From 8132137a0578d8f0ad29952993b6840f7b2d0500 Mon Sep 17 00:00:00 2001
From: Jake Shadle <jake.shadle@embark-studios.com>
Date: Thu, 28 Nov 2024 14:21:14 +0100
Subject: [PATCH] Warn on skip without duplicates (#726)

- **Update rustls and url**
- **Update gix and tame-index**
- **Add unnecessary-skip diagnostic**

Resolves: #725
---
 CHANGELOG.md                                  |   3 +
 Cargo.lock                                    | 260 +++++++++---------
 Cargo.toml                                    |   6 +-
 deny.toml                                     |   1 +
 docs/src/checks/bans/diags.md                 |   4 +
 src/bans.rs                                   |  62 ++++-
 src/bans/diags.rs                             |  21 ++
 src/bans/graph.rs                             |  15 +-
 .../cargo_deny__diag__test__codes_unique.snap |   2 +
 tests/bans.rs                                 |  27 ++
 .../bans__unused_skips_generate_warnings.snap | 241 ++++++++++++++++
 11 files changed, 491 insertions(+), 151 deletions(-)
 create mode 100644 tests/snapshots/bans__unused_skips_generate_warnings.snap

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2e71b06a..cc96d7ea 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - [PR#721](https://github.com/EmbarkStudios/cargo-deny/pull/721) updated `rust-version` to 1.81.0 to accurately reflect the minimum rust version required to compile, resolving [#720](https://github.com/EmbarkStudios/cargo-deny/issues/720).
 - [PR#722](https://github.com/EmbarkStudios/cargo-deny/pull/722) updated the SPDX license list to 3.25.0.
 
+### Fixed
+- [PR#726](https://github.com/EmbarkStudios/cargo-deny/pull/726) resolved [#725](https://github.com/EmbarkStudios/cargo-deny/issues/725) by adding the `unnecessary-skip` diagnostic, emitted when there is a `skip` configured for a crate that only has one version in the graph.
+
 ## [0.16.2] - 2024-11-15
 ### Fixed
 - [PR#703](https://github.com/EmbarkStudios/cargo-deny/pull/703) resolved [#696](https://github.com/EmbarkStudios/cargo-deny/issues/696) by no longer emitting errors when failing to deserialize deprecated fields, and removed some lingering documentation that wasn't removed in [PR#611](https://github.com/EmbarkStudios/cargo-deny/pull/611).
diff --git a/Cargo.lock b/Cargo.lock
index f26bb538..2e06b503 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -312,9 +312,9 @@ dependencies = [
 
 [[package]]
 name = "cfg-expr"
-version = "0.17.0"
+version = "0.17.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d0890061c4d3223e7267f3bad2ec40b997d64faac1c2815a4a9d95018e2b9e9c"
+checksum = "c360837f8f19e2e4468275138f1c0dec1647d1e17bb7c0215fe3cd7530e93c25"
 dependencies = [
  "smallvec",
  "target-lexicon",
@@ -769,9 +769,9 @@ checksum = "07e28edb80900c19c28f1072f2e8aeca7fa06b23cd4169cefe1af5aa3260783f"
 
 [[package]]
 name = "gix"
-version = "0.67.0"
+version = "0.68.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c7d3e78ddac368d3e3bfbc2862bc2aafa3d89f1b15fed898d9761e1ec6f3f17f"
+checksum = "b04c66359b5e17f92395abc433861df0edf48f39f3f590818d1d7217327dd6a1"
 dependencies = [
  "gix-actor",
  "gix-attributes",
@@ -818,28 +818,28 @@ dependencies = [
  "parking_lot",
  "signal-hook",
  "smallvec",
- "thiserror 1.0.69",
+ "thiserror 2.0.3",
 ]
 
 [[package]]
 name = "gix-actor"
-version = "0.33.0"
+version = "0.33.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "59226ef06661c756e664b46b1d3b2c198f6adc5407a484c086d0171108a70027"
+checksum = "32b24171f514cef7bb4dfb72a0b06dacf609b33ba8ad2489d4c4559a03b7afb3"
 dependencies = [
  "bstr",
  "gix-date",
  "gix-utils",
  "itoa",
- "thiserror 1.0.69",
+ "thiserror 2.0.3",
  "winnow",
 ]
 
 [[package]]
 name = "gix-attributes"
-version = "0.23.0"
+version = "0.23.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "31a102d201ef0e5a848458a82292581e7641e52f0f52e693b6cbdd05a652c029"
+checksum = "ddf9bf852194c0edfe699a2d36422d2c1f28f73b7c6d446c3f0ccd3ba232cadc"
 dependencies = [
  "bstr",
  "gix-glob",
@@ -848,33 +848,33 @@ dependencies = [
  "gix-trace",
  "kstring",
  "smallvec",
- "thiserror 1.0.69",
+ "thiserror 2.0.3",
  "unicode-bom",
 ]
 
 [[package]]
 name = "gix-bitmap"
-version = "0.2.12"
+version = "0.2.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "10f78312288bd02052be5dbc2ecbc342c9f4eb791986d86c0a5c06b92dc72efa"
+checksum = "d48b897b4bbc881aea994b4a5bbb340a04979d7be9089791304e04a9fbc66b53"
 dependencies = [
- "thiserror 1.0.69",
+ "thiserror 2.0.3",
 ]
 
