Commit graph

2093 commits

Author SHA1 Message Date
Ben Burdette 59b1f5c701 Merge branch 'master' into errors-phase-2 2020-05-11 14:35:30 -06:00
Ben Burdette 958e81987b switch from printError warnings to logWarnings 2020-05-11 13:02:16 -06:00
Domen Kožar 5bdb67c843
Merge pull request #3568 from kolloch/outputHashModeError
libstore/build.cc: more explicit error about form of output
2020-05-11 18:14:32 +02:00
Domen Kožar 1d8144e36b
Update src/libstore/build.cc 2020-05-11 18:14:23 +02:00
Benjamin Hipple 146f9c114f doc: consistently refer to 'fixed-output' with a dash
General cleanup that makes it easier to search for the term.
2020-05-09 10:58:43 -04:00
Alexander Bantyev 772e5db828
Mention build users in the 'waiting for' message 2020-05-08 12:29:00 +03:00
Alexander Bantyev 14073fb76b
Don't block while waiting for build users 2020-05-08 12:22:39 +03:00
Ben Burdette e3901638b5 todo removal 2020-05-06 15:01:13 -06:00
Eelco Dolstra 74a1bfdcab
Merge pull request #3546 from guibou/nix_readfile_on_0_sized_files
builtins.readFile: do not truncate content
2020-05-06 11:33:55 +02:00
Peter Kolloch 9be46859a9 libstore/build.cc: more explicit about form of output
Be more explicit about why we expect a regular file as output
when outputHashMode=flat for a fixed output derivation.
2020-05-06 11:21:12 +02:00
Eelco Dolstra 02c5914ea4
Merge pull request #3562 from pikajude/master
Use fragment size for autoGC capacity calculation
2020-05-06 11:19:30 +02:00
Eelco Dolstra fd4911269f
Revert "Merge pull request #3558 from LnL7/ssh-ng-stderr"
This reverts commit 3ebfbecdd1, reversing
changes made to c089c52d5f.

https://github.com/NixOS/nix/pull/3558
2020-05-06 10:54:18 +02:00
Alexander Bantyev 04967dee9d
Wait for build users when none are available 2020-05-05 13:04:36 +03:00
Ben Burdette 7ffb5efdbc appending to hints; remove _printError 2020-05-04 16:19:57 -06:00
Jude Taylor e2fc575c61 nix auto-gc: use fragment size 2020-05-04 14:42:06 -07:00
Eelco Dolstra a721a0b114 Flag: Use designated initializers 2020-05-04 22:40:19 +02:00
Ben Burdette ab6f0b9641 convert some printError calls to logError 2020-05-03 08:01:25 -06:00
Daiderd Jordan f16e24f95e
remote-store: don't log raw stderr by default
For remote stores the log messages are already forwarded as structured
STDERR_RESULT messages so the old format is duplicate information.  But
still included with -vvv since it could be useful for debugging
problems.

    $ nix build -L /nix/store/nl71b2niws857ffiaggyrkjwgx9jjzc0-foo.drv --store ssh-ng://localhost
    Hello World!
    foo> Hello World!
    [1/0/1 built] building foo

Fixes #3556
2020-05-02 23:40:50 +02:00
Ben Burdette 4b99c09f5c convert some errors 2020-05-01 14:32:06 -06:00
Ben Burdette 39ff80d031 errorinfo constructor test 2020-04-29 18:57:05 -06:00
Guillaume Bouchard 7afcb5af98 Remove the drain argument from readFile
Now it is always `drain` (see previous commit).
2020-04-29 18:43:45 +02:00
Antoine Eiche ca93b26db6 Only call grantpt on MacOS systems
The commit 3cc1125595 adds a `grantpt`
call on the builder pseudo terminal fd. This call is actually only
required for MacOS, but it however requires a RW access to /dev/pts
which is only RO bindmounted in the Bazel Linux sandbox. So, Nix can
not be actually run in the Bazel Linux sandbox for unneeded reasons.
2020-04-29 15:43:20 +02:00
Ben Burdette 22e6490311 Error classname as name 2020-04-28 21:06:08 -06:00
Dustin DeWeese c0d940978a Replace select() with poll() to allow waiting on more than FD_SETSIZE fds 2020-04-21 16:21:28 -07:00
Ben Burdette e4fb9a3849 remove 'format' from Error constructor calls 2020-04-21 17:07:07 -06:00
Ben Burdette 15e9564fd1 logEI for tunnelLogger and progressbar 2020-04-19 17:16:51 -06:00
Ben Burdette 3d5b1032a1 logError, logWarning; Logger functions; switch to Verbosity enum 2020-04-17 15:07:44 -06:00
Eelco Dolstra a118293bd0
Merge pull request #3458 from zimbatm/nix-user-conf-dir
NIX_USER_CONF_FILES
2020-04-15 13:00:28 +02:00
Jonas Chevalier 895516cadf
add NIX_USER_CONF_FILES
Motivation: maintain project-level configuration files.

