GumpacG opened a new pull request, #3522:
URL: https://github.com/apache/tinkerpop/pull/3522
# gremlin-go bug fixes
Two gremlin-go bugs introduced in 4.0.0-beta.2. Both made gremlin-go the only
GLV producing incorrect results; the fixes align it with gremlin-java,
gremlin-python, gremlin-dotnet, and gremlin-javascript.
## 1. Negative BigInteger / BigDecimal decoded incorrectly
Problem: `readBigInt` reconstructed negative two's-complement values with a
bit
width one byte too wide (`(len(b)+1)*8` instead of `len(b)*8`), so it
subtracted a
power of two that was 256x too large. Positive values were unaffected.
Negative
`BigDecimal` values were affected too, because their unscaled value decodes
through
the same path. Go was the only GLV with this bug because it hand-rolls the
conversion (`math/big` has no signed-bytes constructor), while the other GLVs
delegate to a correct standard-library primitive.
Use case: a ledger service stores account balances as arbitrary-precision
integers
so they never overflow. Account `acct-1` is overdrawn by 500, stored as the
`BigInteger` `-500`.
Before:
```go
r, _ := g.V("acct-1").Values("balance").Next()
balance := r.GetInterface() // *big.Int
// want: -500
// got: -16712180 (silently wrong, no error returned)
```
The application reads a balance of -16,712,180 for an account that is only
500
overdrawn. The error is silent, so it can flow into downstream calculations,
alerts, or stored data before anyone notices.
After:
```go
r, _ := g.V("acct-1").Values("balance").Next()
balance := r.GetInterface() // *big.Int
// -500, matching the server and every other GLV
```
## 2. P.outside() generated invalid gremlin-lang
Problem: `translatePValue` list-wrapped the arguments of any multi-value
predicate
except `between` and `inside`, but `outside` was omitted from that exclusion.
`outside` takes exactly two arguments in the grammar (like
`between`/`inside`), so
they must be comma-separated, not wrapped in a list.
Use case: an anomaly-detection query finds sensor readings outside the normal
operating range of 18 to 65 (too cold or too hot).
Before:
```go
readings, err := g.V().Has("temperature", gremlingo.P.Outside(18,
65)).ToList()
// generated gremlin-lang: g.V().has("temperature",outside([18,65]))
// err: server-side parse error - "outside([18,65])" is not valid
gremlin-lang
// readings: nil
```
The query never runs. Because the identical query works from the Java,
Python,
.NET, and JavaScript drivers, the failure looks like a server or environment
problem rather than a driver bug, and `P.Outside` is effectively unusable
from Go.
After:
```go
readings, err := g.V().Has("temperature", gremlingo.P.Outside(18,
65)).ToList()
// generated gremlin-lang: g.V().has("temperature",outside(18,65))
// err: nil
// readings: the out-of-range vertices, as expected
```
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