 [[package]]
 name = "gix-chunk"
-version = "0.4.9"
+version = "0.4.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6c28b58ba04f0c004722344390af9dbc85888fbb84be1981afb934da4114d4cf"
+checksum = "c6ffbeb3a5c0b8b84c3fe4133a6f8c82fa962f4caefe8d0762eced025d3eb4f7"
 dependencies = [
- "thiserror 1.0.69",
+ "thiserror 2.0.3",
 ]
 
 [[package]]
 name = "gix-command"
-version = "0.3.10"
+version = "0.3.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c201d2b9e9cce2365a6638fd0a966f751ed92d74be5c0727ac331e6a29ef5846"
+checksum = "6d7d6b8f3a64453fd7e8191eb80b351eb7ac0839b40a1237cd2c137d5079fe53"
 dependencies = [
  "bstr",
  "gix-path",
@@ -884,23 +884,23 @@ dependencies = [
 
 [[package]]
 name = "gix-commitgraph"
-version = "0.25.0"
+version = "0.25.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "41db900b189e62dc61575f06fdf1a3b6901d264a99be9d32b286af6b2e3984e1"
+checksum = "a8da6591a7868fb2b6dabddea6b09988b0b05e0213f938dbaa11a03dd7a48d85"
 dependencies = [
  "bstr",
  "gix-chunk",
  "gix-features",
  "gix-hash",
  "memmap2",
- "thiserror 1.0.69",
+ "thiserror 2.0.3",
 ]
 
 [[package]]
 name = "gix-config"
-version = "0.41.0"
+version = "0.42.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0bedd1bf1c7b994be9d57207e8e0de79016c05e2e8701d3015da906e65ac445e"
+checksum = "6649b406ca1f99cb148959cf00468b231f07950f8ec438cc0903cda563606f19"
 dependencies = [
  "bstr",
  "gix-config-value",
@@ -912,29 +912,29 @@ dependencies = [
  "memchr",
  "once_cell",
  "smallvec",
- "thiserror 1.0.69",
+ "thiserror 2.0.3",
  "unicode-bom",
  "winnow",
 ]
 
 [[package]]
 name = "gix-config-value"
-version = "0.14.9"
+version = "0.14.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f3de3fdca9c75fa4b83a76583d265fa49b1de6b088ebcd210749c24ceeb74660"
+checksum = "49aaeef5d98390a3bcf9dbc6440b520b793d1bf3ed99317dc407b02be995b28e"
 dependencies = [
  "bitflags",
  "bstr",
  "gix-path",
  "libc",
- "thiserror 1.0.69",
+ "thiserror 2.0.3",
 ]
 
 [[package]]
 name = "gix-credentials"
-version = "0.25.0"
+version = "0.25.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d713bac4bf7df5801012285366dae6625d675baec4ba6e443d64e83559bec068"
+checksum = "2be87bb8685fc7e6e7032ef71c45068ffff609724a0c897b8047fde10db6ae71"
 dependencies = [
  "bstr",
  "gix-command",
@@ -944,38 +944,38 @@ dependencies = [
  "gix-sec",
  "gix-trace",
  "gix-url",
- "thiserror 1.0.69",
+ "thiserror 2.0.3",
 ]
 
 [[package]]
 name = "gix-date"
-version = "0.9.1"
+version = "0.9.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d10d543ac13c97292a15e8e8b7889cd006faf739777437ed95362504b8fe81a0"
+checksum = "691142b1a34d18e8ed6e6114bc1a2736516c5ad60ef3aa9bd1b694886e3ca92d"
 dependencies = [
  "bstr",
  "itoa",
  "jiff",
- "thiserror 1.0.69",
+ "thiserror 2.0.3",
 ]
 
 [[package]]
 name = "gix-diff"
-version = "0.47.0"
+version = "0.48.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c9850fd0c15af113db6f9e130d13091ba0d3754e570a2afdff9e2f3043da260e"
+checksum = "a327be31a392144b60ab0b1c863362c32a1c8f7effdfa2141d5d5b6b916ef3bf"
 dependencies = [
  "bstr",
  "gix-hash",
  "gix-object",
- "thiserror 1.0.69",
+ "thiserror 2.0.3",
 ]
 
 [[package]]
 name = "gix-discover"
-version = "0.36.0"
+version = "0.37.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c522e31f458f50af09dfb014e10873c5378f702f8049c96f508989aad59671f6"
+checksum = "83bf6dfa4e266a4a9becb4d18fc801f92c3f7cc6c433dd86fdadbcf315ffb6ef"
 dependencies = [
  "bstr",
  "dunce",
@@ -984,14 +984,14 @@ dependencies = [
  "gix-path",
  "gix-ref",
  "gix-sec",
- "thiserror 1.0.69",
+ "thiserror 2.0.3",
 ]
 
 [[package]]
 name = "gix-features"
-version = "0.39.0"
+version = "0.39.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8e0eb9efdf96c35c0bed7596d1bef2d4ce6360a1d09738001f9d3e402aa7ba3e"
+checksum = "7d85d673f2e022a340dba4713bed77ef2cf4cd737d2f3e0f159d45e0935fd81f"
 dependencies = [
  "bytes",
  "crc32fast",
@@ -1003,15 +1003,15 @@ dependencies = [
  "once_cell",
  "prodash",
  "sha1_smol",
- "thiserror 1.0.69",
+ "thiserror 2.0.3",
  "walkdir",
 ]
 