Document the whole situation a bit better so that it corresponds to the
implementation, and add NIX_USER_CONF_FILES that allows overriding
which user files Nix will load during startup.
2020-04-14 18:45:06 +02:00
Bruce Toll 8132d0a12e Fix nix-build --check -K in sandbox w/o root
Temporarily add user-write permission to build directory so that it
can be moved out of the sandbox to the store with a .check suffix.

This is necessary because the build directory has already had its
permissions set read-only, but write permission is required
to update the directory's parent link to move it out of the sandbox.

Updated the related --check "derivation may not be deterministic"
messages to consistently use the real store paths.

Added test for non-root sandbox nix-build --check -K to demonstrate
issue and help prevent regressions.
2020-04-10 16:23:10 -04:00
Domen Kožar db25a6d7bb
Merge pull request #2689 from tollb/fix/delete_tmp_dir_when_build_check_ok
Delete temporary directory on successful build
2020-04-10 09:47:57 +02:00
Bruce Toll 16a4864759 Delete temporary directory on successful build
With --check and the --keep-failed (-K) flag, the temporary directory
was being retained regardless of whether the build was successful and
reproducible.  This removes the temporary directory, as expected, on
a reproducible check build.

Added tests to verify that temporary build directories are not
retained unnecessarily, particularly when using --check with
--keep-failed.
2020-04-09 16:37:41 -04:00
Philipp Middendorf 04bedda0b6 gc.cc: Ignore hidden files in temproots 2020-04-09 17:05:29 +02:00
Nikola Knezevic f5095594e7 datatransfer.{cc,hh} -> filetransfer.{cc,hh} 2020-04-08 22:26:57 +02:00
Nikola Knezevic c330109bfa DataTransfer -> FileTransfer 2020-04-08 22:26:57 +02:00
Nikola Knezevic 7848372b0f Add upload method 2020-04-08 22:26:57 +02:00
Nikola Knezevic a0c5931208 actDownload -> actDataTransfer 2020-04-08 22:26:57 +02:00
Nikola Knezevic c4c1ae0a00 DownloadError -> DataTransferError 2020-04-08 22:26:57 +02:00
Nikola Knezevic 213d124277 DownloadItem -> TransferItem 2020-04-08 22:26:57 +02:00
Nikola Knezevic cd391206e6 {get,make,new}Downloader -> DataTransfer 2020-04-08 22:26:57 +02:00
Nikola Knezevic 2df2741ec6 enqueueDownload -> enqueueDataTransfer 2020-04-08 22:26:57 +02:00
Nikola Knezevic 142ed7fe45 DownloadResult -> DataTransferResult 2020-04-08 22:26:57 +02:00
Nikola Knezevic e5cc53beec DownloadSettings -> DataTransferSettings 2020-04-08 22:26:57 +02:00
Nikola Knezevic 741e9012d3 Rename src/lib/download.* to src/lib/datatransfer.* 2020-04-08 22:26:57 +02:00
Nikola Knezevic 65ef57e0cb DownloadRequest -> DataTransferRequest 2020-04-08 22:26:57 +02:00
Domen Kožar bf81b31559
build.cc: improve message if home directory exists 2020-04-08 18:27:10 +02:00
Eelco Dolstra 1ab8d6ac18
Downloader: Only write data to the sink on a 200 response
Hopefully fixes #3278.
2020-04-08 15:27:09 +02:00
Eelco Dolstra cd39709003 Cleanup 2020-04-07 09:27:17 +02:00
Eelco Dolstra 462421d345 Backport libfetchers from the flakes branch
This provides a pluggable mechanism for defining new fetchers. It adds
a builtin function 'fetchTree' that generalizes existing fetchers like
'fetchGit', 'fetchMercurial' and 'fetchTarball'. 'fetchTree' takes a
set of attributes, e.g.

  fetchTree {
    type = "git";
    url = "https://example.org/repo.git";
    ref = "some-branch";
    rev = "abcdef...";
  }

The existing fetchers are just wrappers around this. Note that the
input attributes to fetchTree are the same as flake input
specifications and flake lock file entries.

