Allows checking directory entry type of a single file/directory.
This was added to optimize the use of `builtins.readDir` on some
filesystems and operating systems which cannot detect this information
using POSIX's `readdir`.
Previously `builtins.readDir` would eagerly use system calls to lookup
these filetypes using other interfaces; this change makes these
operations lazy in the attribute values for each file with application
of `builtins.readFileType`.
Prior to this change, we had a bunch of ad-hoc string manipulation code
scattered around. This made it hard to figure out what data model for
string contexts is.
Now, we still store string contexts most of the time as encoded strings
--- I was wary of the performance implications of changing that --- but
whenever we parse them we do so only through the
`NixStringContextElem::parse` method, which handles all cases. This
creates a data type that is very similar to `DerivedPath` but:
- Represents the funky `=<drvpath>` case as properly distinct from the
others.
- Only encodes a single output, no wildcards and no set, for the
"built" case.
(I would like to deprecate `=<path>`, after which we are in spitting
distance of `DerivedPath` and could maybe get away with fewer types, but
that is another topic for another day.)
Without the change checks issue the fllowing warning:
$ nix flake check
trace: warning: The option `nix.useSandbox' defined in `makeTest parameters' has been renamed to `nix.settings.sandbox'.
trace: warning: The option `nix.useSandbox' defined in `makeTest parameters' has been renamed to `nix.settings.sandbox'.
trace: warning: The option `nix.maxJobs' defined in `makeTest parameters' has been renamed to `nix.settings.max-jobs'.
...
First, logic is consolidated in the shell script instead of being spread
between them and makefiles. That makes understanding what is going on a
little easier.
This would not be super interesting by itself, but it gives us a way to
debug tests more easily. *That* in turn I hope is much more compelling.
See the updated manual for details.
Co-authored-by: Valentin Gagarin <valentin.gagarin@tweag.io>
Co-authored-by: Eelco Dolstra <edolstra@gmail.com>
Co-authored-by: Robert Hensing <roberth@users.noreply.github.com>
This makes 'nix build' work on paths (which will be copied to the
store) and store paths (returned as is). E.g. the following flake
output attributes can be built using 'nix build .#foo':
foo = ./src;
foo = self.outPath;
foo = builtins.fetchTarball { ... };
foo = (builtins.fetchTree { .. }).outPath;
foo = builtins.fetchTree { .. } + "/README.md";
foo = builtins.storePath /nix/store/...;
Note that this is potentially risky, e.g.
foo = /.;
will cause Nix to try to copy the entire file system to the store.
What doesn't work yet:
foo = self;
foo = builtins.fetchTree { .. };
because we don't handle attrsets with an outPath attribute in it yet,
and
foo = builtins.storePath /nix/store/.../README.md;
since result symlinks have to point to a store path currently (rather
than a file inside a store path).
Fixes#7417.
This makes the position object used in exceptions abstract, with a
method getSource() to get the source code of the file in which the
error originated. This is needed for lazy trees because source files
don't necessarily exist in the filesystem, and we don't want to make
libutil depend on the InputAccessor type in libfetcher.
Fix#6209
When trying to run `nix log <installable>`, try first to resolve the derivation pointed to
by `<installable>` as it is the resolved one that holds the build log.
This has a couple of shortcomings:
1. It’s expensive as it requires re-reading the derivation
2. It’s brittle because if the derivation doesn’t exist anymore or can’t
be resolved (which is the case if any one of its build inputs is missing),
then we can’t access the log anymore
However, I don’t think we can do better (at least not right now).
The alternatives I see are:
1. Copy the build log for the un-resolved derivation. But that means a
lot of duplication
2. Store the results of the resolving in the db. Which might be the best
long-term solution, but leads to a whole new class of potential
issues.
Linus Heckemann
Robert Hensing
Yorick