Commit graph

1856 commits

Author SHA1 Message Date
Shea Levy 18fefacf7d Dynamic attrs
This adds new syntax for attribute names:

* attrs."${name}" => getAttr name attrs
* attrs ? "${name}" => isAttrs attrs && hasAttr attrs name
* attrs."${name}" or def => if attrs ? "${name}" then attrs."${name}" else def
* { "${name}" = value; } => listToAttrs [{ inherit name value; }]

Of course, it's a bit more complicated than that. The attribute chains
can be arbitrarily long and contain combinations of static and dynamic
parts (e.g. attrs."${foo}".bar."${baz}" or qux), which is relatively
straightforward for the getAttrs/hasAttrs cases but is more complex for
the listToAttrs case due to rules about duplicate attribute definitions.

For attribute sets with dynamic attribute names, duplicate static
attributes are detected at parse time while duplicate dynamic attributes
are detected when the attribute set is forced. So, for example, { a =
null; a.b = null; "${"c"}" = true; } will be a parse-time error, while
{ a = {}; "${"a"}".b = null; c = true; } will be an eval-time error
(technically that case could theoretically be detected at parse time,
but the general case would require full evaluation). Moreover, duplicate
dynamic attributes are not allowed even in cases where they would be
with static attributes ({ a.b.d = true; a.b.c = false; } is legal, but {
a."${"b"}".d = true; a."${"b"}".c = false; } is not). This restriction
might be relaxed in the future in cases where the static variant would
not be an error, but it is not obvious that that is desirable.

Finally, recursive attribute sets with dynamic attributes have the
static attributes in scope but not the dynamic ones. So rec { a = true;
"${"b"}" = a; } is equivalent to { a = true; b = true; } but rec {
"${"a"}" = true; b = a; } would be an error or use a from the
surrounding scope if it exists.

Note that the getAttr, getAttr or default, and hasAttr are all
implemented purely in the parser as syntactic sugar, while attribute
sets with dynamic attribute names required changes to the AST to be
implemented cleanly.

This is an alternative solution to and closes #167

Signed-off-by: Shea Levy <shea@shealevy.com>
2013-12-31 20:59:49 +00:00
Shea Levy 136f2f7046 Add the ExprBuiltin Expr type to the AST
Certain desugaring schemes may require the parser to use some builtin
function to do some of the work (e.g. currently `throw` is used to
lazily cause an error if a `<>`-style path is not in the search path)
Unfortunately, these names are not reserved keywords, so an expression
that uses such a syntactic sugar will not see the expected behavior
(see tests/lang/eval-okay-redefine-builtin.nix for an example).

This adds the ExprBuiltin AST type, which when evaluated uses the value
from the rootmost variable scope (which of course is initialized
internally and can't shadow any of the builtins).

Signed-off-by: Shea Levy <shea@shealevy.com>
2013-12-31 17:45:47 +00:00
Eelco Dolstra 8931bf7168 Doh 2013-12-20 13:09:12 +00:00
Eelco Dolstra 7d203faff6 nix-env --set-flag: Barf if a selector doesn't match any installed package
Fixes #184.
2013-12-20 13:56:42 +01:00
Eelco Dolstra 769f662165 nix-shell: Don't warn about the lack of a GC root 2013-12-20 12:19:10 +00:00
Eelco Dolstra 65a6452240 nix-shell: Handle --option correctly
Fixes #181.
2013-12-20 13:10:14 +01:00
Shea Levy e36229d27f Bump language version for new storePath feature
This will allow e.g. channel expressions to use builtins.storePath IFF
it is safe to do so without knowing if the path is valid yet.

