Commit graph

1415 commits

Author SHA1 Message Date
Eelco Dolstra
bf89cd95a4
Merge pull request #6525 from J-Swift/feature/bash-prefix
Add `bash-prompt-prefix` option
2022-05-13 14:06:07 +02:00
Théophane Hufschmitt
b944b588fa
Merge pull request #6523 from ncfavier/stop-logger-legacy
Stop the logger properly in legacy commands
2022-05-11 16:53:57 +02:00
Naïm Favier
1461e6cdda
Stop the logger properly in legacy commands
Ensures the logger is stopped on exit in legacy commands. Without this,
when using `nix-build --log-format bar` and stopping nix with CTRL+C,
the bar is not cleared from the screen.
2022-05-11 12:58:45 +02:00
Eli Kogan-Wang
aefc6c4f41 Add priority for nix profile install 2022-05-11 12:16:35 +02:00
Jimmy Reichley
584475acf9
Add documentation for bash-prompt-prefix 2022-05-10 16:55:25 -04:00
Jimmy Reichley
2998527b18
Allow setting bash-prompt-prefix nix develop configuration 2022-05-10 16:53:22 -04:00
Eelco Dolstra
a9cbc2857f nix develop: Find bin/bash in the bashInteractive outputs 2022-05-10 16:43:41 +02:00
Eelco Dolstra
c98648bef0 Merge remote-tracking branch 'origin/master' into debug-exploratory-PR 2022-05-04 14:10:21 +02:00
Eelco Dolstra
a3c6c5b1c7 nix profile: Support overriding outputs 2022-05-03 15:00:34 +02:00
Eelco Dolstra
4a79cba511 Allow selecting derivation outputs using 'installable!outputs'
E.g. 'nixpkgs#glibc^dev,static' or 'nixpkgs#glibc^*'.
2022-05-03 13:43:52 +02:00
Eelco Dolstra
404c222444
Merge pull request #6426 from edolstra/respect-outputs-to-install
nix: Respect meta.outputsToInstall, and use all outputs by default
2022-05-03 13:43:22 +02:00
Kjetil Orbekk
c21afd684c Update nix flake documentation of ref handling
Update the documentation about how `ref` is resolved if it is not
specified.

Add a note about special handling of local workdirs with `git+file`.
2022-04-29 18:46:21 -04:00
Ben Burdette
6e19947993 Merge branch 'master' into debug-merge-master 2022-04-28 12:32:57 -06:00
Eelco Dolstra
d77d813017 Shut up clang warning 2022-04-28 14:24:17 +02:00
Eelco Dolstra
13d8400ac5 Remove obsolete FIXME 2022-04-26 17:17:27 +02:00
Eelco Dolstra
1ddabe1a01 nix: Respect meta.outputsToInstall, and use all outputs by default
'nix profile install' will now install all outputs listed in the
package's meta.outputsToInstall attribute, or all outputs if that
attribute doesn't exist. This makes it behave consistently with
nix-env. Fixes #6385.

Furthermore, for consistency, all other 'nix' commands do this as
well. E.g. 'nix build' will build and symlink the outputs in
meta.outputsToInstall, defaulting to all outputs. Previously, it only
built/symlinked the first output. Note that this means that selecting
a specific output using attrpath selection (e.g. 'nix build
nixpkgs#libxml2.dev') no longer works. A subsequent PR will add a way
to specify the desired outputs explicitly.
2022-04-26 17:17:27 +02:00
Eelco Dolstra
474695975d EvalCache: Revert to using symbols in getAttr() 2022-04-26 14:01:42 +02:00
pennae
a385e51a08 rename SymbolIdx -> Symbol, Symbol -> SymbolStr
after #6218 `Symbol` no longer confers a uniqueness invariant on the
string it wraps, it is now possible to create multiple symbols that
compare equal but whose string contents have different addresses. this
guarantee is now only provided by `SymbolIdx`, leaving `Symbol` only as
a string wrapper that knows about the intricacies of how symbols need to
be formatted for output.