 [[package]]
 name = "gix-filter"
-version = "0.14.0"
+version = "0.15.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6b37f82359a4485770ed8993ae715ced1bf674f2a63e45f5a0786d38310665ea"
+checksum = "5108cc58d58b27df10ac4de7f31b2eb96d588a33e5eba23739b865f5d8db7995"
 dependencies = [
  "bstr",
  "encoding_rs",
@@ -1025,7 +1025,7 @@ dependencies = [
  "gix-trace",
  "gix-utils",
  "smallvec",
- "thiserror 1.0.69",
+ "thiserror 2.0.3",
 ]
 
 [[package]]
@@ -1041,9 +1041,9 @@ dependencies = [
 
 [[package]]
 name = "gix-glob"
-version = "0.17.0"
+version = "0.17.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "254b5101cf7facc00d9b5ff564cf46302ca76695cca23d33bc958a707b6fc857"
+checksum = "aaf69a6bec0a3581567484bf99a4003afcaf6c469fd4214352517ea355cf3435"
 dependencies = [
  "bitflags",
  "bstr",
@@ -1053,12 +1053,12 @@ dependencies = [
 
 [[package]]
 name = "gix-hash"
-version = "0.15.0"
+version = "0.15.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "952c3a29f1bc1007cc901abce7479943abfa42016db089de33d0a4fa3c85bfe8"
+checksum = "0b5eccc17194ed0e67d49285e4853307e4147e95407f91c1c3e4a13ba9f4e4ce"
 dependencies = [
  "faster-hex",
- "thiserror 1.0.69",
+ "thiserror 2.0.3",
 ]
 
 [[package]]
@@ -1074,9 +1074,9 @@ dependencies = [
 
 [[package]]
 name = "gix-ignore"
-version = "0.12.0"
+version = "0.12.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ba55a9b582dc26a639875497615959a8127ac5c37b2426dc50f037fada33a4b7"
+checksum = "b6b1fb24d2a4af0aa7438e2771d60c14a80cf2c9bd55c29cf1712b841f05bb8a"
 dependencies = [
  "bstr",
  "gix-glob",
@@ -1087,9 +1087,9 @@ dependencies = [
 
 [[package]]
 name = "gix-index"
-version = "0.36.0"
+version = "0.37.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "27619009ca1ea33fd885041273f5fa5a09163a5c1d22a913b28d7b985e66fe29"
+checksum = "270645fd20556b64c8ffa1540d921b281e6994413a0ca068596f97e9367a257a"
 dependencies = [
  "bitflags",
  "bstr",
@@ -1110,7 +1110,7 @@ dependencies = [
  "memmap2",
  "rustix",
  "smallvec",
- "thiserror 1.0.69",
+ "thiserror 2.0.3",
 ]
 
 [[package]]
@@ -1126,9 +1126,9 @@ dependencies = [
 
 [[package]]
 name = "gix-negotiate"
-version = "0.16.0"
+version = "0.17.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "414806291838c3349ea939c6d840ff854f84cd29bd3dde8f904f60b0e5b7d0bd"
+checksum = "d27f830a16405386e9c83b9d5be8261fe32bbd6b3caf15bd1b284c6b2b7ef1a8"
 dependencies = [
  "bitflags",
  "gix-commitgraph",
@@ -1137,14 +1137,14 @@ dependencies = [
  "gix-object",
  "gix-revwalk",
  "smallvec",
- "thiserror 1.0.69",
+ "thiserror 2.0.3",
 ]
 
 [[package]]
 name = "gix-object"
-version = "0.45.0"
+version = "0.46.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2a77b6e7753d298553d9ae8b1744924481e7a49170983938bb578dccfbc6fc1a"
+checksum = "65d93e2bbfa83a307e47f45e45de7b6c04d7375a8bd5907b215f4bf45237d879"
 dependencies = [
  "bstr",
  "gix-actor",
@@ -1156,15 +1156,15 @@ dependencies = [
  "gix-validate",
  "itoa",
  "smallvec",
- "thiserror 1.0.69",
+ "thiserror 2.0.3",
  "winnow",
 ]
 
 [[package]]
 name = "gix-odb"
-version = "0.64.0"
+version = "0.65.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0bb86aadf7f1b2f980601b4fc94309706f9700f8008f935dc512d556c9e60f61"
+checksum = "93bed6e1b577c25a6bb8e6ecbf4df525f29a671ddf5f2221821a56a8dbeec4e3"
 dependencies = [
  "arc-swap",
  "gix-date",
@@ -1178,14 +1178,14 @@ dependencies = [
  "gix-quote",
  "parking_lot",
  "tempfile",
- "thiserror 1.0.69",
+ "thiserror 2.0.3",
 ]
 
 [[package]]
 name = "gix-pack"
-version = "0.54.0"
+version = "0.55.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "363e6e59a855ba243672408139db68e2478126cdcfeabb420777df4a1f20026b"
+checksum = "9b91fec04d359544fecbb8e85117ec746fbaa9046ebafcefb58cb74f20dc76d4"
 dependencies = [
  "clru",
  "gix-chunk",
@@ -1198,51 +1198,51 @@ dependencies = [
  "memmap2",
  "parking_lot",
  "smallvec",
- "thiserror 1.0.69",
+ "thiserror 2.0.3",
 ]
 
