flat_charged and the property-key path now root the rope itself, so a string held only by
native code (a getter's result for ++o.x, a valueOf result, a toString key) still counts
what it holds when the reservation collects. The per-call roots for these cases are removed.
When the flattened copy of a String object's concatenated string would pass the heap limit
before a collection can run, the indexed read walks the rope to the unit instead, taking a
unit of fuel for each node it visits, so no copy is made.
- wrapping a string no longer flattens it, so Object(s).length and new String(s) on a large concatenated string make no copy and cannot collect while a call's operands are off the stack
- reading a String object's character by index, `in` and hasOwnProperty count the flattened copy at the next limit check, and the run ends before the copy when the fuel for it is not left
- unary plus on an object whose valueOf returns a concatenated string, and a property key from toString, keep that string rooted while its copy is reserved
- the unshift comment cites step 6 of section 15.4.4.13
Boxing the string receiver of a non-strict function flattens it, and reserving the copy can
collect. The callee, receiver and arguments are already off the stack at that point, so they
stay in the temporary roots until the frame holds them; before, an argument object could be
freed and its cell reused by the wrapper. new String(value) roots the converted string the
same way, so what the rope holds is still counted while its copy is reserved.
- the relational operators root both strings while flattening them, so the first copy still counts when the second one starts a collection
- join roots its separator for the whole join and each element while it is written, and JSON.stringify roots a string while it writes it
- a String object flattens its string when it is made, with the copy counted, so reading one of its characters copies nothing
xml.xpath(expression[, variables]) evaluates an XPath 1.0 expression
(https://www.w3.org/TR/1999/REC-xpath-19991116/) with the XML value as
the context node and returns the selected nodes as an XMLList, in
document order and without repeats. On an XMLList the expression runs
on each element in turn, and the results are joined.
- All 13 axes and the 27 core functions. id() selects nothing, since
E4X trees carry no DTD data.
- Each property of `variables` binds the variable of its name. A
prefix in a name test resolves through the context element's
in-scope namespaces; `xml` is always bound.
- An expression that breaks the grammar gives a SyntaxError. An
unknown function, a wrong argument count, an unbound prefix or
variable, a result that is not a node-set, and a result that holds
the root or a namespace node give a TypeError.
- The parser and the evaluator keep their state on their own stacks,
so expressions of any depth use no native stack; nesting past
Options::max_depth gives "nesting too deep". Traversal stacks, node
lists, strings and the values that string functions build count
against the heap limit, and every node visited and string read takes
fuel.
Docs: docs/target-app-parity.md (E4X line), crate doc in lib.rs.
The fuel and heap checks for a host evaluator's source were split into a third
before encoding and the rest after, so a source whose whole UTF-16 text did not
fit in the heap could still be encoded and parsed. The whole encoded size is now
reserved before encoding. A source over the source limit is still refused as a
syntax error.
A for each loop read the property's value before evaluating its target,
so a target such as (o.p = 2, t).v, t[(o.p = 3, 'w')] or a bare
@[(o.p = 2, 'k')] stored the value from before the target ran. The
target's object and name are now evaluated first and the value is read
after them (ECMA-357 section 12.3).
Flattening a concatenated string copies its units into a new buffer. The
string built-ins reserve that copy with flat_charged, but several other
paths flattened without it, so a script could build copies the heap limit
never saw:
- the relational operators (`<`, `>`, `<=`, `>=`) on two strings, `==`
between a string and a number, unary `+` and every other ToNumber of a
string, and reading a character by index (`s[0]`)
- a property name made from an object whose toString returns a long
string, and a long string used as a property name, which now reserves
its copy before it is made instead of after
- direct `eval` of a concatenated source
- `JSON.stringify` of a string value and its `space` argument
- `Array.prototype.join`'s separator and each string element it writes
Property names and eval source reserve the copy's heap bytes without
taking fuel.
Direct and indirect eval, Function and host evaluators parsed and compiled
their source before taking any fuel or checking the heap, so a script with a
small fuel limit could make the interpreter parse megabytes of source in a
handful of instructions. Interp::prepare_source now takes one unit of fuel for
each UTF-16 code unit and checks that the source text fits in the heap before
the source is flattened, parsed or compiled. A host evaluator's string takes
the fuel for a third of its bytes before it is encoded, and the rest after.