All fetchers share a common cache stored in
~/.cache/nix/fetcher-cache-v1.sqlite. This replaces the ad hoc caching
mechanisms in fetchGit and download.cc (e.g. ~/.cache/nix/{tarballs,git-revs*}).

This also adds support for Git worktrees (c169ea5904).
2020-04-07 09:03:14 +02:00
Cole Helbling c976cb0b8a
Don't retry on "unsupported protocol" error
When encountering an unsupported protocol, there's no need to retry.
Chances are, it won't suddenly be supported between retry attempts;
error instead. Otherwise, you see something like the following:

    $ nix-env -i -f git://git@github.com/foo/bar
    warning: unable to download 'git://git@github.com/foo/bar': Unsupported protocol (1); retrying in 335 ms
    warning: unable to download 'git://git@github.com/foo/bar': Unsupported protocol (1); retrying in 604 ms
    warning: unable to download 'git://git@github.com/foo/bar': Unsupported protocol (1); retrying in 1340 ms
    warning: unable to download 'git://git@github.com/foo/bar': Unsupported protocol (1); retrying in 2685 ms

With this change, you now see:

    $ nix-env -i -f git://git@github.com/foo/bar
    error: unable to download 'git://git@github.com/foo/bar': Unsupported protocol (1)
2020-04-05 09:00:34 -07:00
mlatus 12556e5709 fix placeholder not substituted in passAsFile 2020-03-31 19:40:16 +08:00
John Ericson 51afea3af2 Never cast FileIngestionMethod to or from boolean 2020-03-30 22:31:51 +00:00
John Ericson c251b011cd Merge remote-tracking branch 'upstream/master' into enum-FileIngestionMethod 2020-03-30 18:16:44 -04:00
Eelco Dolstra e322a16523 Remove global -I flags
(cherry picked from commit 2c692a3b14)
2020-03-30 15:30:19 +02:00
John Ericson 225e62a56a Replace some bool recursive with a new FileIngestionMethod enum 2020-03-29 15:16:20 -04:00
Eelco Dolstra 0a10854f85 Misc changes from the flakes branch 2020-03-24 14:34:47 +01:00
Eelco Dolstra 777e21e596 nix path-info --json: Print hash in SRI format
(cherry picked from commit 442e665d6d)
2020-03-24 14:26:23 +01:00
Eelco Dolstra f9611c7ae4 buildenv: Eliminate global variables, other cleanup
(cherry picked from commit b82f75464d)
2020-03-24 14:06:47 +01:00
Eelco Dolstra edc34cc1a2 Add function for quoting strings
(cherry picked from commit 7dcf5b011a)
2020-03-24 13:44:04 +01:00
Eelco Dolstra 5a7e7fc35f Use std::string_view
(cherry picked from commit 6529490cc1)
2020-03-24 13:26:37 +01:00
Eelco Dolstra 5885e20404
Merge pull request #3429 from LnL7/darwin-sandbox
darwin sandbox
2020-03-23 09:13:36 +01:00
Daiderd Jordan 2e9bc1245c
sandbox: fix /bin/sh on catalina
Sadly 10.15 changed /bin/sh to a shim which executes bash, this means it
can't be used anymore without also opening up the sandbox to allow bash.

