**Summary**
Eliminate historical "idiosyncracies" of `table.metadata.text_as_html`
HTML introduced by `partition_xlsx()`. Produce minified `.text_as_html`
consistent with that formed by chunking.
**Additional Context**
- XLSX `.text_as_html` is minified (no extra whitespace or thead, tbody,
tfoot elements).
- `table.text` is clean-concatenated-text (CCT) of table.
---------
Co-authored-by: scanny <scanny@users.noreply.github.com>
**Summary**
Initial attempts to incrementally refactor `partition_email()` into
shape to allow pluggable partitioning quickly became too complex for
ready code-review. Prepare separate rewritten module and tests and swap
them out whole.
**Additional Context**
- Uses the modern stdlib `email` module to reliably accomplish several
manual decoding steps in the legacy code.
- Remove obsolete email-specific element-types which were replaced 18
months or so ago with email-specific metadata fields for things like Cc:
addresses, subject, etc.
- Remove accepting an email as `text: str` because MIME-email is
inherently a binary format which can and often does contain multiple and
contradictory character-encodings.
- Remove `encoding` parameters as it is now unused. An email file is not
a text file and as such does not have a single overall encoding.
Character encoding is specified individually for each MIME-part within
the message and often varies from one part to another in the same
message.
- Remove the need for a caller to specify `attachment_partitioner`.
There is only one reasonable choice for this which is
`auto.partition()`, consistent with the same interface and operation in
`partition_msg()`.
- Fixes#3671 along the way by silently skipping attachments with a
file-type for which there is no partitioner.
- Substantially extend the test-suite to cover multiple
transport-encoding/charset combinations.
---------
Co-authored-by: ryannikolaidis <1208590+ryannikolaidis@users.noreply.github.com>
Co-authored-by: scanny <scanny@users.noreply.github.com>
This PR addresses issue #3659 by adding an optional `language` parameter
to the `OCRAgentGoogleVision` class constructor.
This parameter serves as a "language hint" for the
`document_text_detection` method in the `ImageAnnotatorClient`. For more
information on language hints, refer to the [Google Cloud Vision
documentation](https://cloud.google.com/vision/docs/languages).
**Default Behavior**:
The language parameter defaults to None, allowing Google Cloud Vision to
auto-detect the language, as recommended in their documentation.
**Purpose**:
This change is necessary because the `OCRAgent`'s `get_instance` method
expects all `OCRAgent`s to include a language parameter in their
constructors.
**Context on Issue:**
When trying to parse a PDF with
`OCR_AGENT=unstructured.partition.utils.ocr_models.google_vision_ocr.OCRAgentGoogleVision`,
an error occurs in the `get_instance` method. The method expects a
`language` parameter, which the current `OCRAgentGoogleVision`
constructor does not support, leading to a positional argument error.
---------
Co-authored-by: Christine Straub <christinemstraub@gmail.com>
**Summary**
Remove double-decoration from EML and MSG.
**Additional Context**
- These needed to wait to the end because `partition_email()` and
`partition_msg()` can use any other partitioner for one of their
attachments.
---------
Co-authored-by: ryannikolaidis <1208590+ryannikolaidis@users.noreply.github.com>
Co-authored-by: scanny <scanny@users.noreply.github.com>
**Summary**
Install new `@apply_metadata()` on TXT.
**Additional Context**
- Both EML and MSG delegate to both HTML and TXT to partition the
message-body, depending on which MIME-part body payload is selected
(`text/plain` or `text/html`). This PR prepares the way to remove
decorators from EML and MSG in the next PR.
---------
Co-authored-by: ryannikolaidis <1208590+ryannikolaidis@users.noreply.github.com>
Co-authored-by: scanny <scanny@users.noreply.github.com>
**Summary**
Install new `@apply_metadata()` on HTML and remove decorators from
delegating partitioners EPUB, MD, ORG, RST, and RTF.
**Additional Context**
- All five of these delegating partitioners delegate to
`partition_html()` so they're something of a matched set. EML and MSG
also partially delegate to HTML but that's a harder problem (they also
delegate to all other partitioners for attachments) that we'll address a
couple PRs later .
- Replace use of `@process_metadata()` and
`@add_metadata_with_filetype()` decorators with `@apply_metadata()` on
`partition_html()`.
- Remove all decorators from delegating partitioners; this removes the
"double-decorating".
**Summary**
Install new `@apply_metadata()` on PPTX, TSV, XLSX, and XML and remove
decoration from PPT.
**Additional Context**
- Alphabetical order turns out to be hard, so this is the remaining
"easy" delegating partitioner and the remaining principal partitioners.
- Replace use of `@process_metadata()` and
`@add_metadata_with_filetype()` decorators with `@apply_metadata()` on
principal partitioners (those that do not delegate to other
partitioners.
- Remove all decorators from delegating partitioners (PPT in this case);
this removes the "double-decorating".
**Summary**
Install new `@apply_metadata()` on CSV and DOCX and remove decoration
from DOC and ODT.
**Additional Context**
- Working in alphabetical order and keeping PR size manageable, replace
use of `@process_metadata()` and `@add_metadata_with_filetype()`
decorators with `@apply_metadata()` on principal partitioners (those
that do not delegate to other partitioners.
- Remove all decorators from delegating partitioners (DOC and ODT in
this case); this removes the "double-decorating".
**Summary**
Refine `@apply_metadata()` replacement decorator. Note it has not been
installed yet.
- Apply `metadata_last_modified` arg with the `@apply_metadata()`
decorator. No need for redundant processing in each partitioner.
