Commit graph

26 commits

Author SHA1 Message Date
John Ericson
60b7121d2c Make the Derived Path family of types inductive for dynamic derivations
We want to be able to write down `foo.drv^bar.drv^baz`:
`foo.drv^bar.drv` is the dynamic derivation (since it is itself a
derivation output, `bar.drv` from `foo.drv`).

To that end, we create `Single{Derivation,BuiltPath}` types, that are
very similar except instead of having multiple outputs (in a set or
map), they have a single one. This is for everything to the left of the
rightmost `^`.

`NixStringContextElem` has an analogous change, and now can reuse
`SingleDerivedPath` at the top level. In fact, if we ever get rid of
`DrvDeep`, `NixStringContextElem` could be replaced with
`SingleDerivedPath` entirely!

Important note: some JSON formats have changed.

We already can *produce* dynamic derivations, but we can't refer to them
directly. Today, we can merely express building or example at the top
imperatively over time by building `foo.drv^bar.drv`, and then with a
second nix invocation doing `<result-from-first>^baz`, but this is not
declarative. The ethos of Nix of being able to write down the full plan
everything you want to do, and then execute than plan with a single
command, and for that we need the new inductive form of these types.

Co-authored-by: Robert Hensing <roberth@users.noreply.github.com>
Co-authored-by: Valentin Gagarin <valentin.gagarin@tweag.io>
2023-08-10 00:08:32 -04:00
John Ericson
bc23a44c54 Make command infra less stateful and more regular
Already, we had classes like `BuiltPathsCommand` and `StorePathsCommand`
which provided alternative `run` virtual functions providing the
implementation with more arguments. This was a very nice and easy way to
make writing command; just fill in the virtual functions and it is
fairly clear what to do.

However, exception to this pattern were `Installable{,s}Command`. These
two classes instead just had a field where the installables would be
stored, and various side-effecting `prepare` and `load` machinery too
fill them in. Command would wish out those fields.

This isn't so clear to use.

What this commit does is make those command classes like the others,
with richer `run` functions.

Not only does this restore the pattern making commands easier to write,
it has a number of other benefits:

- `prepare` and `load` are gone entirely! One command just hands just
  hands off to the next.

- `useDefaultInstallables` because `defaultInstallables`. This takes
  over `prepare` for the one case that needs it, and provides enough
  flexiblity to handle `nix repl`'s idiosyncratic migration.

- We can use `ref` instead of `std::shared_ptr`. The former must be
  initialized (so it is like Rust's `Box` rather than `Option<Box>`,
  This expresses the invariant that the installable are in fact
  initialized much better.

  This is possible because since we just have local variables not
  fields, we can stop worrying about the not-yet-initialized case.

- Fewer lines of code! (Finally I have a large refactor that makes the
  number go down not up...)

- `nix repl` is now implemented in a clearer way.

The last item deserves further mention. `nix repl` is not like the other
installable commands because instead working from once-loaded
installables, it needs to be able to load them again and again.

To properly support this, we make a new superclass
`RawInstallablesCommand`. This class has the argument parsing and
completion logic, but does *not* hand off parsed installables but
instead just the raw string arguments.

This is exactly what `nix repl` needs, and allows us to instead of
having the logic awkwardly split between `prepare`,
`useDefaultInstallables,` and `load`, have everything right next to each
other. I think this will enable future simplifications of that argument
defaulting logic, but I am saving those for a future PR --- best to keep
code motion and more complicated boolean expression rewriting separate
steps.

The "diagnostic ignored `-Woverloaded-virtual`" pragma helps because C++
doesn't like our many `run` methods. In our case, we don't mind the
shadowing it all --- it is *intentional* that the derived class only
provides a `run` method, and doesn't call any of the overridden `run`
methods.

Helps with https://github.com/NixOS/rfcs/pull/134
2023-03-15 16:29:07 -04:00
Eelco Dolstra
b69a73a230 Get rid of some unchecked calls to std::cout 2023-03-02 15:02:24 +01:00
Eelco Dolstra
845fc3f605 Merge toDerivations() into toDerivedPaths()
toDerivedPaths() now returns DerivedPathWithInfo, which is DerivedPath
with some attributes needed by 'nix profile' etc.

Preparation for #7417.
2022-12-20 14:24:14 +01:00
John Ericson
678d1c2aa0 Factor out a LogStore interface
Continue progress on #5729.