 [[package]]
 name = "gix-packetline"
-version = "0.18.0"
+version = "0.18.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5f14a110eb16e27b4ebdae4ca8b389df3ad637d3020077e6b606b1d078745b65"
+checksum = "8a720e5bebf494c3ceffa85aa89f57a5859450a0da0a29ebe89171e23543fa78"
 dependencies = [
  "bstr",
  "faster-hex",
  "gix-trace",
- "thiserror 1.0.69",
+ "thiserror 2.0.3",
 ]
 
 [[package]]
 name = "gix-packetline-blocking"
-version = "0.18.0"
+version = "0.18.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "decace940e8ba8e29d29b73b843a6cbae67503887f3e5fb7e688d0f4f6ee0757"
+checksum = "ce9004ce1bc00fd538b11c1ec8141a1558fb3af3d2b7ac1ac5c41881f9e42d2a"
 dependencies = [
  "bstr",
  "faster-hex",
  "gix-trace",
- "thiserror 1.0.69",
+ "thiserror 2.0.3",
 ]
 
 [[package]]
 name = "gix-path"
-version = "0.10.12"
+version = "0.10.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c04e5a94fdb56b1e91eb7df2658ad16832428b8eeda24ff1a0f0288de2bce554"
+checksum = "afc292ef1a51e340aeb0e720800338c805975724c1dfbd243185452efd8645b7"
 dependencies = [
  "bstr",
  "gix-trace",
  "home",
  "once_cell",
- "thiserror 1.0.69",
+ "thiserror 2.0.3",
 ]
 
 [[package]]
 name = "gix-pathspec"
-version = "0.8.0"
+version = "0.8.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "70f02bf7625dbf15bf9fedbeace2ac1ce1c5177806bdbc24c441d664c75c00e4"
+checksum = "4c472dfbe4a4e96fcf7efddcd4771c9037bb4fdea2faaabf2f4888210c75b81e"
 dependencies = [
  "bitflags",
  "bstr",
@@ -1250,27 +1250,27 @@ dependencies = [
  "gix-config-value",
  "gix-glob",
  "gix-path",
- "thiserror 1.0.69",
+ "thiserror 2.0.3",
 ]
 
 [[package]]
 name = "gix-prompt"
-version = "0.8.8"
+version = "0.8.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "57944bbdb87f7a9893907032276e99ff4eba3640d8db1bdfb1eba8c07edfd006"
+checksum = "7a7822afc4bc9c5fbbc6ce80b00f41c129306b7685cac3248dbfa14784960594"
 dependencies = [
  "gix-command",
  "gix-config-value",
  "parking_lot",
  "rustix",
- "thiserror 1.0.69",
+ "thiserror 2.0.3",
 ]
 
 [[package]]
 name = "gix-protocol"
-version = "0.46.0"
+version = "0.46.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ac4ebf25f20ac6055728eaa80951acf2cf83948a64af6565b98e7d42b1ab6691"
+checksum = "7a7e7e51a0dea531d3448c297e2fa919b2de187111a210c324b7e9f81508b8ca"
 dependencies = [
  "bstr",
  "gix-credentials",
@@ -1280,26 +1280,26 @@ dependencies = [
  "gix-transport",
  "gix-utils",
  "maybe-async",
- "thiserror 1.0.69",
+ "thiserror 2.0.3",
  "winnow",
 ]
 
 [[package]]
 name = "gix-quote"
-version = "0.4.13"
+version = "0.4.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f89f9a1525dcfd9639e282ea939f5ab0d09d93cf2b90c1fc6104f1b9582a8e49"
+checksum = "64a1e282216ec2ab2816cd57e6ed88f8009e634aec47562883c05ac8a7009a63"
 dependencies = [
  "bstr",
  "gix-utils",
- "thiserror 1.0.69",
+ "thiserror 2.0.3",
 ]
 
 [[package]]
 name = "gix-ref"
-version = "0.48.0"
+version = "0.49.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a47385e71fa2d9da8c35e642ef4648808ddf0a52bc93425879088c706dfeaea2"
+checksum = "1eae462723686272a58f49501015ef7c0d67c3e042c20049d8dd9c7eff92efde"
 dependencies = [
  "gix-actor",
  "gix-features",
@@ -1312,29 +1312,29 @@ dependencies = [
  "gix-utils",
  "gix-validate",
  "memmap2",
- "thiserror 1.0.69",
+ "thiserror 2.0.3",
  "winnow",
 ]
 
 [[package]]
 name = "gix-refspec"
-version = "0.26.0"
+version = "0.27.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0022038a09d80d9abf773be8efcbb502868d97f6972b8633bfb52ab6edaac442"
+checksum = "00c056bb747868c7eb0aeb352c9f9181ab8ca3d0a2550f16470803500c6c413d"
 dependencies = [
  "bstr",
  "gix-hash",
  "gix-revision",
  "gix-validate",
  "smallvec",
- "thiserror 1.0.69",
+ "thiserror 2.0.3",
 ]
 
