Rustdoc failed to read column from disk: data consumer error: invalid type: null, expected type data at line 1 column 4

[TomFryersMidsummer]

Code

Unfortunately, I haven't been able to make a minimal enough example that I'm able to share it. As soon as I disable more than a few crates from our 26-crate workspace, the error disappears. But the error doesn't seem to be caused by one particular crate. Perhaps there's a race condition somewhere.

Reproduction Steps

$ cargo clean
$ cargo doc --lib --bins --document-private-items --no-deps -v

Expected Outcome

As it does in Rust 1.90, the documentation should build successfully.

Actual Output

In Rust 1.91 and nightly, we get the following error

error: couldn't generate documentation: failed to read column from disk: data consumer error: invalid type: null, expected type data at line 1 column 4
  |
  = note: failed to create or modify "/home/tom.fryers/Documents/RoofScan/target/doc/search.index/type/": failed to read column from disk: data consumer error: invalid type: null, expected type data at line 1 column 4

error: could not document `roof-scan-outputs`

Caused by:
  process didn't exit successfully: `/home/tom.fryers/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/bin/rustdoc --edition=2024 --crate-type bin --crate-name roof_scan_outputs roof-scan-outputs/src/main.rs -o /home/tom.fryers/Documents/RoofScan/target/doc --check-cfg 'cfg(docsrs,test)' --check-cfg 'cfg(feature, values())' --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --diagnostic-width=189 -C metadata=008339708dcc1598 -L dependency=/home/tom.fryers/Documents/RoofScan/target/debug/deps --extern anyhow=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libanyhow-43f604131c3deeb1.rmeta --extern geometry=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libgeometry-e41688c6b10180bc.rmeta --extern image_formats=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libimage_formats-152134f144eec2e6.rmeta --extern itertools=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libitertools-1506c49be038510b.rmeta --extern ndarray=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libndarray-71260cca80a8dd7d.rmeta --extern ndarray_ref=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libndarray_ref-067f7da2c123772a.rmeta --extern roof_scan=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libroof_scan-f34847f14222ffa9.rmeta --extern svg=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libsvg-748dacaae780ef9e.rmeta --extern tiff=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libtiff-baf0150f618f86e8.rmeta --document-private-items '-Arustdoc::private-intra-doc-links' --crate-version 0.1.0` (exit status: 1)
warning: build failed, waiting for other jobs to finish...
error: could not document `land-registry`

Caused by:
  process didn't exit successfully: `/home/tom.fryers/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/bin/rustdoc --edition=2024 --crate-type lib --crate-name land_registry land-registry/src/lib.rs -o /home/tom.fryers/Documents/RoofScan/target/doc --check-cfg 'cfg(docsrs,test)' --check-cfg 'cfg(feature, values())' --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --diagnostic-width=189 -C metadata=b73d6a859571e856 -L dependency=/home/tom.fryers/Documents/RoofScan/target/debug/deps --extern bng=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libbng-d051a7d49fc0fefa.rmeta --extern geog=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libgeog-efff9649d43ec793.rmeta --extern itertools=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libitertools-1506c49be038510b.rmeta --extern thiserror=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libthiserror-025dc7ab1f8be558.rmeta --document-private-items --crate-version 0.1.0` (exit status: 1)
error: could not document `easy-pv-formats`

Caused by:
  process didn't exit successfully: `/home/tom.fryers/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/bin/rustdoc --edition=2024 --crate-type lib --crate-name easy_pv_formats easy-pv-formats/src/lib.rs -o /home/tom.fryers/Documents/RoofScan/target/doc --check-cfg 'cfg(docsrs,test)' --check-cfg 'cfg(feature, values())' --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --diagnostic-width=189 -C metadata=1183a0536eaea95e -L dependency=/home/tom.fryers/Documents/RoofScan/target/debug/deps --extern geometry=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libgeometry-e41688c6b10180bc.rmeta --extern more_itertools=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libmore_itertools-03833fe072e8477e.rmeta --extern ordered_float=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libordered_float-2271b971b6606687.rmeta --extern roof_scan=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libroof_scan-f34847f14222ffa9.rmeta --extern serde=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libserde-d4aa019a4fdd5da6.rmeta --extern spacelines=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libspacelines-9950595a3cecec29.rmeta --document-private-items --crate-version 0.1.0` (exit status: 1)
error: could not document `roof-scan`

Caused by:
  process didn't exit successfully: `/home/tom.fryers/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/bin/rustdoc --edition=2024 --crate-type bin --crate-name bench roof-scan/src/bin/bench.rs -o /home/tom.fryers/Documents/RoofScan/target/doc --check-cfg 'cfg(docsrs,test)' --check-cfg 'cfg(feature, values())' --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --diagnostic-width=189 -C metadata=7811f9570c7c40de -L dependency=/home/tom.fryers/Documents/RoofScan/target/debug/deps --extern arrayvec=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libarrayvec-c522d04ba0d149d2.rmeta --extern enum_dispatch=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libenum_dispatch-797e46689284c252.so --extern geometry=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libgeometry-e41688c6b10180bc.rmeta --extern geotiff=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libgeotiff-f4b4f23df7e768fc.rmeta --extern graph=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libgraph-d8ac2406d4a9f31d.rmeta --extern itertools=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libitertools-1506c49be038510b.rmeta --extern more_itertools=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libmore_itertools-03833fe072e8477e.rmeta --extern ndarray=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libndarray-71260cca80a8dd7d.rmeta --extern ndarray_ref=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libndarray_ref-067f7da2c123772a.rmeta --extern nonmax=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libnonmax-7b8f70987e1b2fed.rmeta --extern num_traits=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libnum_traits-05c940bc0b327bd7.rmeta --extern obstructions=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libobstructions-74acae3a5fb001e9.rmeta --extern ordered_float=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libordered_float-2271b971b6606687.rmeta --extern palette=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libpalette-9b1e68ffb918f14e.rmeta --extern pga=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libpga-d0bae3dafacd5cfc.rmeta --extern roof_scan=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libroof_scan-f34847f14222ffa9.rmeta --extern spacelines=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libspacelines-9950595a3cecec29.rmeta --extern statistics=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libstatistics-c44025af405fa9f1.rmeta --extern subarray=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libsubarray-a124a14646ec24bf.rmeta --extern thin_vec=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libthin_vec-edd67360050ebd9f.rmeta --extern thiserror=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libthiserror-025dc7ab1f8be558.rmeta --extern tracing=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libtracing-619cfedf92012744.rmeta --extern util=/home/tom.fryers/Documents/RoofScan/target/debug/deps/libutil-8e5baca9d1d64551.rmeta --document-private-items '-Arustdoc::private-intra-doc-links' --crate-version 0.1.0` (exit status: 1)

At the mentioned path:

$ ls target/doc/search.index/type/
5092402c3bd7.js

Version

Happens in both

rustc 1.91.0 (f8297e351 2025-10-28)
binary: rustc
commit-hash: f8297e351a40c1439a467bbbb6879088047f50b3
commit-date: 2025-10-28
host: x86_64-unknown-linux-gnu
release: 1.91.0
LLVM version: 21.1.2

and

rustc 1.93.0-nightly (b15a874aa 2025-11-02)
binary: rustc
commit-hash: b15a874aafe7eab9ea3ac2c1d59c7b03e1425027
commit-date: 2025-11-02
host: x86_64-unknown-linux-gnu
release: 1.93.0-nightly
LLVM version: 21.1.3

but Rust 1.90 was OK.

[fmease]

@notriddle, do you happen to have a clue how this might have come about even without a repro?