A field's own (partial) name can't contain a period (ISO 32000-2
§12.7.4.2), so Prepare a form refused MASTER.first. Acrobat reads such a
name as a full name: the field `first` under a parent field `MASTER`.
- add_field: a dotted name makes or joins the parent fields it names.
- set_props: a dotted name is the full name and moves the field there,
copying what it inherited onto it first; a plain name still renames
the field within its parent. Either way the new full name may not be
taken by, or hold or sit inside, another field.
- A field joining an existing parent doesn't take its Ff or Q.
- Field Properties and the Prepare a form name tags show the full name
instead of the last part.
- Names are capped at 32 parts; empty parts are refused.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Extraction walked the name tree again with a fresh key budget, so keys
the listing had left out could fill it and a listed embedded file came
back as not found. The lookup compares each key with the one wanted and
keeps none, so it needs no budget; a key object or /Names array that
several places reference is converted once.
A kept web address or attachment text spent only its converted length,
so a long raw value that trimmed short was converted in full for every
entry sharing it. A kept conversion now spends the longer of its raw
and converted lengths.
The embedded-files name tree copied every key, and an attachment
without a file name copied its key again as the name, so many entries
sharing one long key string multiplied it. Keys, and a key kept again
as the name, now spend the 16 MiB link and attachment text budget; an
embedded file whose key does not fit is not listed.
An annotation attachment's /Contents was read and charged to the text
budget before the file specification's /UF or /F, which then named the
attachment, so the discarded text could leave a later web address
unlisted. /Contents is now read only when neither name is there.
A web address or attachment text that converted to more than the budget
left spent nothing, so every link or attachment sharing it converted it
again. A conversion that comes out too long now spends the raw length,
and so does attachment text that trims to nothing.
The link and attachment listings copied a link's web address and an
attachment's name and description for every annotation or name-tree
entry, so many entries sharing one long string multiplied it in
memory. Together they keep at most 16 MiB of that text, and a string
past what is left is not converted. A link past it lists as a URI
action without its address, an attachment under its generic name
without a description.
The annotation listing skipped a repeated /Annots entry by its raw
reference, so an indirect object holding only a reference to a link
listed that link a second time. Entries and page arrays are now told
apart by the object their reference chain ends at. The lopdf reader
reported the first object of a chain, because lopdf's get_object
already follows it; it now reports the last, as the lazy reader does.
A /Kids array listing one widget many times, or shared by several fields,
built a Widget for every listing, so a small file expanded into fields times
listings widgets. A widget now belongs to the first field that lists it, and a
page widget already owned is not adopted again.
The tests each branch appends to the audit, edit and organize test files are
kept side by side; prune.rs merges cleanly, with the form memo on top of the
budgeted page content.
The JPEG decoder re-sorts and rescans every pending Extended XMP chunk after
each marker, so a file of many small chunks cost time quadratic in their
number before any pixel limit applied. Turning a photo upright now counts
the chunks first and leaves a JPEG with more than 1024 as it is.
A one-pixel GIF on a huge logical screen decodes to a canvas that size,
which the conversion then copied before splitting it into colour and alpha,
so a few bytes could hold over a gigabyte. Screens past 16 Mpx are refused
before decoding, and the decoded canvas is converted without a copy.
A TIFF's pages were each capped at 2 GiB but all kept in memory until
embedded, so many small directories sharing one compressed strip could ask
for many times that; embedding one image also decoded every page. The pages
of one TIFF are now refused past 4 GiB together, and image_xobject reads
only the first page.
The redaction audit read each page's text through text_lines, which walked
the whole page tree again for every page (quadratic in the page count) and
let /ActualText replace the glyphs, so an empty or substitute ActualText hid
covered text from the audit. Edit gains glyph_text_lines, which reads the
page dictionary it is given and ignores ActualText; the audit uses it.
Text extraction copies a ToUnicode destination for every glyph showing its
code, and the page's total text was not bounded, so a small page could expand
into gigabytes. One page's extraction (its forms included) stops with an error
past 16 MiB of text.
Past the marked-content depth budget the number of open sequences is unknown,
and the mark on top was appended with none of them closed, so the page's own
optional-content scopes (possibly hidden) could hide a redaction box, a
header or a watermark. Placing on top of such a page is now refused before
anything changes; behind it is still possible.
Removing flattened widgets from the field tree recursed into every /Kids
entry with only a depth limit, so a node listing its child twice per level
(or itself) made the walk exponential. Each node's answer is now remembered;
a node met again while it is still being visited survives, as it did when
the depth limit stopped a cycle.
Writing an added text item re-wrapped the whole text inside the loop over its
lines to learn the line count, so multiline text cost time and temporary
memory quadratic in its length. The wrapped lines are computed once.
Each candidate attribute match searched the whole packet before it for the
last < and >, so a long text node repeating the attribute name cost time
quadratic in the packet size (up to the 16 MiB decode cap). The scan now
keeps the last < and > as it moves forward.
The pruner decoded and walked a form XObject again on every Do that drew
it, so a form drawing itself a few times per level was analysed
exponentially often within the depth limit. Forms are now remembered with
the resources owner they were drawn against, and a repeat records nothing
new.
Looking up a named destination and listing attachments in a source's name
trees followed every /Kids entry with only a depth limit, so a node listing
the same child twice per level made the walk (and the attachment list)
exponential in the depth. Both walks now skip a node already read.
Fixing up copied annotations cloned the whole source-to-destination map for
every non-GoTo action and dropped the copies it made, so many annotations
cost quadratic memory and time and an object shared by their actions was
copied once per action. The copier now lends its map to the action copy and
takes it back with the new entries.
Renaming a colliding field tried Name-1, Name-2, ... from 1 every time, so
many fields of one name cost a quadratic number of attempts during import,
combine and their conflict previews. Taken names only grow, so the search
now resumes after the last suffix handed out for that name; the result is
still the first free variant.
Each imported top-level field was checked against every field already in
/AcroForm /Fields before it was appended, so a page with many distinct
widget fields cost time quadratic in their number. Membership is now kept
in a set beside the list.
Adds a test-only work counter to the crate, so tests can bound the work a
hostile document causes without timing it.
A section naming an /XRefStm that a newer section had already read
skipped the stream entirely, so an entry in its own table that
disagreed with the stream was no longer recorded in xref_oddities.
Signature validation reads those records to refuse an appended section
another reader could follow. The reader keeps each hybrid stream's
entries (up to MAX_XREF_OBJECTS in all) and compares every later
naming section's table with them, without decoding the stream again.