 [[package]]
 name = "gix-revision"
-version = "0.30.0"
+version = "0.31.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4ee8eb4088fece3562af4a5d751e069f90e93345524ad730512185234c4b55f1"
+checksum = "44488e0380847967bc3e3cacd8b22652e02ea1eb58afb60edd91847695cd2d8d"
 dependencies = [
  "bstr",
  "gix-commitgraph",
@@ -1342,14 +1342,14 @@ dependencies = [
  "gix-hash",
  "gix-object",
  "gix-revwalk",
- "thiserror 1.0.69",
+ "thiserror 2.0.3",
 ]
 
 [[package]]
 name = "gix-revwalk"
-version = "0.16.0"
+version = "0.17.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e6c9a9496da98d36ff19063a8576bf09a87425583b709a56dc5594fffa9d39b2"
+checksum = "510026fc32f456f8f067d8f37c34088b97a36b2229d88a6a5023ef179fcb109d"
 dependencies = [
  "gix-commitgraph",
  "gix-date",
@@ -1357,14 +1357,14 @@ dependencies = [
  "gix-hashtable",
  "gix-object",
  "smallvec",
- "thiserror 1.0.69",
+ "thiserror 2.0.3",
 ]
 
 [[package]]
 name = "gix-sec"
-version = "0.10.9"
+version = "0.10.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a2007538eda296445c07949cf04f4a767307d887184d6b3e83e2d636533ddc6e"
+checksum = "a8b876ef997a955397809a2ec398d6a45b7a55b4918f2446344330f778d14fd6"
 dependencies = [
  "bitflags",
  "gix-path",
@@ -1374,9 +1374,9 @@ dependencies = [
 
 [[package]]
 name = "gix-submodule"
-version = "0.15.0"
+version = "0.16.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3ed099621873cd36c580fc822176a32a7e50fef15a5c2ed81aaa087296f0497a"
+checksum = "a2455f8c0fcb6ebe2a6e83c8f522d30615d763eb2ef7a23c7d929f9476e89f5c"
 dependencies = [
  "bstr",
  "gix-config",
@@ -1384,7 +1384,7 @@ dependencies = [
  "gix-pathspec",
  "gix-refspec",
  "gix-url",
- "thiserror 1.0.69",
+ "thiserror 2.0.3",
 ]
 
 [[package]]
@@ -1410,9 +1410,9 @@ checksum = "04bdde120c29f1fc23a24d3e115aeeea3d60d8e65bab92cc5f9d90d9302eb952"
 
 [[package]]
 name = "gix-transport"
-version = "0.43.0"
+version = "0.43.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4c485a345f41b8c0256cb86e95ed93e0692d203fd6c769b0433f7352c13608ad"
+checksum = "39a1a41357b7236c03e0c984147f823d87c3e445a8581bac7006df141577200b"
 dependencies = [
  "base64",
  "bstr",
@@ -1424,14 +1424,14 @@ dependencies = [
  "gix-sec",
  "gix-url",
  "reqwest",
- "thiserror 1.0.69",
+ "thiserror 2.0.3",
 ]
 
 [[package]]
 name = "gix-traverse"
-version = "0.42.0"
+version = "0.43.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f20f1b13cc4fa6ba92b24e6aa0c2fb6a34beb4458ef88c6300212db504e818df"
+checksum = "3ff2ec9f779680f795363db1c563168b32b8d6728ec58564c628e85c92d29faf"
 dependencies = [
  "bitflags",
  "gix-commitgraph",
@@ -1441,19 +1441,19 @@ dependencies = [
  "gix-object",
  "gix-revwalk",
  "smallvec",
- "thiserror 1.0.69",
+ "thiserror 2.0.3",
 ]
 
 [[package]]
 name = "gix-url"
-version = "0.28.0"
+version = "0.28.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "33e7c297c3265015c133a2c02199610b6e1373a09dc4be057d0c1b5285737f06"
+checksum = "e09f97db3618fb8e473d7d97e77296b50aaee0ddcd6a867f07443e3e87391099"
 dependencies = [
  "bstr",
  "gix-features",
  "gix-path",
- "thiserror 1.0.69",
+ "thiserror 2.0.3",
  "url",
 ]
 
@@ -1469,19 +1469,19 @@ dependencies = [
 
 [[package]]
 name = "gix-validate"
-version = "0.9.1"
+version = "0.9.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e187b263461bc36cea17650141567753bc6207d036cedd1de6e81a52f277ff68"
+checksum = "cd520d09f9f585b34b32aba1d0b36ada89ab7fefb54a8ca3fe37fc482a750937"
 dependencies = [
  "bstr",
- "thiserror 1.0.69",
+ "thiserror 2.0.3",
 ]
 
 [[package]]
 name = "gix-worktree"
-version = "0.37.0"
+version = "0.38.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0d345e5b523550fe4fa0e912bf957de752011ccfc87451968fda1b624318f29c"
+checksum = "756dbbe15188fa22540d5eab941f8f9cf511a5364d5aec34c88083c09f4bea13"
 dependencies = [
  "bstr",
  "gix-attributes",
@@ -1498,9 +1498,9 @@ dependencies = [
 
 [[package]]
 name = "gix-worktree-state"
-version = "0.14.0"
+version = "0.15.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5e72b00e02f3bd737caae9c20a98e70749f42ae18c8f0b68aac3210b42a0b8da"
+checksum = "4ebd5eead61d37b334bc31810c9980aa72d659044513cae0e342a88fed2c22ba"
 dependencies = [
  "bstr",
  "gix-features",
@@ -1513,7 +1513,7 @@ dependencies = [
  "gix-path",
  "gix-worktree",
  "io-close",
- "thiserror 1.0.69",
+ "thiserror 2.0.3",
 ]
 