    Failed to exec /bin/bash as variant for /bin/sh (1: Operation not permitted).
2020-03-20 22:12:30 +01:00
Daiderd Jordan f6c122aaeb
sandbox: allow pty devices
Nix now runs builds with a pseudo-terminal to enable colored build
output.
2020-03-20 21:58:45 +01:00
Daiderd Jordan 7f2df903d9
libstore: relax default sandbox-paths on darwin 2020-03-20 21:31:20 +01:00
Daiderd Jordan afb78ebd34
libstore: disable resolve-system-dependencies hook
This is used to determine the dependency tree of impure libraries so nix
knows what paths to open in the sandbox.  With the less restrictive
defaults it isn't needed anymore.
2020-03-20 21:21:56 +01:00
Eelco Dolstra b816515f61
Fix ca-references feature check
Fixes #3406.
2020-03-13 13:15:51 +01:00
Robert Hensing 3f55f8a8fb pathInfoCache: Respect disk cache TTLs #3398 2020-03-12 10:30:28 +01:00
Eelco Dolstra d37dc71e3c
nix-build: Fix !<output> handling
This was broken by 22a754c091.

https://hydra.nixos.org/eval/1573669
2020-03-04 13:56:17 +01:00
Eelco Dolstra 75db069f92
Optimise Derivation::unparse()
In

  nix-instantiate --dry-run '<nixpkgs/nixos/release-combined.nix>' -A nixos.tests.simple.x86_64-linux

this reduces time spent in unparse() from 9.15% to 4.31%. The main
culprit was appending characters one at a time to the destination
string. Even though the string has enough capacity, push_back() still
needs to check this on every call.
2020-03-04 11:44:45 +01:00
Eelco Dolstra 22a754c091
Fix GC failures on bad store path names
It failed on names like '/nix/store/9ip48nkc9rfy0a4yaw98lp6gipqlib1a-'.
2020-02-28 18:07:10 +01:00
Eelco Dolstra c4d3674de6
Merge pull request #3353 from tbsmoest/priv_tobias_pr_set_deathsig-1.4
Fix PR_SET_PDEATHSIG results in Broken pipe (#2395)
2020-02-19 12:29:12 +01:00
Eelco Dolstra 553e584f92
LocalStore::checkDerivationOutputs(): Improve error message 2020-02-18 17:51:48 +01:00
Tobias Möst 3e347220c8 Fix PR_SET_PDEATHSIG results in Broken pipe (#2395)
The ssh client is lazily started by the first worker thread, that
requires a ssh connection. To avoid the ssh client to be killed, when
the worker process is stopped, do not set PR_SET_PDEATHSIG.
2020-02-14 07:51:44 +01:00
Eelco Dolstra d8972317fc Prevent uninitialized StorePath creation 2020-02-13 16:12:16 +01:00
Eelco Dolstra d82b78bf51
Fix segfault in gcc on i686-linux
src/libstore/ssh-store.cc: In constructor 'nix::SSHStore::SSHStore(const string&, const Params&)':
  src/libstore/ssh-store.cc:31:21: internal compiler error: Segmentation fault
               compress)
                       ^
  Please submit a full bug report,
  with preprocessed source if appropriate.

https://hydra.nixos.org/build/111545609
2020-02-07 13:01:48 +01:00
Eelco Dolstra db88cb401b
Merge pull request #3344 from LnL7/ssh-ng-remote-params
ssh-store: add remote-store and remote-program query params
2020-02-04 10:10:08 +01:00
Daiderd Jordan 8745c63d3c
ssh-store: add remote-store and remote-program query params
Brings the functionality of ssh-ng:// in sync with the legacy ssh://
implementation.  Specifying the remote store uri enables various useful
things. eg.

    $ nix copy --to ssh-ng://cache?remote-store=file://mnt/cache --all
2020-02-03 23:22:28 +01:00
Eelco Dolstra 7be1a07a45
Merge pull request #3335 from domenkozar/retry-429
retry on HTTP status code 429
2020-01-29 16:22:46 +01:00
Domen Kožar 48ddb8e481
retry on HTTP status code 429 2020-01-29 11:47:39 +01:00
Robin Gloster f8dbde0813
structured-attrs: chown .attrs.* files to builder
Otherwise `chmod .`'ing the build directory doesn't work anymore, which
is done in nixpkgs if sourceRoot is set to '.'.
2020-01-23 17:38:07 +01:00
Eelco Dolstra d506bd587a Fix clang warning 2020-01-22 21:20:01 +01:00
Eelco Dolstra aef635da78 Fix derivation computation with __structuredAttrs and multiple outputs
Fixes