Signed-off-by: Shea Levy <shea@shealevy.com>
2013-12-10 15:07:04 +01:00
Shea Levy 22d665019a builtins.storePath: Try to substitute the path if it is not yet valid
Signed-off-by: Shea Levy <shea@shealevy.com>
2013-12-10 15:07:04 +01:00
Eelco Dolstra a6add93d73 Garbage collector: Release locks on temporary root files
This allows processes waiting for such locks to proceed during the
trash deletion phase of the garbage collector.
2013-12-10 13:13:59 +01:00
Eelco Dolstra c5b8fe3151 Print a trace message if a build fails due to the platform being unknown 2013-12-05 14:31:57 -05:00
Eelco Dolstra 709cbe4e76 Include <cstring> for memset
This should fix building on Illumos.
2013-11-22 10:00:43 +00:00
Eelco Dolstra 30b986908e Check meta values and warn about bad ones 2013-11-19 14:29:39 +01:00
Eelco Dolstra 0f24400d90 Generalise meta attributes 2013-11-19 14:09:14 +01:00
Eelco Dolstra 990126cde0 Shorter error message 2013-11-19 14:09:14 +01:00
Eelco Dolstra af94a70ba6 Drop support for user environment manifests in ATerm format 2013-11-19 14:09:14 +01:00
Eelco Dolstra 245e26408f nix-env -q: Add a --json flag 2013-11-19 00:41:45 +01:00
Eelco Dolstra 5fea98111b Refactor JSON output 2013-11-19 00:33:06 +01:00
Eelco Dolstra 77c13cdf56 Add a toJSON primop 2013-11-19 00:04:11 +01:00
Eelco Dolstra 285df765b9 Add a primop unsafeGetAttrPos to return the position of an attribute 2013-11-18 22:22:35 +01:00
Eelco Dolstra fc33fd86b7 Add a symbol __curPos that expands to the current source location
I.e. an attribute set { file = <string>; line = <int>; column = <int>; }.
2013-11-18 20:16:02 +01:00
Eelco Dolstra 90b5e69284 Support quoted attribute names in -A
This is requires if you have attribute names with dots in them.  So
you can now say:

  $ nix-instantiate '<nixos>' -A 'config.systemd.units."postgresql.service".text' --eval-only

Fixes #151.
2013-11-18 10:21:12 +00:00
Eelco Dolstra a478e8a7bb Remove nix-setuid-helper
AFAIK, nobody uses it, it's not maintained, and it has no tests.
2013-11-14 11:57:37 +01:00
Eelco Dolstra 89e6781cc5 Make function calls show up in stack traces again
Note that adding --show-trace prevents functions calls from being
tail-recursive, so an expression that evaluates without --show-trace
may fail with a stack overflow if --show-trace is given.
2013-11-12 12:51:59 +01:00
Eelco Dolstra c897bac549 Make function calls tail-recursive 2013-11-12 11:32:23 +00:00
Eelco Dolstra 273322c773 Make ifs and asserts tail-recursive
The local Value object prevented g++ from making a tail call.  Not
clear why.  In any case, not using a temporary makes g++ do the tail
call.
2013-11-12 11:32:23 +00:00
Eelco Dolstra 4badd7ed17 Get rid of an intermediary on the stack 2013-11-12 11:32:23 +00:00
Eelco Dolstra 8d6418d46e Fix building without a garbage collector
http://hydra.nixos.org/build/6695350
2013-10-28 22:51:12 +01:00
Eelco Dolstra dec2f19502 Fix a segfault in genericClosure
It kept temporary data in STL containers that were not scanned by
Boehm GC, so Nix programs using genericClosure could randomly crash if
the garbage collector kicked in at a bad time.

