rueidiscompat: fix HSetEXWithArgs panic when Condition is unset

[jtlang]

Summary

HSetEXWithArgs only built the underlying HSETEX command inside the Condition == HSetEXFNX / Condition == HSetEXFXX branches. Since Condition is optional (per HSetEXOptions), leaving it unset to apply only ExpirationType (e.g. EX/PX/KEEPTTL) left the command builder at its zero value, causing a nil pointer dereference in HsetexFieldValue.FieldValue.

Repro

adapter.HSetEXWithArgs(ctx, "key", &rueidiscompat.HSetEXOptions{
    ExpirationType: rueidiscompat.HSetEXExpirationEX,
    ExpirationVal:  100,
}, "field1", "value1")

panics with invalid memory address or nil pointer dereference in gen_hash.go:HsetexFieldValue.FieldValue.

Fix

Add the missing no-condition path in the Condition switch, building directly off Hsetex().Key(key) (no .Fnx()/.Fxx()). Also added a default case to each ExpirationType switch so an unset expiration falls through to .Fields() instead of leaving the command unset.

Test plan

• Added a regression test (should HSetEXWithArgs apply ExpirationType without a Condition) in the existing Redis 8.6+ commands suite, covering set + get + TTL round-trip.
• Verified the new test panics on main (before the fix) and passes after.
• go build/go vet clean; existing hash-command specs still pass.

---

Note

Low Risk
Localized fix to Redis hash command adapter command-building; behavior change only affects previously broken call paths.

Overview
Fixes a nil pointer panic in HSetEXWithArgs when HSetEXOptions.Condition is left unset but ExpirationType (e.g. EX) is set—previously only FNX/FXX branches built the HSETEX command.

The adapter now handles the no-condition path by building Hsetex().Key(key) with the appropriate expiration modifiers, and adds default fallbacks on each ExpirationType switch (including FNX/FXX) so the field builder is always initialized before FieldValue runs.

A regression test covers set/get/TTL when only expiration options are provided.

^{Reviewed by Cursor Bugbot for commit ff969bc. Bugbot is set up for automated code reviews on this repo. Configure here.}

[rueian]

Hi @jtlang, is the new behavior aligned with go-redis?

[jtlang]

@rueian Yes, this will bring it in line with go-redis behavior