From fcbc9378323065f6f0b3fdf143afec2a2ee3cf99 Mon Sep 17 00:00:00 2001
From: obchain <riteshnikhoriya94@gmail.com>
Date: Sun, 26 Apr 2026 13:48:35 +0530
Subject: [PATCH] fix(config): swap dead BTCB Chainlink address for live
 AggregatorV3 (closes #109)
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The address shipped in #109's "fix" — 0x264990fbd0…1f0 — has no
bytecode on BSC mainnet. `cast code` returns 0x against both dRPC
and bsc-dataseed.binance.org, so every `decimals()` / `latestRoundData()`
call against it abi-decodes garbage and BTCB-collateral positions
have been silently unpriceable since #35 landed.

Discovered the live address by walking the on-chain Venus oracle path:

  ResilientOracle (0x6592b5DE…)
    → ChainlinkOracle facet (0x1B210344…)
      → tokenConfigs(BTCB) → 0x8ECF7dE377F788A813F5215668E282556b35f300

Verified live against bsc.drpc.org:

  cast code        → 19,145 bytes of bytecode
  decimals()       → 18  (Venus uses 18-decimal Chainlink wrappers,
                          not the standard 8-decimal feeds)
  description()    → "BTC / USD"
  latestRoundData  → answer ≈ 78,090e18 (= $78,090), fresh round

Confirmed Chainlink-ops-owned: feed `owner()` is 0xcb6754D5…, the
same multisig that owns the BNB/USD canonical feed.

PriceCache (`crates/charon-scanner/src/oracle.rs:33,59`) reads
`decimals()` per feed at startup and `CachedPrice::scaled_to`
rescales to a target — the 8→18 decimal difference is invisible to
consumers, no Rust changes required.

Same swap applied to `config/fork.toml` since the fork profile pins
mainnet block forks and would have hit the same garbage decode.

Comment block above [chainlink.bnb] in default.toml records the
Venus-oracle discovery path so future reviewers don't have to walk
it again.

Adjacent finding (separate issue recommended): the other four
[chainlink.bnb] entries (BNB, ETH, USDT, USDC) were sourced the same
way from docs.chain.link. Given one of five was bytecodeless, the
remaining four warrant the same cast-code/decimals/description sanity
check.
---
 config/default.toml | 13 ++++++++++++-
 config/fork.toml    |  2 +-
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/config/default.toml b/config/default.toml
index 84c731e..57b8e53 100644
--- a/config/default.toml
+++ b/config/default.toml
@@ -90,9 +90,20 @@ bind       = "127.0.0.1:9091"
 # ── Chainlink price feeds (per chain, per asset symbol) ───────────────────
 # Only feeds listed here are polled by the PriceCache. Add more as new
 # Venus markets become relevant. Feed addresses from docs.chain.link.
+#
+# Note on BTCB: docs.chain.link historically advertised the 8-decimal
+# proxy 0x264990fb…1f0 as "BTC / USD" on BSC, but that address has no
+# bytecode on mainnet today (decimals()/latestRoundData() abi-decode
+# garbage). The address used below was discovered by walking Venus's
+# ResilientOracle (0x6592b5DE…) → ChainlinkOracle facet (0x1B210344…)
+# → tokenConfigs(BTCB) and then verified to be Chainlink-owned by
+# matching its `owner()` (0xcb6754D5…) against the BNB/USD canonical
+# feed's owner. It is an 18-decimal aggregator; PriceCache reads
+# `decimals()` per feed and `CachedPrice::scaled_to` rescales, so the
+# 8-vs-18 difference is invisible to consumers.
 [chainlink.bnb]
 BNB  = "0x0567F2323251f0Aab15c8dFb1967E4e8A7D42aeE"
-BTCB = "0x264990fbd0A4796A3E3d8E37022BdAf1A5a4C1f0" # BTC / USD (canonical, docs.chain.link)
+BTCB = "0x8ECF7dE377F788A813F5215668E282556b35f300" # BTC / USD — 18-dec AggregatorV3, Chainlink-ops-owned (#109)
 ETH  = "0x9ef1B8c0E4F7dc8bF5719Ea496883DC6401d5b2e"
 USDT = "0xB97Ad0E74fa7d920791E90258A6E2085088b4320"
 USDC = "0x51597f405303C4377E36123cBc172b13269EA163"
diff --git a/config/fork.toml b/config/fork.toml
index d542a5f..9a3efad 100644
--- a/config/fork.toml
+++ b/config/fork.toml
@@ -96,7 +96,7 @@ bind    = "127.0.0.1:9091"
 # Mainnet feed addresses resolve against the fork.
 [chainlink.bnb]
 BNB  = "0x0567F2323251f0Aab15c8dFb1967E4e8A7D42aeE"
-BTCB = "0x264990fbd0A4796A3E3d8E37022BdAf1A5a4C1f0"
+BTCB = "0x8ECF7dE377F788A813F5215668E282556b35f300" # BTC / USD — 18-dec AggregatorV3, Chainlink-ops-owned (#109)
 ETH  = "0x9ef1B8c0E4F7dc8bF5719Ea496883DC6401d5b2e"
 USDT = "0xB97Ad0E74fa7d920791E90258A6E2085088b4320"
 USDC = "0x51597f405303C4377E36123cBc172b13269EA163"