Just as I hoped, this uncovered an issue: the daemon protocol is missing
a way to query build logs. This doesn't effect `unix://`, but does
effect `ssh://`. A FIXME is left for this, so we come back to it later.
2022-03-11 13:32:16 +00:00
John Ericson
242f9bf3dc std::visit by reference
I had started the trend of doing `std::visit` by value (because a type
error once mislead me into thinking that was the only form that
existed). While the optomizer in principle should be able to deal with
extra coppying or extra indirection once the lambdas inlined, sticking
with by reference is the conventional default. I hope this might even
improve performance.
2021-09-30 21:35:09 +00:00
regnat
2105084645 Enfore the use of properly built paths in libcmd
Replace `DerivedPathWithHints` by a new `BuiltPath` type that serves as
a proof that the corresponding path has been built.
2021-05-17 08:45:08 +02:00
regnat
ec613603ba DerivedPathWithHints -> BuiltPath
Just a renaming for now
2021-05-12 16:19:51 +02:00
John Ericson
179582872d Make DerivedPathWithHints a newtype
This allows us to namespace its constructors under it.
2021-04-05 10:05:21 -04:00
John Ericson
9b805d36ac Rename Buildable 2021-04-05 09:52:25 -04:00
Eelco Dolstra
58bacc85e7
Add 'nix log' manpage 2020-12-21 13:32:28 +01:00
Eelco Dolstra
85c8be6286 Remove static variable name clashes
This was useful for an experiment with building Nix as a single
compilation unit. It's not very useful otherwise but also doesn't
hurt...
2020-10-06 13:49:20 +02:00
John Ericson
e1de1fe0d8 Make Buildable a std::variant
I think this better captures the intent of what's going on: we either
have an opaque store path, or a drv path with some outputs.

Having this structure will also help us support CA derivations: we'll
have to allow the outpath paths to be optional, so the structure we gain
now makes up for the structure we loose then.
2020-07-23 19:02:57 +00:00
Eelco Dolstra
2d6d53bc87 nix: Fix examples 2020-07-15 20:28:16 +02:00
Eelco Dolstra
f132d82a79 nix --help: Group commands 2020-05-05 15:18:23 +02:00
Eelco Dolstra
bbe97dff8b Make the Store API more type-safe
Most functions now take a StorePath argument rather than a Path (which
is just an alias for std::string). The StorePath constructor ensures
that the path is syntactically correct (i.e. it looks like
<store-dir>/<base32-hash>-<name>). Similarly, functions like
buildPaths() now take a StorePathWithOutputs, rather than abusing Path
by adding a '!<outputs>' suffix.

Note that the StorePath type is implemented in Rust. This involves
some hackery to allow Rust values to be used directly in C++, via a
helper type whose destructor calls the Rust type's drop()
function. The main issue is the dynamic nature of C++ move semantics:
after we have moved a Rust value, we should not call the drop function
on the original value. So when we move a value, we set the original
value to bitwise zero, and the destructor only calls drop() if the
value is not bitwise zero. This should be sufficient for most types.

Also lots of minor cleanups to the C++ API to make it more modern
(e.g. using std::optional and std::string_view in some places).
2019-12-10 22:06:05 +01:00
Eelco Dolstra
ac67685606 Make subcommand construction in MultiCommand lazy
(cherry picked from commit a0de58f471)
2019-12-05 20:19:26 +01:00
Will Dietz
6454ca393a nix log: use pager 2018-01-12 15:05:26 -06:00
Eelco Dolstra
2ebeffcfd4 nix log: Add examples 2017-09-07 20:18:29 +02:00
Eelco Dolstra
df4342bc17
nix build: Create result symlinks 2017-09-06 16:03:22 +02:00
Eelco Dolstra
e9c07a3b26
nix edit / log: Operate on a single Installable 2017-08-29 16:18:00 +02:00
Jörg Thalheim
2fd8f8bb99 Replace Unicode quotes in user-facing strings by ASCII
Relevant RFC: NixOS/rfcs#4

$ ag -l | xargs sed -i -e "/\"/s/’/'/g;/\"/s/‘/'/g"
2017-07-30 12:32:45 +01:00
Eelco Dolstra
fdc9da034f
Avoid a call to derivationFromPath()
This doesn't work in read-only mode, ensuring that operations like

  nix path-info --store https://cache.nixos.org -S nixpkgs.hello

(asking for the closure size of nixpkgs.hello in cache.nixos.org) work
when nixpkgs.hello doesn't exist in the local store.
2017-07-14 18:29:10 +02:00
Eelco Dolstra
c769841bc4
Move code around 2017-04-25 12:07:31 +02:00
Eelco Dolstra
bcecc99007
Restructure installables handling in the "nix" command 2017-04-25 11:20:37 +02:00
Eelco Dolstra
5b86451f02
Add a "nix log" command
This replaces "nix-store --read-log". It checks the local store and
any configured substituters for the requested logs.
2017-03-15 16:48:29 +01:00