`--frozen` is not equivalent to specifying both `--locked` and `--offline`

[wegylexy]

Problem

This fails:

cargo install --path . --frozen

0.389   Installing myapp v0.1.0 (/app)
0.472     Updating crates.io index
0.493 error: attempting to make an HTTP request, but --frozen was specified

This works:

cargo install --path . --locked --offline

Steps

FROM rust:alpine AS deps
WORKDIR /app
RUN apk add --no-cache build-base openssl-dev
COPY Cargo.toml Cargo.lock ./
RUN mkdir src && \
    echo "fn main() {}" > src/main.rs && \
    cargo build --release && \
    rm -rf src

FROM deps AS build
COPY src src
RUN cargo install --path . --frozen

FROM alpine:latest AS publish
COPY --from=build /usr/local/cargo/bin/myapp /usr/local/bin/
ENTRYPOINT [ "myapp" ]

docker build -t myapp .

Possible Solution(s)

Specify both --locked and --offline instead of --frozen.

Notes

Environment is Docker Desktop on WSL2

Version

cargo 1.85.0 (d73d2caf9 2024-12-31)
release: 1.85.0
commit-hash: d73d2caf9e41a39daf2a8d6ce60ec80bf354d2a7
commit-date: 2024-12-31
host: x86_64-unknown-linux-musl
libgit2: 1.8.1 (sys:0.19.0 vendored)
libcurl: 8.9.0-DEV (sys:0.4.74+curl-8.9.0 vendored ssl:OpenSSL/1.1.1w)
ssl: OpenSSL 1.1.1w  11 Sep 2023
os: Alpine Linux 3.21.3 [64-bit]

[epage]

Hmm, some places call offline() and frozen() directly while others call network_allowed. Similar for locked() and frozen() vs lock_update_allowed.

Sometimes, this is for more specific error messages,

• cargo/src/cargo/util/network/http.rs

  Lines 28 to 39 in 7ea222d

  	if gctx.frozen() {
  	bail!(
  	"attempting to make an HTTP request, but --frozen was \
  	specified"
  	)
  	}
  	if gctx.offline() {
  	bail!(
  	"attempting to make an HTTP request, but --offline was \
  	specified"
  	)
  	}

• https://github.com/rust-lang/cargo/blob/master/src/cargo/sources/git/utils.rs#L959 (though this is more oddly written)
• https://github.com/rust-lang/cargo/blob/master/src/cargo/ops/lockfile.rs#L54

Other places, we don't have them paired

• https://github.com/rust-lang/cargo/blob/master/src/cargo/sources/registry/index/mod.rs#L485
• https://github.com/rust-lang/cargo/blob/master/src/cargo/sources/git/source.rs#L302
• https://github.com/rust-lang/cargo/blob/master/src/cargo/sources/git/source.rs#L315
• https://github.com/rust-lang/cargo/blob/master/src/cargo/core/resolver/errors.rs#L396

[epage]

From my naive perspective, I would assume each of those calls should be updated for handling both --offline and --frozen. To ensure correctness going forward, I'd go so far as removing GlobalContext::{frozen, offline, locked} and instead have a GobalContext::{offline_flag, locked_flag} as the only time to differentiate seems like it should be when reporting errors.

That so many of these missed calls exists makes me wonder if something there is intentional and would be interested in hearing from someone with more background on when these were added for why they diverge.

[ehuss]

I would agree there is some messiness here due to evolution, I don't think it is intentional.

The network_allowed and lock_update_allowed methods were intended to try to abstract it a little to avoid "oh, we forget to check for flag X", but I think in practice it is still a bit messy since different places are checking different things. It's also an issue with error messages, since they often want to say which flag caused the problem, which is a leaky abstraction for those methods. If we got rid of the frozen method, it could be difficult to provide a good error message.

I suspect there is some way we can clean this up, though I'm not sure exactly how. It might be to audit the usages of the specific calls (like offline()) that Ed did above, and to switch those to network_allowed or lock_update_allowed as appropriate, and then make sure the error messages provide the correct hints. I don't know if there's some way to make that easier or less error-prone, though (maybe the offline/frozen/locked methods could be renamed or moved or abstracted so that it is clear they should only be used for error messages?).