Also make it a bit more efficient by copying points to values rather
than values.
2013-10-28 18:52:26 +01:00
Eelco Dolstra ea6bf0c21f Slightly optimize listToAttrs 2013-10-28 07:34:44 +01:00
Eelco Dolstra 5bc41d78ff Rename "attribute sets" to "sets"
We don't have any other kind of sets so calling them attribute sets is
unnecessarily verbose.
2013-10-24 16:41:04 +02:00
Eelco Dolstra 69befd33a9 Remove unnecessary call to forceStringNoCtx 2013-10-24 03:08:34 +02:00
Eelco Dolstra 05d02f798f Add a typeOf primop
We already have some primops for determining the type of a value, such
as isString, but they're incomplete: for instance, there is no isPath.
Rather than adding more isBla functions, the generic typeOf function
returns a string representing the type of the argument (e.g. "int").
2013-10-24 02:49:13 +02:00
Eelco Dolstra 543d8a5942 Don't require NIX_SHOW_STATS for NIX_COUNT_CALLS 2013-10-24 02:20:54 +02:00
Eelco Dolstra fe95650487 Memoize evalFile() lookups under both the original and resolved name
Previously we only used the resolved name, causing repeated resolution
(e.g. /dir to /dir/default.nix).
2013-10-23 11:19:01 +00:00
Eelco Dolstra c086183843 For auto roots, show the intermediate link
I.e. "nix-store -q --roots" will now show (for example)

  /home/eelco/Dev/nixpkgs/result

rather than

  /nix/var/nix/gcroots/auto/53222qsppi12s2hkap8dm2lg8xhhyk6v
2013-10-22 11:39:10 +02:00
Eelco Dolstra 792fd51f41 Fold two stack trace messages in derivations
Combined with the previous changes, stack traces involving derivations
are now much less verbose, since something like

  while evaluating the builtin function `getAttr':
  while evaluating the builtin function `derivationStrict':
  while instantiating the derivation named `gtk+-2.24.20' at `/home/eelco/Dev/nixpkgs/pkgs/development/libraries/gtk+/2.x.nix:11:3':
  while evaluating the derivation attribute `propagatedNativeBuildInputs' at `/home/eelco/Dev/nixpkgs/pkgs/stdenv/generic/default.nix:78:17':
  while evaluating the attribute `outPath' at `/nix/store/212ngf4ph63mp6p1np2bapkfikpakfv7-nix-1.6/share/nix/corepkgs/derivation.nix:18:9':
  ...

now reads

  while evaluating the attribute `propagatedNativeBuildInputs' of the derivation `gtk+-2.24.20' at `/home/eelco/Dev/nixpkgs/pkgs/development/libraries/gtk+/2.x.nix:11:3':
  ...
2013-10-17 11:57:25 +02:00
Eelco Dolstra f440558acc Don't show <nix/derivation.nix> in stack traces
Messages like

  while evaluating the attribute `outPath' at `/nix/store/212ngf4ph63mp6p1np2bapkfikpakfv7-nix-1.6/share/nix/corepkgs/derivation.nix:18:9':

are redundant, because Nix already shows that it's evaluating a derivation:

  while instantiating the derivation named `firefox-24.0' at `/home/eelco/Dev/nixpkgs/pkgs/applications/networking/browsers/firefox/default.nix:131:5':
  while evaluating the derivation attribute `nativeBuildInputs' at `/home/eelco/Dev/nixpkgs/pkgs/stdenv/generic/default.nix:76:17':
2013-10-17 11:47:38 +02:00
Eelco Dolstra b8034e5581 Ensure proper type checking/coercion of "${expr}"
Now we only rewrite "${expr}" to expr if expr is a string literal.
2013-10-17 00:57:24 +02:00
Eelco Dolstra d6a7aa8f48 Revert the behaviour of antiquoted paths to pre-Nix 1.6
Commit 159e621d1a accidentally changed
the behaviour of antiquoted paths, e.g.