  error: derivation '/nix/store/klivma7r7h5lndb99f7xxmlh5whyayvg-zlib-1.2.11.drv' has incorrect output '/nix/store/fv98nnx5ykgbq8sqabilkgkbc4169q05-zlib-1.2.11-dev', should be '/nix/store/adm7pilzlj3z5k249s8b4wv3scprhzi1-zlib-1.2.11-dev'
2020-01-21 21:14:13 +01:00
Daiderd Jordan 8b3217f832
build: remove warning when in sandboxing test mode
Introduced in 66fccd5832, but somehow
breaks the secure-drv-outputs test.
2020-01-13 22:09:18 +01:00
John Ericson d64ab5131c unbreak build without pch 2020-01-13 21:45:33 +01:00
Eelco Dolstra bc22a7ee6a Fix use of uninitialized store path
Fixes 'building of '/nix/store/00000000000000000000000000000000-': ...'.
2020-01-06 22:20:10 +01:00
Eelco Dolstra e2988f48a1
Merge pull request #3303 from LnL7/darwin-sandbox
build: fix sandboxing on darwin
2020-01-06 20:56:35 +01:00
Daiderd Jordan 66fccd5832
build: fix sandboxing on darwin
Starting ba87b08f85 getEnv now returns an
std::optional which means these getEnv() != "" conditions no longer happen
if the variables are not defined.
2020-01-05 20:23:52 +01:00
Daiderd Jordan 7d448bc966
build: fix path repairing when hash rewriting is required
Handle store path repairing on darwin when sandboxing is enabled. Unlike
on linux sandboxing on darwin still requires hash rewriting.
2020-01-04 20:25:25 +01:00
Daiderd Jordan b33fefcb92
build: recover store path when replacing fails
This shouldn't happen in normal circumstances, but just in case
attempt to move the temporary path back if possible.
2020-01-04 20:24:27 +01:00
edef c65a6fa86a passAsFile: leave out the hash prefix
Having a colon in the path may cause issues, and having the hash
function indicated isn't actually necessary. We now verify the path 
format in the tests to prevent regressions.
2020-01-02 23:56:06 +00:00
Puck Meerburg 515c0a263e passAsFile: hash the attribute name instead of numbering sequentially
This makes the paths consistent without relying on ordering.

Co-authored-by: edef <edef@edef.eu>
2020-01-02 22:56:03 +00:00
Graham Christensen c502831a1d
exportReferencesGraph: support working
Before, we would get:

    [deploy@bastion:~]$ nix-store -r /nix/store/grfnl76cahwls0igd2by2pqv0dimi8h2-nixos-system-eris-19.09.20191213.03f3def.drv
    these derivations will be built:
      /nix/store/3ka4ihvwh6wsyhpd2qa9f59506mnxvx1-initrd-linux-4.19.88.drv
      /nix/store/ssxwmll7v21did1c8j027q0m8w6pg41i-unit-prometheus-alertmanager-irc-notifier.service.drv
      /nix/store/mvyvkj46ay7pp7b1znqbkck2mq98k0qd-unit-script-network-local-commands-start.drv
      /nix/store/vsl1y9mz38qfk6pyirjwnfzfggz5akg6-unit-network-local-commands.service.drv
      /nix/store/wi5ighfwwb83fdmav6z6n2fw6npm9ffl-unit-prometheus-hydra-exporter.service.drv
      /nix/store/x0qkv535n75pbl3xn6nn1w7qkrg9wwyg-unit-prometheus-packet-sd.service.drv
      /nix/store/lv491znsjxdf51xnfxh9ld7r1zg14d52-unit-script-packet-sd-env-key-pre-start.drv
      /nix/store/nw4nzlca49agsajvpibx7zg5b873gk9f-unit-script-packet-sd-env-key-start.drv
      /nix/store/x674wwabdwjrkhnykair4c8mpxa9532w-unit-packet-sd-env-key.service.drv
      /nix/store/ywivz64ilb1ywlv652pkixw3vxzfvgv8-unit-wireguard-wg0.service.drv
      /nix/store/v3b648293g3zl8pnn0m1345nvmyd8dwb-unit-script-acme-selfsigned-status.nixos.org-start.drv
      /nix/store/zci5d3zvr6fgdicz6k7jjka6lmx0v3g4-unit-acme-selfsigned-status.nixos.org.service.drv
      /nix/store/f6pwvnm63d0kw5df0v7sipd1rkhqxk5g-system-units.drv
      /nix/store/iax8071knxk9c7krpm9jqg0lcrawf4lc-etc.drv
      /nix/store/grfnl76cahwls0igd2by2pqv0dimi8h2-nixos-system-eris-19.09.20191213.03f3def.drv
    error: invalid file name 'closure-init-0' in 'exportReferencesGraph'