Limits::fuel and the maxFuel row in docs/mcp.md say so.
With Options::e4x set, an E4X name standing alone (@a, @ns::a, @[expr],
ns::a, *) is now a valid target for =, compound assignment, ++, --,
delete and for/for each loops, as well as a read. The target is the
nearest XML or XMLList value in scope whose [[HasProperty]] accepts the
name (ECMA-357 section 11.1). The name is evaluated once, and the
target resolves before the right-hand side runs.
When no XML value in scope holds the name, a read or write throws a
ReferenceError and creates no child or attribute. A read no longer
falls back to the first XML value in scope, so a filter such as
list.(@id == '1') throws when an item has no @id and no outer XML
value holds one, instead of treating that item as not matching.
An XML declaration at the start of XML or XMLList text was skipped up to
the next "?>" without being read. It is now checked against XML 1.0's
grammar (https://www.w3.org/TR/xml/#NT-XMLDecl): a version of "1." and
digits, then an optional encoding name and an optional standalone "yes"
or "no", in that order, with optional white space before "?>". Any other
declaration gives "SyntaxError: invalid XML declaration", and a character
XML does not allow gives "invalid character in XML text". White space
before the declaration is still accepted.
The parser now takes fuel for the length of the declaration and the
white space before it, element and attribute names, white space in open
and closing tags, and the text it searched when an attribute value, CDATA
section, comment or processing instruction is not closed, or when "]]>"
or "<" stops a text run or attribute value. A long run in any of these
used the same fuel as a short one.
A finally block that break or continue leaves no longer keeps the saved
site of the exception it ran for. A Jump now removes the sites at or
above the stack's length, as a return already does, so a collection
after the stack grows back over that slot does not root and count the
old code.
New tests in crates/js/src/host_tests.rs: an error passed on by a
finally block that collects garbage under a 1 MiB heap is reported at
its throw; the saved site keeps direct eval code live through a
collection; a host abort inside a finally block leaves no saved site;
and break, continue and return out of a finally block drop the site.
A literal makes an extensible object whose properties are writable and
configurable, and an array whose length is writable. toSource wrote a
property defined with writable or configurable false, a sealed, frozen or
non-extensible object or array, and an array with a read-only length as an
ordinary literal, so evaluating the text gave an open value.
toSource now throws a TypeError for each of these, at any depth, as it
already does for getters, hidden properties and other prototypes.
Properties defined with every flag on are written as before.
`inScopeNamespaces()`, `namespaceDeclarations()` and `namespace()` walk
from the node up to its root. The walk cloned each ancestor's whole node,
children and attributes included, to read its namespaces, and charged
fuel only for the namespaces it found, so a deep tree with no declared
namespaces cost no fuel. It now takes one unit of fuel per ancestor,
copies only the namespace list and parent link, and checks prefixes
already seen with a set. `namespaceDeclarations()` compares the node's
declarations with the ancestors' through a map instead of a scan.
- `File.encode` and `Folder.encode` leave `/` unescaped, as the File
object reference lists it among the characters kept
(https://extendscript.docsforadobe.dev/file-system-access/file-object/).
- `exists` is true for a `File` only when the path names something
other than a folder, and for a `Folder` only when it names a folder.
- Fields of the records the app returns are read as own properties, so
a property a script puts on `Object.prototype` does not turn a
successful `open` into a failure.
- `File.encode`, `File.decode`, `File.isEncodingAvailable` and the
`Folder` locations count as file calls and charge the host-call limit.
- On the web the locations are `null` and `File.tempName` names a file
at the root, without asking the platform for a temporary folder.