this change renames `SymbolIdx` to `Symbol` to restore the previous
semantics of `Symbol` to that name. we also keep the wrapper type and
rename it to `SymbolStr` instead of returning plain strings from lookups
into the symbol table because symbols are formatted for output in many
places. theoretically we do not need `SymbolStr`, only a function that
formats a string for output as a symbol, but having to wrap every symbol
that appears in a message into eg `formatSymbol()` is error-prone and
inconvient.
2022-04-25 15:37:01 +02:00
Théophane Hufschmitt
be28603dca Merge remote-tracking branch 'origin/master' into nixbuildaddprintstorepaths 2022-04-22 11:11:01 +02:00
pennae
8775be3393 store Symbols in a table as well, like positions
this slightly increases the amount of memory used for any given symbol, but this
increase is more than made up for if the symbol is referenced more than once in
the EvalState that holds it. on average every symbol should be referenced at
least twice (once to introduce a binding, once to use it), so we expect no
increase in memory on average.

symbol tables are limited to 2³² entries like position tables, and similar
arguments apply to why overflow is not likely: 2³² symbols would require as many
string instances (at 24 bytes each) and map entries (at 24 bytes or more each,
assuming that the map holds on average at most one item per bucket as the docs
say). a full symbol table would require at least 192GB of memory just for
symbols, which is well out of reach. (an ofborg eval of nixpks today creates
less than a million symbols!)
2022-04-21 21:56:31 +02:00
pennae
6526d1676b replace most Pos objects/ptrs with indexes into a position table
Pos objects are somewhat wasteful as they duplicate the origin file name and
input type for each object. on files that produce more than one Pos when parsed
this a sizeable waste of memory (one pointer per Pos). the same goes for
ptr<Pos> on 64 bit machines: parsing enough source to require 8 bytes to locate
a position would need at least 8GB of input and 64GB of expression memory. it's
not likely that we'll hit that any time soon, so we can use a uint32_t index to
locate positions instead.
2022-04-21 21:46:06 +02:00
pennae
39df15fb8e don't use full Pos for findPackageFilename/editorFor
only file and line of the returned position were ever used, it wasn't actually
used a position. as such we may as well use a path+int pair for only those two
values and remove a use of Pos that would not work well with a position table.
2022-04-21 21:25:18 +02:00
pennae
38de79fcf7 remove Bindings::need
a future commit will remove the ability to convert the symbol type used in
bindings to strings. since we only have two users we can inline the error check.
2022-04-21 21:25:18 +02:00
Eelco Dolstra
f05e1f6fbb Move hiliteMatches into a separate header
This is mostly so that we don't #include <regex> everywhere (which
adds quite a bit of compilation time).
2022-04-21 12:06:29 +02:00
Théophane Hufschmitt
9345b4e9ca
Merge pull request #3720 from obsidiansystems/fix-url-format
Avoid `fmt` when constructor already does it
2022-04-20 20:01:37 +02:00
John Ericson
3c220442ff Merge remote-tracking branch 'upstream/master' into fix-url-format 2022-04-20 16:53:16 +00:00
Artturin
51cfea8bb0 nix build: add --print-out-paths flag
has the same functionality as default nix-build

$ nix-build . -A "bash" -A "bash.dev" -A "tinycc"
/nix/store/4nmqxajzaf60yjribkgvj5j54x9yvr1r-bash-5.1-p12
/nix/store/c49i1ggnr5cc8gxmk9xm0cn961z104dn-bash-5.1-p12-dev
/nix/store/dbapb08862ajgaax3621fz8hly9fdah3-tcc-0.9.27+date=2022-01-11

$ nix-build . -A "bash"
/nix/store/4nmqxajzaf60yjribkgvj5j54x9yvr1r-bash-5.1-p12

$ $HOME/nixgits/nix/result/bin/nix build "nixpkgs#bash" "nixpkgs#bash.dev" "nixpkgs#tinycc" --print-out-paths
/nix/store/4nmqxajzaf60yjribkgvj5j54x9yvr1r-bash-5.1-p12
/nix/store/c49i1ggnr5cc8gxmk9xm0cn961z104dn-bash-5.1-p12-dev
/nix/store/dbapb08862ajgaax3621fz8hly9fdah3-tcc-0.9.27+date=2022-01-11

