Strings are now printed directly when evaluated by `:print`, rather than
escaped. This makes it easier to debug multi-line strings or strings
containing quotes, like the results of `builtins.readFile`,
`lib.toShellArg`, and so on.
```
nix-repl> "cuppy\ndog\ncity"
"cuppy\ndog\ncity"
nix-repl> :p "cuppy\ndog\ncity"
cuppy
dog
city
```
Fixes this very long warning, which I'll only include the first line of:
/nix/store/8wrjhrycpshhc3b41xmjwvgqr2m3yajq-libcxx-16.0.6-dev/include/c++/v1/__memory/construct_at.h:66:5: warning: destructor called on non-final 'RegexMatcher' that has virtual functions but non-virtual destructor [-Wdelete-non-abstract-non-virtual-dtor]
__loc->~_Tp();
`nix eval` forces values and prints derivations as attribute sets, so
commands that print derivations (e.g. `nix eval nixpkgs#bash`) will
infinitely loop and segfault.
Printing derivations as `.drv` paths makes `nix eval` complete as
expected. Further work is needed, but this is better than a segfault.
`nix-env -qaP`'s output has changed a bit because of https://github.com/NixOS/nix/issues/10132.
Although that's a bit annoying, it isn't nearly as problematic as the
evaluation changes that this test is supposed to catch. So it's find to
just update the hash for the time being and fix the issue later
(properly fixing the issue will very likely change the hash any way).
Currently there isn't a convenient way to check for multiline output. In
addition, these outputs will easily change and having a diff between the
expected an the actual output upon failures is convenient.
This wasn't caught by CI because #10149 and #10152 pass
individually... It doesn't happen on lazy-trees either because we
never try to fetch relative path flakes (#10089).
we now keep not a table of all positions, but a table of all origins and
their sizes. position indices are now direct pointers into the virtual
concatenation of all parsed contents. this slightly reduces memory usage
and time spent in the parser, at the cost of not being able to report
positions if the total input size exceeds 4GiB. this limit is not unique
to nix though, rustc and clang also limit their input to 4GiB (although
at least clang refuses to process inputs that are larger, we will not).
this new 4GiB limit probably will not cause any problems for quite a
while, all of nixpkgs together is less than 100MiB in size and already
needs over 700MiB of memory and multiple seconds just to parse. 4GiB
worth of input will easily take multiple minutes and over 30GiB of
memory without even evaluating anything. if problems *do* arise we can
probably recover the old table-based system by adding some tracking to
Pos::Origin (or increasing the size of PosIdx outright), but for time
being this looks like more complexity than it's worth.
since we now need to read the entire input again to determine the
line/column of a position we'll make unsafeGetAttrPos slightly lazy:
mostly the set it returns is only used to determine the file of origin
of an attribute, not its exact location. the thunks do not add
measurable runtime overhead.
notably this change is necessary to allow changing the parser since
apparently nothing supports nix's very idiosyncratic line ending choice
of "anything goes", making it very hard to calculate line/column
positions in the parser (while byte offsets are very easy).