 [[package]]
@@ -2485,9 +2485,9 @@ dependencies = [
 
 [[package]]
 name = "rustls"
-version = "0.23.16"
+version = "0.23.19"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "eee87ff5d9b36712a58574e12e9f0ea80f915a5b0ac518d322b24a465617925e"
+checksum = "934b404430bb06b3fae2cba809eb45a1ab1aecd64491213d7c3301b88393f8d1"
 dependencies = [
  "once_cell",
  "ring",
@@ -2901,9 +2901,9 @@ dependencies = [
 
 [[package]]
 name = "tame-index"
-version = "0.15.0"
+version = "0.16.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2e84f5c909182129ef064424ed6eeef4210db99c35b9bd2dc36c230c1544ec66"
+checksum = "c0150bc4fba57808bbfc13a6f5d058f8bd83b485c909b67e4d14736f065def51"
 dependencies = [
  "bytes",
  "camino",
@@ -2920,7 +2920,7 @@ dependencies = [
  "serde_json",
  "sha2",
  "smol_str",
- "thiserror 1.0.69",
+ "thiserror 2.0.3",
  "tokio",
  "toml-span",
  "twox-hash",
@@ -3218,9 +3218,9 @@ checksum = "8ecb6da28b8a351d773b68d5825ac39017e680750f980f3a1a85cd8dd28a47c1"
 
 [[package]]
 name = "url"
-version = "2.5.3"
+version = "2.5.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8d157f1b96d14500ffdc1f10ba712e780825526c03d9a49b4d0324b0d9113ada"
+checksum = "32f8b686cadd1473f4bd0117a5d28d36b1ade384ea9b5069a1c40aefed7fda60"
 dependencies = [
  "form_urlencoded",
  "idna",
diff --git a/Cargo.toml b/Cargo.toml
index 3700748e..4b4ff041 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -105,7 +105,7 @@ spdx = "0.10"
 # Lazy
 strum = { version = "0.26", features = ["derive"] }
 # Index retrieval and querying
-tame-index = { version = "0.15", default-features = false, features = [
+tame-index = { version = "0.16", default-features = false, features = [
   "git",
   "local",
   "sparse",
@@ -126,7 +126,7 @@ walkdir = "2.3"
 
 # We clone/fetch advisory databases
 [dependencies.gix]
-version = "0.67"
+version = "0.68"
 default-features = false
 features = [
   "blocking-http-transport-reqwest",
@@ -140,7 +140,7 @@ features = [
 fs_extra = "1.3"
 # Snapshot testing
 insta = { version = "1.41", features = ["json"] }
-tame-index = { version = "0.15", features = ["local-builder"] }
+tame-index = { version = "0.16", features = ["local-builder"] }
 time = { version = "0.3", features = ["serde"] }
 toml-span = { version = "0.3", features = ["serde"] }
 # We use this for creating fake crate directories for crawling license files on disk
diff --git a/deny.toml b/deny.toml
index 931327c3..dcfb4d51 100644
--- a/deny.toml
+++ b/deny.toml
@@ -31,6 +31,7 @@ skip = [
 ]
 skip-tree = [
     { crate = "windows-sys@0.52.0", reason = "a foundational crate for many that bumps far too frequently to ever have a shared version" },
+    { crate = "thiserror@1.0.69", reason = "gix depends on both the 1.0 and 2.0 versions" },
 ]
 
 [sources]
diff --git a/docs/src/checks/bans/diags.md b/docs/src/checks/bans/diags.md
index 37876ae3..916cb838 100644
--- a/docs/src/checks/bans/diags.md
+++ b/docs/src/checks/bans/diags.md
@@ -41,6 +41,10 @@ A [`[workspace.dependencies]`](https://doc.rust-lang.org/cargo/reference/workspa
 
 A crate version in [`bans.skip`](cfg.md#the-skip-field-optional) was not encountered.
 
+### `unnecessary-skip`
+
+A crate specified in [`bans.skip`](cfg.md#the-skip-field-optional) was in the graph, but that crate only had one version, making the `skip` entry useless.
+
 ### `allowed-by-wrapper`
 
 A crate in `bans.deny` was allowed since it was directly depended on by a [`wrappers`](cfg.md#the-wrappers-field-optional) crate.
diff --git a/src/bans.rs b/src/bans.rs
index b3e1cfdf..f1d749f4 100644
--- a/src/bans.rs
+++ b/src/bans.rs
@@ -314,12 +314,16 @@ pub fn check(
 
     struct MultiDetector<'a> {
         name: &'a str,
-        dupes: smallvec::SmallVec<[usize; 2]>,
+        dupes: smallvec::SmallVec<[(usize, bool); 4]>,
+        // Keep track of the crates that actually have > 1 version, regardless of skips
+        // if a skip is encountered for a krate that only has 1 version, warn about it
+        krates_with_dupes: Vec<&'a str>,
     }
 
     let mut multi_detector = MultiDetector {
         name: &ctx.krates.krates().next().unwrap().name,
         dupes: smallvec::SmallVec::new(),
+        krates_with_dupes: Vec::new(),
     };
 
     let filtered_krates = if !multiple_versions_include_dev {
@@ -376,12 +380,25 @@ pub fn check(
             .collect(),
     );
 