$ $HOME/nixgits/nix/result/bin/nix build "nixpkgs#bash" --print-out-paths
/nix/store/4nmqxajzaf60yjribkgvj5j54x9yvr1r-bash-5.1-p12
2022-04-20 19:35:46 +03:00
ckie
0e2b01b14e
nix repl: make symlinks with the :bl command
Requested by ppepino on the Matrix:
https://matrix.to/#/!KqkRjyTEzAGRiZFBYT:nixos.org/$Tb32BS3rVE2BSULAX4sPm0h6CDewX2hClOTGzTC7gwM?via=nixos.org&via=matrix.org&via=nixos.dev

This adds a new command, :bl, which works like :b but also creates
a GC root symlink to the various derivation outputs.

ckie@cookiemonster ~/git/nix -> ./outputs/out/bin/nix repl
Welcome to Nix 2.6.0. Type :? for help.

nix-repl> :l <nixpkgs>
Added 16118 variables.

nix-repl> :b runCommand "hello" {} "echo hi > $out"

This derivation produced the following outputs:
  ./repl-result-out -> /nix/store/kidqq2acdpi05c4a9mlbg2baikmzik44-hello
[1 built, 0.0 MiB DL]
ckie@cookiemonster ~/git/nix -> cat ./repl-result-out
hi
2022-04-20 00:20:29 +03:00
Eelco Dolstra
c9e58aa5ff Require formatters to be packages
Because of 9b41239d8f, a formatter can
no longer be a package *or* an app. So let's require it to be a
package for now.
2022-04-19 20:48:13 +02:00
Eelco Dolstra
48a467f2b9 Merge branch 'issue-6075' of https://github.com/kamadorueda/nix 2022-04-19 20:21:32 +02:00
Eelco Dolstra
2016b7142a Fix compilation, style fixes 2022-04-19 13:41:32 +02:00
Eelco Dolstra
b529a41814 Merge branch 'make-flake-show-more-lenient-on-apps' of https://github.com/flox/nix 2022-04-19 13:41:24 +02:00
Eelco Dolstra
018db1c420
Merge pull request #6404 from edolstra/unify-flake-attr-eval
Make InstallableFlake::toValue() and toDerivation() behave consistently
2022-04-19 11:53:27 +02:00
John Ericson
75b62e5260 Avoid fmt when constructor already does it
There is a correctnes issue here, but #3724 will fix that. This is just
a cleanup for brevity's sake.
2022-04-19 01:44:11 +00:00
Robert Helgesson
8b659eacce
Add .tgz as tarball extension in documentation
Support for the `tgz` shorthand was added in
52f5fa948a.
2022-04-18 17:14:15 +02:00
Ben Burdette
93b8d31508 Merge branch 'master' into debug-exploratory-PR 2022-04-15 14:49:08 -06:00
Eelco Dolstra
b135de2b5f
Merge pull request #6323 from erikarvstedt/eval-read-only
`nix eval`: Add option `--read-only`
2022-04-15 10:31:05 +02:00
Tom Bereknyei
9b41239d8f fix: ensure apps are apps and packages are packages 2022-04-14 23:57:52 -04:00
Eelco Dolstra
d89840b103 Make InstallableFlake::toValue() and toDerivation() behave consistently
In particular, this means that 'nix eval` (which uses toValue()) no
longer auto-calls functions or functors (because
AttrCursor::findAlongAttrPath() doesn't).

Fixes #6152.

Also use ref<> in a few places, and don't return attrpaths from
getCursor() because cursors already have a getAttrPath() method.
2022-04-14 14:07:04 +02:00
Ben Burdette
1a93ac8133 Merge remote-tracking branch 'upstream/master' into upstream-merge 2022-04-07 13:42:01 -06:00
Rehno Lindeque
b9c969a866 nix flake check: Warn about deprecated nixosModule output 2022-04-06 12:20:39 -04:00
Eelco Dolstra
27b952a8a1
Merge pull request #6362 from thufschmitt/verbose-doctor
doctor: Always show the output
2022-04-05 17:33:10 +02:00
Théophane Hufschmitt
9a640afc1e doctor: Always show the output
Fix https://github.com/NixOS/nix/issues/6342
2022-04-05 14:04:01 +02:00
Théophane Hufschmitt
5abe3f4aa6 Allow welcomeText when checking a flake template
Fix https://github.com/NixOS/nix/issues/6321
2022-04-05 11:03:43 +02:00
Tom Bereknyei
c1e2ce4515 fix(run): set applyNixConfig lockFlag 2022-04-01 23:41:34 -04:00
Eelco Dolstra
bf4895961d
Merge pull request #6344 from flox/profile_url_uri
profile!: consistent use of url/uri. create new version
2022-04-01 14:38:32 +02:00
Eelco Dolstra
5cd72598fe Add support for impure derivations
Impure derivations are derivations that can produce a different result
every time they're built. Example:

  stdenv.mkDerivation {
    name = "impure";
    __impure = true; # marks this derivation as impure
    outputHashAlgo = "sha256";
    outputHashMode = "recursive";
    buildCommand = "date > $out";
  };

Some important characteristics:

* This requires the 'impure-derivations' experimental feature.

* Impure derivations are not "cached". Thus, running "nix-build" on
  the example above multiple times will cause a rebuild every time.

* They are implemented similar to CA derivations, i.e. the output is
  moved to a content-addressed path in the store. The difference is
  that we don't register a realisation in the Nix database.

* Pure derivations are not allowed to depend on impure derivations. In
  the future fixed-output derivations will be allowed to depend on
  impure derivations, thus forming an "impurity barrier" in the
  dependency graph.

* When sandboxing is enabled, impure derivations can access the
  network in the same way as fixed-output derivations. In relaxed
  sandboxing mode, they can access the local filesystem.
2022-03-31 13:43:20 +02:00
Tom Bereknyei
50f9f335c9 profile!: consistent use of url/uri. create new version 2022-03-30 16:35:26 -04:00
Tom Bereknyei
d77823b502 bundler: update default bundler to support new bundler API 2022-03-30 16:10:42 -04:00
Théophane Hufschmitt
390269ed87 Simplify the handling of the hash modulo
Rather than having four different but very similar types of hashes, make
only one, with a tag indicating whether it corresponds to a regular of
deferred derivation.

This implies a slight logical change: The original Nix+multiple-outputs
model assumed only one hash-modulo per derivation. Adding
multiple-outputs CA derivations changed this as these have one
hash-modulo per output. This change is now treating each derivation as
having one hash modulo per output.
This obviously means that we internally loose the guaranty that
all the outputs of input-addressed derivations have the same hash
modulo. But it turns out that it doesn’t matter because there’s nothing
in the code taking advantage of that fact (and it probably shouldn’t
anyways).

The upside is that it is now much easier to work with these hashes, and
we can get rid of a lot of useless `std::visit{ overloaded`.

Co-authored-by: John Ericson <John.Ericson@Obsidian.Systems>
2022-03-29 18:17:35 +02:00
Théophane Hufschmitt
2d572a250f
Merge pull request #6330 from edolstra/run-remote-store
nix {run,shell}: Print a better error message if the store is not local
2022-03-28 17:57:37 +02:00
Eelco Dolstra
b266fd53dd nix {run,shell}: Print a better error message if the store is not local
Closes #6317
2022-03-28 14:58:38 +02:00
Eelco Dolstra
057f9ee190 nix profile install: Don't use queryDerivationOutputMap()
Instead get the outputs from Installable::build(). This will also
allow 'nix profile install' to support impure derivations.

Fixes #6286.
2022-03-28 14:23:39 +02:00
Erik Arvstedt
16860a0328 nix eval: Add option read-only 2022-03-26 11:32:38 +01:00
Eelco Dolstra
86b05ccd54 Only provide builtin.{getFlake,fetchClosure} is the corresponding experimental feature is enabled
This allows writing fallback code like

  if builtins ? fetchClosure then
    builtins.fetchClose { ... }
  else
    builtins.storePath ...
2022-03-25 14:04:18 +01:00
polykernel
cbcb69a39c nix: allow whitespace characters before command in repl
Before this change, processLine always uses the first character
as the start of the line. This cause whitespaces to matter at the
beginning of the line whereas it does not matter anywhere else.