  "${/foo}/bar"

used to evaluate to "/nix/store/<hash>-foo/bar" (where /foo gets
copied to the store), but in Nix 1.6 it evaluates to "/foo/bar".  This
is inconsistent, since

  " ${/foo}/bar"

evaluates to " /nix/store/<hash>-foo/bar".  So revert to the old
behaviour.
2013-10-17 00:39:59 +02:00
Eelco Dolstra a737f51fd9 Retry all SQLite operations
To deal with SQLITE_PROTOCOL, we also need to retry read-only
operations.
2013-10-16 15:58:20 +02:00
Eelco Dolstra ff02f5336c Fix a race in registerFailedPath()
Registering the path as failed can fail if another process does the
same thing after the call to hasPathFailed().  This is extremely
unlikely though.
2013-10-16 14:55:53 +02:00
Eelco Dolstra 4bd5282573 Convenience macros for retrying a SQLite transaction 2013-10-16 14:46:35 +02:00
Eelco Dolstra bce14d0f61 Don't wrap read-only queries in a transaction
There is no risk of getting an inconsistent result here: if the ID
returned by queryValidPathId() is deleted from the database
concurrently, subsequent queries involving that ID will simply fail
(since IDs are never reused).
2013-10-16 14:36:53 +02:00
Eelco Dolstra 7cdefdbe73 Print a distinct warning for SQLITE_PROTOCOL 2013-10-16 14:27:36 +02:00
Eelco Dolstra d05bf04444 Treat SQLITE_PROTOCOL as SQLITE_BUSY
In the Hydra build farm we fairly regularly get SQLITE_PROTOCOL errors
(e.g., "querying path in database: locking protocol").  The docs for
this error code say that it "is returned if some other process is
messing with file locks and has violated the file locking protocol
that SQLite uses on its rollback journal files."  However, the SQLite
source code reveals that this error can also occur under high load:

  if( cnt>5 ){
    int nDelay = 1;                      /* Pause time in microseconds */
    if( cnt>100 ){
      VVA_ONLY( pWal->lockError = 1; )
      return SQLITE_PROTOCOL;
    }
    if( cnt>=10 ) nDelay = (cnt-9)*238;  /* Max delay 21ms. Total delay 996ms */
    sqlite3OsSleep(pWal->pVfs, nDelay);
  }

i.e. if certain locks cannot be not acquired, SQLite will retry a
number of times before giving up and returing SQLITE_PROTOCOL.  The
comments say:

  Circumstances that cause a RETRY should only last for the briefest
  instances of time.  No I/O or other system calls are done while the
  locks are held, so the locks should not be held for very long. But
  if we are unlucky, another process that is holding a lock might get
  paged out or take a page-fault that is time-consuming to resolve,
  during the few nanoseconds that it is holding the lock.  In that case,
  it might take longer than normal for the lock to free.
  ...
  The total delay time before giving up is less than 1 second.

On a heavily loaded machine like lucifer (the main Hydra server),
which often has dozens of processes waiting for I/O, it seems to me
that a page fault could easily take more than a second to resolve.
So, let's treat SQLITE_PROTOCOL as SQLITE_BUSY and retry the
transaction.

Issue NixOS/hydra#14.
2013-10-16 14:19:59 +02:00
Eelco Dolstra 7bdb85453d printStats(): Print the size of the symbol table in bytes 2013-10-08 15:37:08 +02:00
Eelco Dolstra 9deb822180 Deduplicate filenames in Pos
This saves ~4 MiB of RAM for NixOS system instantiation, and ~18 MiB
for "nix-env -qa".
2013-10-08 15:36:10 +02:00
Eelco Dolstra b1e3b1a4ac Treat undefined variable errors consistently
Previously, a undefined variable inside a "with" caused an EvalError
(which can be caught), while outside, it caused a ParseError (which
cannot be caught).  Now both cause an UndefinedVarError (which cannot
be caught).
2013-10-08 14:45:36 +02:00
Eelco Dolstra 6b47de580f Show the exact position of undefined variables
In particular, undefined variable errors in a "with" previously didn't
show *any* position information, so this should help a lot in those
cases.
2013-10-08 14:40:51 +02:00
Eelco Dolstra a5e0f64db3 Remove some unused functions 2013-10-08 12:30:23 +00:00