The saved throw sites of running finally blocks are kept in rising slot
order, so leaving a frame or a block now removes entries from the end of
the list and stops at the first one below the slot. Before, every return
looked at every saved site, so a call made inside many nested finally
blocks took time in proportion to their count.
vectorcraft-js and Check Script took identifier categories from
unicode-general-category 1.1.0, which carries Unicode 16.0, so letters
and marks assigned in Unicode 17.0 (U+088F at the start of a name,
U+1ACF after its first character) were refused. Both lexers now read
general categories from unicode-properties 0.1.4 (Unicode 17.0), which
Cargo.lock already holds. The version is exact because 0.1.5 adds the
Unicode-3.0 license, which is not on the license allowlist. The
Other_ID_Start, Other_ID_Continue and Pattern_Syntax lists are the same
in PropList 17.0.
The exhaustive identifier test now expects the DerivedCoreProperties
17.0 totals (145,916 ID_Start, 149,240 ID_Continue), and new tests read
U+088F and U+1ACF written out and as escapes in both lexers.
Resetting Folder.current for the next run of a named engine now drops the
last run's uncaught exception and $.error first, so memory only they held
no longer makes the reset fail with the heap limit on every later run.
A File an earlier run left open now counts as closed in a later run:
setting its encoding stores it for the next open, and reading the encoding
gives the stored one.
docs/mcp.md: engines stay on the thread that made them, and a
#targetengine line in a file $.evalFile runs makes that call throw a
SyntaxError when it runs.
A `return` inside a finally block discards the pending exception, but the
saved throw site for it stayed in the list of collection roots. The code it
pointed to then stayed live after the function was gone, which could stop a
script with the heap limit when that code came from `Function` or `eval`.
Returning from a frame now drops the saved sites for the slots it leaves.
Follows #6653.
random_seed passes the OS random source's result to random_seed_from, so a test can
give it a known value and check the seed it makes, instead of only reading the source text.
A script whose first lines name an engine with `#targetengine name` (or
`//@targetengine name`) runs in that engine, and a later script that names
it sees the globals and functions earlier runs left, until the engine is
dropped or the session ends. A script without the line, and
`#targetengine main`, still get a new engine for each run.
- A session keeps at most 8 named engines, each with a 64 MiB heap. A run
that goes past the heap ends with the heap limit, and the engine stays
usable. Names are 1 to 64 bytes. The line comes once, in the script
itself, before its code and its #include lines.
- An uncaught error, a limit or script.stop puts the documents back and
keeps the globals the run set. An internal error drops the engine. A run
stopped at a dialog or left paused ends where it was before the engine
is kept. An error in a function an earlier run defined is reported
without a line and column.
- `vc`, `$`, `alert`, `confirm` and `prompt` are made once for each engine
and act for the run that calls them, including copies an earlier run kept
in a global. `vc.args` gives a read-only copy of the calling run's
`args`, and what a run sets on `$` lasts for that run only.
- `script.engines` lists the named engines with their heap, and
`script.engine.drop {name}` drops one. Scripts cannot run either.
- The engines stay on the thread that made them. A session used on
another thread starts there with no named engines, and the old ones are
dropped on their own thread.
- The web build has no named engines: a run that names one other than
`main` ends with an error before any of it runs.
- `Realm::end` ends a run where it is, `Realm::error_source` counts from
the realm's last script, and `HostItem::FrozenGetter` gives a frozen
value each time it is read.
- The script checker lists `#targetengine` as a supported directive.
Docs: docs/mcp.md, docs/target-app-parity.md, docs/gaps.md.
An error a finally block passed on unchanged was reported at the end of
that block, in script.run's report and in the Script Console, because the
block's end raised the error again at a new site. The interpreter now keeps
the site of the exception each finally block runs for, keyed by the stack
slot that holds it, and the block's end throws the exception on from that
site. This holds through nested finally blocks, called functions, resumed
runs and marked host errors. An error the finally block throws is reported
at that throw, and one its return, break or continue discards is not
reported.
Each realm seeded Math.random from std's RandomState. On
wasm32-unknown-unknown its keys come from stack and heap addresses,
which are the same on every page load, so scripts in the web build
drew the same sequence each time the page opened.
The seed now comes from getrandom (crypto.getRandomValues in the
browser, as crates/pdf/src/encrypt.rs already does), with RandomState
kept as the fallback when it fails.
BFlat