This commit trims leading white spaces of the string line so that
subsequent operations can be performed on the string without explicitly
tracking starting and ending indices of the string.
2022-03-24 21:33:29 -04:00
Eelco Dolstra
e5f7029ba4 nix store make-content-addressed: Support --from / --to 2022-03-24 21:33:33 +01:00
Eelco Dolstra
5acaf13d35 Rename 'nix store make-content-addressable' to 'nix store make-content-addressed' 2022-03-24 21:33:33 +01:00
Eelco Dolstra
545c2d0d8c fetchClosure: Allow a path to be rewritten to CA on the fly
The advantage is that the resulting closure doesn't need to be signed,
so you don't need to configure any binary cache keys on the client.
2022-03-24 21:33:33 +01:00
Rok Garbas
4546a007a4
Fix flake profile use of originalUrl vs. originalUri
Fixes #5872
2022-03-24 12:28:38 +01:00
Hideaki Kawai
3b776cb0a7 nix edit: support kakoune 2022-03-22 23:18:02 +09:00
Eelco Dolstra
e4ff430866
Merge pull request #6237 from obsidiansystems/store-path-string-context
Decode string context straight to using StorePaths
2022-03-22 10:29:46 +01:00
John Ericson
4d6a3806d2 Decode string context straight to using StorePaths
I gather decoding happens on demand, so I hope don't think this should
have any perf implications one way or the other.
2022-03-18 15:36:11 +00:00
John Ericson
8496be7def Use Deferred when building an input-addressed drv
Easier than using dummy path with input addressed.
2022-03-18 14:59:56 +00:00
John Ericson
197feed51d Clean up DerivationOutput, and headers
1. `DerivationOutput` now as the `std::variant` as a base class. And the
   variants are given hierarchical names under `DerivationOutput`.

   In 8e0d0689be @matthewbauer and I
   didn't know a better idiom, and so we made it a field. But this sort
   of "newtype" is anoying for literals downstream.

   Since then we leaned the base class, inherit the constructors trick,
   e.g. used in `DerivedPath`. Switching to use that makes this more
   ergonomic, and consistent.

2. `store-api.hh` and `derivations.hh` are now independent.

   In bcde5456cc I swapped the dependency,
   but I now know it is better to just keep on using incomplete types as
   much as possible for faster compilation and good separation of
   concerns.
2022-03-17 22:35:53 +00:00
Théophane Hufschmitt
3fc4c612fb Fix nix build --dry-run with CA derivations
Don’t try and assume that we know the output paths when we’ve just built
with `--dry-run`. Instead make `--dry-run` follow a different code path
that won’t assume the knowledge of the output paths at all.

Fix #6275
2022-03-17 11:55:19 +01:00
Théophane Hufschmitt
516a7ac4de
Merge pull request #6229 from obsidiansystems/refactor-hash-modulo
Overhaul derivation hash modulo somewhat
2022-03-15 21:23:44 +01:00
John Ericson
0948b8e94d Reduce variants for derivation hash modulo
This changes was taken from dynamic derivation (#4628). It` somewhat
undoes the refactors I first did for floating CA derivations, as the
benefit of hindsight + requirements of dynamic derivations made me
reconsider some things.

They aren't to consequential, but I figured they might be good to land
first, before the more profound changes @thufschmitt has in the works.
2022-03-11 21:20:37 +00:00
Kevin Amado
2191dab657
nix-fmt: add command 2022-03-11 10:00:19 -05:00
John Ericson
a03b1fd7f6 Deduplicate the Store downcasting with a template 2022-03-11 13:32:33 +00:00
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
073e134de6 Rename requireGcStore to GcStore::require
I should have done this to begin with. This will be nicer once more
Store sub-interfaces exist too, to illustrate the pattern.
2022-03-11 13:27:38 +00:00
Eelco Dolstra
504e3b2a8f Style 2022-03-07 20:07:43 +01:00
Guillaume Desforges
436c6e900f Explicit error in flake init/new when not in store 2022-03-07 17:57:52 +01:00
John Ericson
6636202356 Factor out a GcStore interface
Starts progress on #5729.