This was tough to debug, I didn't figure out which one was broken until I did:

    nix-store -r /nix/store/grfnl76cahwls0igd2by2pqv0dimi8h2-nixos-system-eris-19.09.20191213.03f3def.drv 2>&1 | grep  nix/store | xargs -n1 nix-store -r

and then looking at the remaining build graph:

    $ nix-store -r /nix/store/grfnl76cahwls0igd2by2pqv0dimi8h2-nixos-system-eris-19.09.20191213.03f3def.drv
    these derivations will be built:
      /nix/store/3ka4ihvwh6wsyhpd2qa9f59506mnxvx1-initrd-linux-4.19.88.drv
      /nix/store/grfnl76cahwls0igd2by2pqv0dimi8h2-nixos-system-eris-19.09.20191213.03f3def.drv
    error: invalid file name 'closure-init-0' in 'exportReferencesGraph'

and knowing the initrd build is before the system, then:

    $ nix show-derivation /nix/store/3ka4ihvwh6wsyhpd2qa9f59506mnxvx1-initrd-linux-4.19.88.drv
    {
      "/nix/store/3ka4ihvwh6wsyhpd2qa9f59506mnxvx1-initrd-linux-4.19.88.drv": {
        [...]
        "exportReferencesGraph": "closure-init-0 /nix/store/...-stage-1-init.sh closure-mdadm.conf-1 /nix/store/...-mdadm.conf closure-ubuntu.conf-2 ...",
        [...]
      }
    }

I then searched the repo for "in 'exportReferencesGraph'", found this
recently updated regex, and realized it was missing a "-".
2020-01-01 20:50:40 -05:00
Brian McKenna d25923263e Disable use-sqlite-wal under WSL
Before:

    $ nix-channel --update
    unpacking channels...
    warning: SQLite database '/nix/var/nix/db/db.sqlite' is busy (SQLITE_PROTOCOL)
    warning: SQLite database '/nix/var/nix/db/db.sqlite' is busy (SQLITE_PROTOCOL)
    warning: SQLite database '/nix/var/nix/db/db.sqlite' is busy (SQLITE_PROTOCOL)
    warning: SQLite database '/nix/var/nix/db/db.sqlite' is busy (SQLITE_PROTOCOL)
    warning: SQLite database '/nix/var/nix/db/db.sqlite' is busy (SQLITE_PROTOCOL)

After:

    $ inst/bin/nix-channel --update
    unpacking channels...
    created 1 symlinks in user environment

I've seen complaints that "sandbox" caused problems under WSL but I'm
having no problems. I think recent changes could have fixed the issue.
2019-12-21 08:14:19 +11:00
Eelco Dolstra ee235e764c
Merge branch 'libarchive' of https://github.com/yorickvP/nix 2019-12-19 14:47:18 +01:00
Eelco Dolstra f8abbdd456 Add priority setting to stores
This allows overriding the priority of substituters, e.g.

  $ nix-store --store ~/my-nix/ -r /nix/store/df3m4da96d84ljzxx4mygfshm1p0r2n3-geeqie-1.4 \
    --substituters 'http://cache.nixos.org?priority=100 daemon?priority=10'

Fixes #3264.
2019-12-17 17:17:53 +01:00
Eelco Dolstra 54bf5ba422 nix-store -r: Handle symlinks to store paths
Fixes #3270.
2019-12-16 19:11:47 +01:00
Eelco Dolstra e8aa2290ed Only install *.sb files on macOS 2019-12-13 14:42:55 +01:00
Eelco Dolstra d1b238ec3c Simplify 2019-12-13 12:53:20 +01:00
Profpatsch 38b29fb72c libstore/ssh: Improve error message on failing execvp
If the `throw` is reached, this means that execvp into `ssh` wasn’t
successful. We can hint at a usual problem, which is a missing `ssh`
executable.

Test with:

```
env PATH= ./result/bin/nix-copy-closure --builders '' unusedhost
```

and the bash version with

```
env PATH= ./result/bin/nix-copy-closure --builders '' localhost
```
2019-12-12 15:32:17 +01:00
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