[meta] Reducing the number of dependencies

[Hywan]

Medusa (Bernini)

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Hello,

This project has too many dependencies according to me.

The number of dependencies (regardless of their versions, features etc.)

$ cargo tree --all-features --edges all --prefix none | rg -v '^$' | cut -d' ' -f 1 | sort | uniq | wc -l
539

This is a meta issue aiming at reducing the number of dependencies, thus reducing the compile-time, and the resulting binary size.

Removing duplicated dependencies

We have 35 duplicated dependencies:

$ cargo tree --all-features --duplicates | rg '^[a-z]' | datamash -W groupby 1 collapse 2 | tr '\t,' ' ' | sed -E -e 's/^([a-z0-9_\-]+)/* [ ] `\1`:/' | sed -E -e 's/(v.*) v/\1, v/g' | sed -E -e 's/v([0-9]+)/\1/g'

• bitflags: 2.10.0, 2.10.0
• camino: 1.2.1, 1.2.1
• crypto-common: 0.1.6, 0.1.6
• darling: 0.20.10, 0.21.1
• darling_core: 0.20.10, 0.21.1
• darling_macro: 0.20.10, 0.21.1
• derive_more: 1.0.0, 2.0.1
• derive_more-impl: 1.0.0, 2.0.1
• digest: 0.10.7, 0.10.7
• getrandom: 0.2.15, 0.3.1
• hashbrown: 0.14.5, 0.15.2, 0.16.1
• indexmap: 2.12.1, 2.12.1
• itertools: 0.10.5, 0.13.0, 0.14.0
• js_int: 0.2.2, 0.2.2
• libc: 0.2.175, 0.2.175
• phf: 0.11.2, 0.13.1
• phf_shared: 0.11.2, 0.13.1
• rand: 0.8.5, 0.8.5
• rand_core: 0.6.4, 0.6.4, 0.9.3
• ruma-identifiers-validation: 0.12.0, 0.12.0
• rustix: 0.38.41, 1.0.8
• semver: 1.0.27, 1.0.27
• serde: 1.0.228, 1.0.228
• serde_core: 1.0.228, 1.0.228
• sha2: 0.10.9, 0.10.9
• siphasher: 0.3.11, 1.0.1
• strum: 0.26.3, 0.27.2
• strum_macros: 0.26.4, 0.27.1
• syn: 1.0.109, 2.0.101
• thiserror: 1.0.63, 2.0.17
• thiserror-impl: 1.0.63, 2.0.17
• toml_datetime: 0.6.8, 0.7.2
• unicode-width: 0.1.13, 0.2.0
• webpki-roots: 0.26.3, 1.0.2
• winnow: 0.6.20, 0.7.13

Reviewing dependencies

A list of things we should do:

• reviewing the features, see if default-features = false can be used to avoid pulling useless dependencies,
• find dependencies that do similar things, and pick a single one of them,
• find dependencies where a smaller one might exist,
• any other ideas?