Replace the null-terminated C-style strings in Value with hybrid C /
Pascal strings, where the length is stored in the allocation before the
data, and there is still a null byte at the end for the sake of C
interopt.
Co-Authored-By: Taeer Bar-Yam <taeer@bar-yam.me>
Co-Authored-By: Sergei Zimmerman <sergei@zimmerman.foo>
These steps are done (originally in order, but I squashed it as the end
result is still pretty small, and the churn in the code comments was a
bit annoying to keep straight).
1. Create proper struct type for string contexts on the heap
This will make it easier to change this type in the future.
2. Make `Value::StringWithContext` iterable
This make some for loops a lot more terse.
3. Encapsulate `Value::StringWithContext::Context::elems`
It turns out the iterators we just exposed are sufficient.
4. Make `StringWithContext::Context` length-prefixed instead
Rather than having a null pointer at the end, have a `size_t` at the
beginning. This is the exact same size (note that null pointer is
longer than null byte) and thus takes no more space!
Also, see the new TODO on naming. The thing we already so-named is a
builder type for string contexts, not the on-heap type. The
`fromBuilder` static method reflects what the names ought to be too.
Co-authored-by: Sergei Zimmerman <sergei@zimmerman.foo>
Otherwise PosTable grows indefinitely for each reload. Since
the total input size is limited to 4GB (uint32_t for byte offset PosIdx)
it can get exhausted pretty. This ensures that we don't waste memory
on reloads as well.
Update all channel URLs from https://nixos.org/channels/ to
https://channels.nixos.org/ to use the more reliable subdomain.
The nixos.org domain apex lacks IPv6 support due to DNS hoster
limitations. Using the subdomain allows better CDN distribution
and improved reliability.
Updated files:
- Installation scripts (multi-user and tarball installers)
- Channel URL resolution in eval-settings.cc
- Documentation and examples
- Docker image default channel URL
- Release notes (added note about URL change)
Fixes#14517
`allowedReferences` and friends can, in addition to supporting store
paths (and placeholders, but because those will be rewritten to store
paths), they also support to refering to other outputs in the derivation
by name.
We update the tests in order to cover for that.
(While we are at it, also introduce some scratch variables for paths and
placeholders to make the C++ literalsf for this test more concise.)
We now have functional tests for these. The unit tests added negligible
value while imposing a much higher maintenance cost.
The maintenance cost is high:
- No automatic accept option
- They broke 5+ times during this session due to implementation changes (trace count, ordering)
- They require understanding ANSI escape codes, Uncolored() wrappers, trace reversal
- They test empty traces HintFmt("") from withTrace(pos, "") - pure implementation detail
- They're fragile: adding any trace anywhere breaks the exact count assertions
The additional value over functional tests is minimal:
- Functional tests already verify the error message
- Functional tests already show trace order and content (as users see it, helps review)
- Unit tests verify "exactly 3 traces, not 2 or 4" - but users don't count traces
- Unit tests verify empty traces exist - but users never see them
The white-box testing catches the wrong things:
- It catches "you added helpful context" as a failure
- It doesn't catch "the context is confusing" (which functional tests would show)
- It enforces implementation details that should be allowed to evolve
Show which element(s) are involved at each error point:
- When an element is missing the "key" attribute, show the element
- When an element is not an attribute set, show the element
- When comparing keys fails, show both elements being compared
- When calling operator fails, show which element was being processed
This provides concrete context using ValuePrinter with errorPrintOptions.
Note: errorPrintOptions uses maxDepth=10 by default, which may print
quite deeply nested structures in error messages. This could potentially
be overwhelming, but follows the existing default for error contexts.
The old string format is a holdover from the pre JSON days. It is not
friendly to users who need to get the information out of it.
Also introduce the sort of versioning we have for derivation for this
format too.
- Use canonical content address JSON format for floating content
addressed derivation outputs
This keeps it more consistent.
- Reorganize inputs into nested structure (`inputs.srcs` and
`inputs.drvs`)
This will allow for an easier to use, but less compact, alternative
where `srcs` is just a list of derived paths.
It also allows for other experiments for derivations with a different
input structure, as I suspect will be needed for secure build traces.
This was already dropped in `inputFromURL()`, but not in
`inputFromAttrs()`. Now it's done in `fixGitURL()`, which is used by
both.
In principle, `git+` shouldn't be used in the `url` attribute, since
we already know that it's a Git URL. But since it currently works, we
don't want to break it.
Fixes#14429.
Have one to that instead of one to `Derivation`. `DerivationBuilder`
doesn't need `inputDrvs`, so `BasicDerivation` suffices.
(In fact, it doesn't need `inputSrcs` either, but we don't yet hve a
type to exclude that.)
We were calling git with `--quiet` in order not to mess up Nix's
progress bar. However, `runProgram()` already suspends the progress
bar (since git may be interactive) so that's no longer an issue. So we
can just run with `--progress` instead.
Fix#14480
This method is not well-defined for arbitrary stores, which do not have
a notion of a "real path" -- it is only well-defined for local file
systems stores, which do have exactly that notion, and so it is moved to
that sub-interface instead.
Some call-sites had to be fixed up for this, but in all cases the
changes are positive. Using `getFSSourceAccessor` allows for more other
stores to work properly. `nix-channel` was straight-up wrong in the case
of redirected local stores. And the building logic with remote building
and a non-local store is also fixed, properly gating some deletions on
store type.
Co-authored-by: Robert Hensing <robert@roberthensing.nl>
The assumption that no unknown paths can be returned is incorrect. It
can happen if a derivation has outputs that are substitutable, but
that have references that cannot be substituted (i.e. an incomplete
closure in the binary cache). This can easily happen with
magic-nix-cache.
Previously, only shared memory segments were cleaned up.
This could lead to leaked message queues and semaphore sets when builds use System V IPC, exhausting kernel IPC limits over time.
This commit extends the cleanup to all three System V IPC types:
1. Shared memory segments
2. Message queues
3. Semaphores
Additionally, we stop removing IPC objects during iteration, as it could corrupt the kernel's iterator state and cause some objects to be skipped. The new implementation uses a two-pass approach where we list first and then remove them in a separate pass.
The IPC IDs are now extracted during iteration using actual system calls (shmget, msgget, semget) rather than being looked up later, ensuring the objects exist when we capture their IDs.
