Remove explicit dependency on hex-conservative

[tcharding]

The hex crate is re-exported by rust-bitcoin so we can get it from there instead of explicitly depending on it. Doing so reduces the maintenance burden and helps reduce the likelyhood of getting two versions in the dependency graph.

Note however that there is still a single explicit dev dependency that may want to be kept in sync.

[tcharding]

Ugh, this makes the code non-uniform because it grabs hex from bitcoin instead of from bitcoin::hashes. I was going to patch that next but then remembered that I don't know how to use rustfmt in this repo to re-order the import statements. So we could either:

1. Re-do this PR use bitcoin::hashes::hex
2. Teach Tobin how to run the formatter

(If we do (2) I can revive #3146.)

[TheBlueMatt]

Teach Tobin how to run the formatter

Yea, sorry, we weren't really good about that. Fixing in #3226

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 1 line in your changes missing coverage. Please review.

Project coverage is 89.84%. Comparing base (fd8f4ac) to head (eac1b87).
Report is 8 commits behind head on main.

Files	Patch %	Lines
lightning/src/routing/gossip.rs	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3210      +/-   ##
==========================================
+ Coverage   89.74%   89.84%   +0.10%     
==========================================
  Files         122      122              
  Lines      101875   102846     +971     
  Branches   101875   102846     +971     
==========================================
+ Hits        91423    92407     +984     
- Misses       7767     7776       +9     
+ Partials     2685     2663      -22     

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[tnull]

LGTM

[TheBlueMatt]

Thanks!

[TheBlueMatt]

Oops, this doesn't build because of the extern crate hex; line in fuzz/src/lib.rs. Also, the remaining dependency on hex in lightning-invoice can just be removed as its not used directly anywhere:

diff --git a/lightning-invoice/Cargo.toml b/lightning-invoice/Cargo.toml
index d89f8d08e..94b307167 100644
--- a/lightning-invoice/Cargo.toml
+++ b/lightning-invoice/Cargo.toml
@@ -28,7 +28,6 @@ bitcoin = { version = "0.31.2", default-features = false }

 [dev-dependencies]
 lightning = { version = "0.0.123-beta", path = "../lightning", default-features = false, features = ["_test_utils"] }
-hex = { package = "hex-conservative", version = "0.1.1", default-features = false }
 serde_json = { version = "1"}
 hashbrown = { version = "0.13", default-features = false }

[tcharding]

I don't know what to make of the failing CI jobs, there is a ! but no output as to why they failed?

[tnull]

I don't know what to make of the failing CI jobs, there is a ! but no output as to why they failed?

Yeah, unfortunately they started failing a few days ago without yielding any error output, and so far nobody has found the time to dig in what makes github fail them..

[tcharding]

Bizzarre, can you tag me please if it turns out to be something github related that we might run into in rust-bitcoin also.