-    let report_duplicates = |multi_detector: &MultiDetector<'_>, sink: &mut diag::ErrorSink| {
-        if multi_detector.dupes.len() <= 1 {
+    let report_duplicates = |multi_detector: &mut MultiDetector<'_>, sink: &mut diag::ErrorSink| {
+        let skipped = multi_detector
+            .dupes
+            .iter()
+            .filter(|(_, skipped)| *skipped)
+            .count();
+        if multi_detector.dupes.len() > 1 {
+            multi_detector.krates_with_dupes.push(multi_detector.name);
+        }
+
+        if multi_detector.dupes.len() - skipped <= 1 {
             return;
         }
 
-        let lint_level = if multi_detector.dupes.iter().any(|kindex| {
+        let lint_level = if multi_detector.dupes.iter().any(|(kindex, skipped)| {
+            if *skipped {
+                return false;
+            }
+
             let krate = &ctx.krates[*kindex];
             dmv.matches(krate).is_some()
         }) {
@@ -408,7 +425,11 @@ pub fn check(
 
         let mut kids = smallvec::SmallVec::<[Dupe; 2]>::new();
 
-        for dup in multi_detector.dupes.iter().cloned() {
+        for dup in multi_detector
+            .dupes
+            .iter()
+            .filter_map(|(ind, skipped)| (!*skipped).then_some(*ind))
+        {
             let krate = &ctx.krates[dup];
 
             let span = &ctx.krate_spans.lock_span(&krate.id).total;
@@ -850,6 +871,15 @@ pub fn check(
 
                 if should_add_dupe(&krate.id) {
                     if let Some(matches) = skipped.matches(krate) {
+                        if multi_detector.name != krate.name {
+                            report_duplicates(&mut multi_detector, &mut sink);
+
+                            multi_detector.name = &krate.name;
+                            multi_detector.dupes.clear();
+                        }
+
+                        multi_detector.dupes.push((i, true));
+
                         for rm in matches {
                             pack.push(diags::Skipped {
                                 krate,
@@ -863,13 +893,13 @@ pub fn check(
                         }
                     } else if !tree_skipper.matches(krate, &mut pack) {
                         if multi_detector.name != krate.name {
-                            report_duplicates(&multi_detector, &mut sink);
+                            report_duplicates(&mut multi_detector, &mut sink);
 
                             multi_detector.name = &krate.name;
                             multi_detector.dupes.clear();
                         }
 
-                        multi_detector.dupes.push(i);
+                        multi_detector.dupes.push((i, false));
 
                         'wildcards: {
                             if wildcards != LintLevel::Allow && !krate.is_git_source() {
@@ -958,7 +988,7 @@ pub fn check(
                 }
 
                 if i == last {
-                    report_duplicates(&multi_detector, &mut sink);
+                    report_duplicates(&mut multi_detector, &mut sink);
                 }
 
                 tx.push(i, krate, pack);
@@ -1050,12 +1080,16 @@ pub fn check(
 
     let mut pack = Pack::new(Check::Bans);
 
-    for skip in skip_hit
-        .into_iter()
-        .zip(skipped.0.into_iter())
-        .filter_map(|(hit, skip)| (!hit).then_some(skip))
-    {
-        pack.push(diags::UnmatchedSkip { skip_cfg: &skip });
+    for (hit, skip) in skip_hit.into_iter().zip(skipped.0.into_iter()) {
+        if !hit {
+            pack.push(diags::UnmatchedSkip { skip_cfg: &skip });
+        } else if multi_detector
+            .krates_with_dupes
+            .binary_search(&skip.spec.name.value.as_str())
+            .is_err()
+        {
+            pack.push(diags::UnnecessarySkip { skip_cfg: &skip });
+        }
     }
 
     for wrapper in ban_wrappers
diff --git a/src/bans/diags.rs b/src/bans/diags.rs
index 984abdf0..70a3cfa7 100644
--- a/src/bans/diags.rs
+++ b/src/bans/diags.rs
@@ -28,6 +28,7 @@ pub enum Code {
     Skipped,
     Wildcard,
     UnmatchedSkip,
+    UnnecessarySkip,
     AllowedByWrapper,
     UnmatchedWrapper,
     SkippedByRoot,
@@ -222,6 +223,26 @@ impl<'a> From<UnmatchedSkip<'a>> for Diag {
     }
 }
 
+pub(crate) struct UnnecessarySkip<'a> {
+    pub(crate) skip_cfg: &'a SpecAndReason,
+}
+
+impl<'a> From<UnnecessarySkip<'a>> for Diag {
+    fn from(us: UnnecessarySkip<'a>) -> Self {
+        Diagnostic::new(Severity::Warning)
+            .with_message(format!(
+                "skip '{}' applied to a crate with only one version",
+                us.skip_cfg.spec,
+            ))
+            .with_code(Code::UnnecessarySkip)
+            .with_labels(
+                us.skip_cfg
+                    .to_labels(Some("unnecessary skip configuration")),
+            )
+            .into()
+    }
+}
+
 pub(crate) struct UnusedWrapper {
     pub(crate) wrapper_cfg: CfgCoord,
 }
diff --git a/src/bans/graph.rs b/src/bans/graph.rs
index 9ada5068..4530c667 100644
--- a/src/bans/graph.rs
+++ b/src/bans/graph.rs
@@ -88,7 +88,7 @@ pub(crate) fn create_graph(
     dup_name: &str,
     highlight: GraphHighlight,
     krates: &crate::Krates,
-    dup_ids: &[usize],
+    dup_ids: &[(usize, bool)],
 ) -> Result<String, Error> {
     use pg::visit::{EdgeRef, NodeRef};
 
