*Command).Run(0xc0003866c8, {0xc00003e2f0, 0x1, 0x1})
	/Users/phil/work/super/cmd/super/root/command.go:108 +0x9e7
github.com/brimdata/super/pkg/charm.path.run({0xc00007ea70, 0x1, 0x1}, {0xc00003e2f0, 0x1, 0x0?})
	/Users/phil/work/super/pkg/charm/path.go:11 +0x7b
github.com/brimdata/super/pkg/charm.(*Spec).Exec(0xec302c0, {0xc00003e2b0, 0x5, 0x5})
	/Users/phil/work/super/pkg/charm/charm.go:74 +0x1fa
main.main()
	/Users/phil/work/super/cmd/super/main.go:39 +0x5b

Details

Repro is with super version 0b7c3b9.

It seems I need a fairly large amount of input data to trigger the problem and it's too much to attach in a GitHub Issue, but it can be downloaded from https://super-issues.s3.us-east-2.amazonaws.com/super-6614/repro.bsup.gz.

Sometimes on repeated repros, instead of the bad uvarint panic shown above, I can get a slice bounds out instead.

$ super -version
Version: v0.1.0-14-g0b7c3b979

$ super -s -dynamic -c "count() by commit" repro.bsup.gz > /dev/null
panic: runtime error: slice bounds out of range [:50] with capacity 24

goroutine 1 [running]:
github.com/brimdata/super/scode.(*Iter).Next(0x746cad0?)
	/Users/phil/work/super/scode/iter.go:33 +0x1b9
github.com/brimdata/super.Value.ContainerLength({{0x746cad0?, 0xc000597638?}, 0xc002d2165a?, 0xc000f31190?})
	/Users/phil/work/super/value.go:245 +0xd8
github.com/brimdata/super/sup.(*Formatter).formatVector(0xc000166870, 0x0, {0x6fe5b74?, 0x8651a20?}, {0x6fe0198, 0x1}, {0x746cb20, 0xc0003ab740}, {{0x746cad0, 0xc000597638}, ...}, ...)
	/Users/phil/work/super/sup/formatter.go:417 +0x1a5
github.com/brimdata/super/sup.(*Formatter).formatValue(0xc000166870, 0x0, {0x746cad0, 0xc000597638}, {0xc002d2165a, 0x18, 0x9d}, 0x0, 0x1, 0x1)
	/Users/phil/work/super/sup/formatter.go:158 +0x609
github.com/brimdata/super/sup.(*Formatter).formatRecord(0xc000166870, 0x746c9e0?, 0x8651a20?, {0xc002d2163f?, 0xd?, 0xc000f31438?}, 0x0, 0x1)
	/Users/phil/work/super/sup/formatter.go:408 +0x2d3
github.com/brimdata/super/sup.(*Formatter).formatValue(0xc000166870, 0x0, {0x746cb20, 0xc0003ab7a0}, {0xc002d2163f, 0x7a, 0xb8}, 0x0, 0x1, 0x1)
	/Users/phil/work/super/sup/formatter.go:156 +0x2a5
github.com/brimdata/super/sup.(*Formatter).formatRecord(0xc000166870, 0x0?, 0xc0003ab800?, {0xc002d21602?, 0xf3?, 0xf5?}, 0x0, 0x1)
	/Users/phil/work/super/sup/formatter.go:408 +0x2d3
github.com/brimdata/super/sup.(*Formatter).formatValue(0xc000166870, 0x0, {0x746cb20, 0xc0003ab800}, {0xc002d21602, 0xf3, 0xf5}, 0x0, 0x1, 0x1)
	/Users/phil/work/super/sup/formatter.go:156 +0x2a5
github.com/brimdata/super/sup.(*Formatter).formatRecord(0xc000166870, 0x0?, 0xc00ceaf7a0?, {0xc002d21600?, 0xf7?, 0xf7?}, 0x0, 0x1)
	/Users/phil/work/super/sup/formatter.go:408 +0x2d3
github.com/brimdata/super/sup.(*Formatter).formatValue(0xc000166870, 0x0, {0x746cb20, 0xc00ceaf7a0}, {0xc002d21600, 0xf7, 0xf7}, 0x0, 0x1, 0x0)
	/Users/phil/work/super/sup/formatter.go:156 +0x2a5
github.com/brimdata/super/sup.(*Formatter).formatValueAndDecorate(0xc000166870, {0x746cb20, 0xc00ceaf7a0?}, {0xc002d21600, 0xf7, 0xf7})
	/Users/phil/work/super/sup/formatter.go:134 +0x197
github.com/brimdata/super/sup.(*Formatter).Format(0xc000166870, {{0x746cb20?, 0xc00ceaf7a0?}, 0xc002d21600?, 0xc000f31c10?})
	/Users/phil/work/super/sup/formatter.go:99 +0x92
github.com/brimdata/super/sup.(*Formatter).FormatValue(...)
	/Users/phil/work/super/sup/formatter.go:76
github.com/brimdata/super/sio/supio.(*Writer).Write(0xc000369038, {{0x746cb20?, 0xc00ceaf7a0?}, 0xc002d21600?, 0xc000f319d0?})
	/Users/phil/work/super/sio/supio/writer.go:34 +0x8c
github.com/brimdata/super/sbuf.WriteBatch({0x50797ea8, 0xc000369038}, {0x7477ba0?, 0xc003f5ec20?})
	/Users/phil/work/super/sbuf/batch.go:39 +0x83
github.com/brimdata/super/sbuf.CopyMux(0xc000f31d10, {0x74641a0, 0xc0003e7da0})
	/Users/phil/work/super/sbuf/mux.go:49 +0x106
github.com/brimdata/super/cmd/super/root.(*Command).Run(0xc000422488, {0xc00003e2f0, 0x1, 0x1})
	/Users/phil/work/super/cmd/super/root/command.go:108 +0x9e7
github.com/brimdata/super/pkg/charm.path.run({0xc00042a1a8, 0x1, 0x1}, {0xc00003e2f0, 0x1, 0x0?})
	/Users/phil/work/super/pkg/charm/path.go:11 +0x7b
github.com/brimdata/super/pkg/charm.(*Spec).Exec(0x86162c0, {0xc00003e2b0, 0x5, 0x5})
	/Users/phil/work/super/pkg/charm/charm.go:74 +0x1fa
main.main()
	/Users/phil/work/super/cmd/super/main.go:39 +0x5b