The idea is that we should not have these default methods throwing
"unimplemented". This is a small step in that direction.

I kept `addTempRoot` because it is a no-op, rather than failure. Also,
as a practical matter, it is called all over the place, while doing
other tasks, so the downcasting would be annoying.

Maybe in the future I could move the "real" `addTempRoot` to `GcStore`,
and the existing usecases use a `tryAddTempRoot` wrapper to downcast or
do nothing, but I wasn't sure whether that was a good idea so with a
bias to less churn I didn't do it yet.
2022-03-03 19:01:25 +00:00
Eelco Dolstra
ecff9d969a printValue(): Don't show repeated values
Fixes #6157.
2022-03-03 13:18:23 +01:00
Eelco Dolstra
b55d79728c Add EvalState::coerceToStorePath() helper
This is useful whenever we want to evaluate something to a store path
(e.g. in get-drvs.cc).

Extracted from the lazy-trees branch (where we can require that a
store path must come from a store source tree accessor).
2022-03-02 23:58:58 +01:00
Eelco Dolstra
161f798aa1 nix profile: Support CA derivations 2022-03-02 20:38:51 +01:00
Eelco Dolstra
54888b92de Move installables-related operations 2022-03-02 19:19:51 +01:00
Eelco Dolstra
b39ef07414 Style 2022-03-02 11:46:15 +01:00
Théophane Hufschmitt
c2720797d5
Merge pull request #6072 from Ma27/fix-nix-why-depends-non-precise
nix/why-depends: fix output when not using `--precise`
2022-02-28 11:46:50 +01:00
Eelco Dolstra
df552ff53e Remove std::string alias (for real this time)
Also use std::string_view in a few more places.
2022-02-25 16:13:02 +01:00
Eelco Dolstra
59683733f5
Merge pull request #6089 from edolstra/dot-default
Replace defaultBla.$system with bla.$system.default
2022-02-24 21:16:58 +01:00
Eelco Dolstra
8518cebfce libfetchers: Rename immutable -> locked
This is more consistent with flake terminology.
2022-02-24 18:09:00 +01:00
Théophane Hufschmitt
6524eb4b77
Merge pull request #5342 from Misterio77/add-sourcehut
Add support for sourcehut input scheme
2022-02-24 09:09:21 +01:00
Eelco Dolstra
1a6548ca75 Update docs 2022-02-22 14:32:56 +01:00
Eelco Dolstra
d4428d00ae nix flake check: Warn about deprecated flake outputs 2022-02-22 14:19:39 +01:00
Eelco Dolstra
162fbe31ff Replace defaultBla.$system with bla.$system.default
This also simplifies some InstallableFlake logic and fixes 'nix
bundle' parsing its installable twice.

Fixes #5532.
2022-02-22 11:47:41 +01:00
Eelco Dolstra
caf5172945
Merge pull request #6136 from matthewbauer/profile-upgrade-verbosity
Add verbosity to nix profile upgrade
2022-02-21 22:30:47 +01:00
Matthew Bauer
3cd958849b
Apply suggestions from code review
Co-authored-by: Eelco Dolstra <edolstra@gmail.com>
2022-02-21 10:04:04 -06:00
Eelco Dolstra
fe9afb65bb Remove std::set alias 2022-02-21 16:28:23 +01:00
Matthew Bauer
61295b910f Add verbosity to nix profile upgrade
Followup of https://github.com/NixOS/nix/pull/6086. This time adding a
warning if no packages are upgraded.
2022-02-20 23:46:11 -06:00
Linus Heckemann
dbdc63bc41 path-info: use full store paths when we have them
Fixes #5645
2022-02-19 00:32:05 +01:00
Eelco Dolstra
a768e85e2f
Merge pull request #6103 from Radvendii/welcomeText
add descriptive output when creating templates
2022-02-17 21:06:10 +01:00
Taeer Bar-Yam
f56dd3a36b make flake template welcomeText markdown 2022-02-17 13:59:32 -05:00
Taeer Bar-Yam
f3a2940e70 add descriptive output when creating templates
this includes a `welcomeText` attribute which can be set in the
template, as well as outputing which files were created.
2022-02-15 11:50:14 -05:00
Gabriel Fontes
72e8f94081
add sourcehut input scheme 2022-02-14 23:53:01 -03:00
Eelco Dolstra
023e459777 InstallableFlake: Default attr paths cleanup
This removes some duplicated logic, and fixes "nix bundle" parsing its
installable twice.
2022-02-14 21:06:11 +01:00
Tom Bereknyei
270fb5f192 profile: add verbosity
warn if there are no matches and give notice of removing packages as
they are found
2022-02-11 10:44:33 -05:00
Maximilian Bosch
5b586575ac
nix/why-depends: fix output when not using --precise
On Nix 2.6 the output of `nix why-depends --all` seems to be somewhat
off:

    $ nix why-depends /nix/store/kn47hayxab8gc01jhr98dwyywbx561aq-nixos-system-roflmayr-21.11.20220207.6c202a9.drv /nix/store/srn5jbs1q30jpybdmxqrwskyny659qgc-nix-2.6.drv --derivation  --extra-experimental-features nix-command  --all
    /nix/store/kn47hayxab8gc01jhr98dwyywbx561aq-nixos-system-roflmayr-21.11.20220207.6c202a9.drv
        └───/nix/store/g8bpgfjhh5vxrdq0w6r6s64f9kkm9z6c-etc.drv
        │   └───/nix/store/hm0jmhp8shbf3cl846a685nv4f5cp3fy-nspawn-inst.drv
        | [...]
            └───/nix/store/2d6q3ygiim9ijl5d4h0qqx6vnjgxywyr-system-units.drv
                └───/nix/store/dil014y1b8qyjhhhf5fpaah5fzdf0bzs-unit-systemd-nspawn-hydra.service.drv
                    └───/nix/store/a9r72wwx8qrxyp7hjydyg0gsrwnn26zb-activate.drv
                        └───/nix/store/99hlc7i4gl77wq087lbhag4hkf3kvssj-nixos-system-hydra-21.11pre-git.drv

Please note that `[...]-system-units.drv` is supposed to be a direct
child of `[...]-etc.drv`.

The reason for that is that each new level printed by `printNode` is
four spaces off in comparison to `nix why-depends --precise` because the
recursive `printNode()` only prints the path and not the `tree*`-chars in
the case of `--precise` and in this format the path is four spaces further
indented, i.e. on a newline, but on the same level as the path's children, i.e.

    /nix/store/kn47hayxab8gc01jhr98dwyywbx561aq-nixos-system-roflmayr-21.11.20220207.6c202a9.drv
    └───/: …1-p8.drv",["out"]),("/nix/store/g8bpgfjhh5vxrdq0w6r6s64f9kkm9z6c-etc.drv",["out"]),("/nix/store/…
        → /nix/store/g8bpgfjhh5vxrdq0w6r6s64f9kkm9z6c-etc.drv

As you can see `[...]-etc.drv` is a direct child of the root, but four
spaces indented. This logic was directly applied to the code-path with
`precise=false` which resulted in `tree*` being printed four spaces too
deep.

In case of no `--precise`, `hits[hash]` is empty and the path itself
should be printed rather than hits using the same logic as for `hits[hash]`.

With this fix, the output looks correct now:

    /nix/store/kn47hayxab8gc01jhr98dwyywbx561aq-nixos-system-roflmayr-21.11.20220207.6c202a9.drv
    └───/nix/store/g8bpgfjhh5vxrdq0w6r6s64f9kkm9z6c-etc.drv
        ├───/nix/store/hm0jmhp8shbf3cl846a685nv4f5cp3fy-nspawn-inst.drv
        | [...]
        └───/nix/store/2d6q3ygiim9ijl5d4h0qqx6vnjgxywyr-system-units.drv
            └───/nix/store/dil014y1b8qyjhhhf5fpaah5fzdf0bzs-unit-systemd-nspawn-hydra.service.drv
                └───/nix/store/a9r72wwx8qrxyp7hjydyg0gsrwnn26zb-activate.drv
                    └───/nix/store/99hlc7i4gl77wq087lbhag4hkf3kvssj-nixos-system-hydra-21.11pre-git.drv
2022-02-10 14:26:00 +01:00