@@ -97,16 +97,23 @@ pub(crate) fn create_graph(
 
     let mut node_stack = Vec::with_capacity(dup_ids.len());
 
-    let duplicates: Vec<_> = dup_ids.iter().map(|di| krates[*di].id.clone()).collect();
+    let duplicates: Vec<_> = dup_ids
+        .iter()
+        .filter_map(|(di, skipped)| (!*skipped).then_some(krates[*di].id.clone()))
+        .collect();
 
-    for (index, dupid) in dup_ids.iter().zip(duplicates.iter()) {
+    for (index, dupid) in dup_ids
+        .iter()
+        .filter_map(|(index, skipped)| (!*skipped).then_some(*index))
+        .zip(duplicates.iter())
+    {
         let dn = DupNode {
             kid: dupid,
             feature: None,
         };
         let nid = graph.add_node(dn);
         node_map.insert(dn, nid);
-        node_stack.push((krates::NodeId::new(*index), nid));
+        node_stack.push((krates::NodeId::new(index), nid));
     }
 
     {
diff --git a/src/snapshots/cargo_deny__diag__test__codes_unique.snap b/src/snapshots/cargo_deny__diag__test__codes_unique.snap
index ec0cc7fb..9f1bf64b 100644
--- a/src/snapshots/cargo_deny__diag__test__codes_unique.snap
+++ b/src/snapshots/cargo_deny__diag__test__codes_unique.snap
@@ -1,6 +1,7 @@
 ---
 source: src/diag.rs
 expression: unique
+snapshot_kind: text
 ---
 {
     "accepted",
@@ -52,6 +53,7 @@ expression: unique
     "unmatched-skip-root",
     "unmatched-source",
     "unmatched-wrapper",
+    "unnecessary-skip",
     "unresolved-workspace-dependency",
     "unsound",
     "unused-workspace-dependency",
diff --git a/tests/bans.rs b/tests/bans.rs
index b8d9d762..e8115bd8 100644
--- a/tests/bans.rs
+++ b/tests/bans.rs
@@ -327,3 +327,30 @@ unused = 'warn'
 
     insta::assert_json_snapshot!(diags);
 }
+
+/// Ensures skips generate warnings if they aren't needed
+#[test]
+fn unused_skips_generate_warnings() {
+    let diags = gather_bans(
+        func_name!(),
+        KrateGather {
+            name: "workspace",
+            no_default_features: true,
+            targets: &["x86_64-unknown-linux-gnu", "x86_64-pc-windows-msvc"],
+            ..Default::default()
+        },
+        r#"
+multiple-versions = 'deny'
+skip = [
+    # This actually has 3 versions, skip the two lower ones
+    'spdx:<0.10.0',
+    # This crate, but not exact version, is in the graph
+    'smallvec@1.0.0',
+    # This crate is in the graph, but there is only one version
+    'serde_json',
+]
+"#,
+    );
+
+    insta::assert_json_snapshot!(diags);
+}
diff --git a/tests/snapshots/bans__unused_skips_generate_warnings.snap b/tests/snapshots/bans__unused_skips_generate_warnings.snap
new file mode 100644
index 00000000..b9bc8a56
--- /dev/null
+++ b/tests/snapshots/bans__unused_skips_generate_warnings.snap
@@ -0,0 +1,241 @@
+---
+source: tests/bans.rs
+expression: diags
+snapshot_kind: text
+---
+[
+  {
+    "fields": {
+      "code": "skipped",
+      "graphs": [
+        {
+          "Krate": {
+            "name": "serde_json",
+            "version": "1.0.118"
+          },
+          "parents": [
+            {
+              "Krate": {
+                "name": "cargo_metadata",
+                "version": "0.18.1"
+              },
+              "parents": [
+                {
+                  "Krate": {
+                    "name": "krates",
+                    "version": "0.16.6"
+                  },
+                  "parents": [
+                    {
+                      "Krate": {
+                        "name": "wildcards-test-allow-git",
+                        "version": "0.1.0"
+                      },
+                      "parents": [
+                        {
+                          "Krate": {
+                            "name": "member-one",
+                            "version": "0.1.0"
+                          },
+                          "parents": [
+                            {
+                              "Krate": {
+                                "kind": "build",
+                                "name": "member-two",
+                                "version": "0.1.0"
+                              },
+                              "parents": [
+                                {
+                                  "Krate": {
+                                    "name": "root",
+                                    "version": "0.1.0"
+                                  }
+                                }
+                              ]
+                            },
+                            {
+                              "Krate": {
+                                "name": "root",
+                                "version": "0.1.0"
+                              },
+                              "repeat": true
+                            }
+                          ]
+                        },
+                        {
+                          "Krate": {
+                            "kind": "build",
+                            "name": "member-two",
+                            "version": "0.1.0"
+                          },
+                          "repeat": true
+                        }
+                      ]
+                    }
+                  ]
+                }
+              ]
+            }
+          ]
+        }
+      ],
+      "labels": [
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+  }
+]