rust-lang/cargo · error

checksum for ` ` was not previously calculated, but a…

Error message

checksum for `{}` was not previously calculated, but a checksum could now be calculated

this could be indicative of a few possible situations:

    * the source `{}` did not previously support checksums,
      but was replaced with one that does
    * newer Cargo implementations know how to checksum this source, but this older implementation does not
    * the lock file is corrupt

What it means

Error "checksum for `{}` was not previously calculated, but a checksum could now be calculated this could be indicative of a few possible situations: * the source `{}` did not previously support checksums, but was replaced with one that does * newer Cargo implementations know how to checksum this source, but this older implementation does not * the lock file is corrupt " thrown in rust-lang/cargo.

When it happens

Trigger: Thrown at src/resolver/resolve.rs:237 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of rust-lang/cargo@eb98b54bc9 (2026-08-11). Data as JSON: /api/errors/95c3e851e91f7d81. Report an issue: GitHub.

Appendix: source

Thrown at src/resolver/resolve.rs:237

        // * A replacement source wasn't actually a replacement, some changes
        //   were made
        //
        // In all of these cases, we want to report an error to indicate that
        // something is awry. Normal execution (esp just using crates.io) should
        // never run into this.
        for (id, cksum) in previous.checksums.iter() {
            if let Some(mine) = self.checksums.get(id) {
                if mine == cksum {
                    continue;
                }

                // If the previous checksum wasn't calculated, the current
                // checksum is `Some`. This may indicate that a source was
                // erroneously replaced or was replaced with something that
                // desires stronger checksum guarantees than can be afforded
                // elsewhere.
                if cksum.is_none() {
                    anyhow::bail!(
                        "\
checksum for `{}` was not previously calculated, but a checksum could now \
be calculated

this could be indicative of a few possible situations:

    * the source `{}` did not previously support checksums,
      but was replaced with one that does
    * newer Cargo implementations know how to checksum this source, but this
      older implementation does not
    * the lock file is corrupt
",
                        id,
                        id.source_id()
                    )

                // If our checksum hasn't been calculated, then it could mean
                // that future Cargo figured out how to checksum something or

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