- Add "unique-ify" step to fix any cases where the same `Element` or
`ElementMetadata` instance was used more than once in the element
stream. This prevents unexpected "multi-mutation" in downstream
processes.
- Apply "global" metadata items before computing hash-ids. In
particular, `.metadata.filename` is used in the hash computation and
will produce different results if that's not already settled.
- Compute hash-ids _before_ computing `.metadata.parent_id`. This
removes the need for mapping UUID element-ids to their hash counterpart
and doing a fixup of `.parent_id` after applying hash-ids to elements.
**Additional Context**
- The `@apply_metadata()` decorator replaces the four metadata-related
decorators: `@process_metadata()`, `@add_metadata_with_filetype()`,
`@add_metadata()`, and `@add_filetype()`.
- It will be installed on each partitioner in a series of following PRs.
This is a fix for this
[bug](https://github.com/Unstructured-IO/unstructured/issues/3674), auto partition fails on text files which are empty or contain only whitespaces
Inference of .txt file type fails if the file has only whitespaces.
To Reproduce:
```
from tempfile import NamedTemporaryFile
from unstructured.partition.auto import partition
with NamedTemporaryFile(mode="w", suffix=".txt") as f:
f.write(" \n")
f.seek(0)
elements = partition(filename=f.name)
```
**Summary**
In preparation for pluggable auto-partitioners, add a new metadata
decorator to replace the four existing ones.
**Additional Context**
"Global" metadata items, those applied to all element on all
partitioners, are applied using a decorator.
Currently there are four decorators where there only needs to be one.
Consolidate those into a single metadata decorator.
One or two additional behaviors of the new decorator will allow us to
remove decorators from delegating partitioners which is a prerequisite
for pluggable auto-partitioners.
**Summary**
Remove unused `include_metadata` parameter.
**Additional Context**
- The `include_metadata` parameter was originally added circa v0.7.12 as
a mechanism for avoiding the "double-decorating" problem on delegating
partitioners.
- It turns out it doesn't fully address that problem, is now unused, and
is unnecessary for the solution we'll be adding as part of pluggable
partitioners.
- Remove the unnecessary complexity introduced by this unused parameter.
**Summary**
Step 2 in prep for pluggable auto-partitioners, remove `regex_metadata`
field from `ElementMetadata`.
**Additional Context**
- "regex-metadata" was an experimental feature that didn't pan out.
- It's implemented by one of the post-partitioning metadata decorators,
so get rid of it as part of the cleanup before consolidating those
decorators.
Wrap the `shared.PartitionParameters` usage with
`operations.PartitionRequest`. This syntax has been deprecated since
v0.23.0 of the SDK, and will be unsupported in v0.26.0.
**Summary**
In preparation for pluggable auto-partitioners simplify metadata as
discussed.
**Additional Context**
- Pluggable auto-partitioners requires partitioners to have a consistent
call signature. An arbitrary partitioner provided at runtime needs to
have a call signature that is known and consistent. Basically
`partition_x(filename, *, file, **kwargs)`.
- The current `auto.partition()` is highly coupled to each distinct
file-type partitioner, deciding which arguments to forward to each.
- This is driven by the existence of "delegating" partitioners, those
that convert their file-type and then call a second partitioner to do
the actual partitioning. Both the delegating and proxy partitioners are
decorated with metadata-post-processing decorators and those decorators
are not idempotent. We call the situation where those decorators would
run twice "double-decorating". For example, EPUB converts to HTML and
calls `partition_html()` and both `partition_epub()` and
`partition_html()` are decorated.
- The way double-decorating has been avoided in the past is to avoid
sending the arguments the metadata decorators are sensitive to to the
proxy partitioner. This is very obscure, complex to reason about,
error-prone, and just overall not a viable strategy. The better solution
is to not decorate delegating partitioners and let the proxy partitioner
handle all the metadata.
- This first step in preparation for that is part of simplifying the
metadata processing by removing unused or unwanted legacy parameters.
- `date_from_file_object` is a misnomer because a file-object never
contains last-modified data.
- It can never produce useful results in the API where last-modified
information must be provided by `metadata_last_modified`.
- It is an undocumented parameter so not in use.
- Using it can produce incorrect metadata.
**Summary**
In preparation for consolidating post-partitioning metadata decorators,
extract `partition.common` module into a sub-package (directory) and
extract `partition.common.metadata` module to house metadata-specific
object shared by partitioners.
**Additional Context**
- This new module will be the home of the new consolidated metadata
decorator.
- The consolidated decorator is a step toward removing post-processing
decorators from _delegating_ partitioners. A delegating partitioner is
one that convert its file to a different format and "delegates" actual
partitioning to the partitioner for that target format. 10 of the 20
partitioners are delegating partitioners.
- Removing decorators from delegating partitioners will allow us to
avoid "double-decorating", i.e. running those decorators twice, once on
the principal partitioner and again on the proxy partitioner.
- This will allow us to send `**kwargs` to either partitioner, removing
the knowledge of which arguments to send for each file-type from
auto-partition.
- And this will allow pluggable auto-partitioners which all have a
`partition_x(filename, *, file, **kwargs) -> list[Element]` interface.
This PR enhances `pdfminer` image cleanup process by repositioning the
duplicate image removal step. It optimizes the removal of duplicated
pdfminer images by performing the cleanup before merging elements,
rather than after. This improvement reduces execution time and enhances
the overall processing speed of PDF documents.
---------
Co-authored-by: Yao You <theyaoyou@gmail.com>
This PR implements splitting of `pdfminer` elements (`groups of text
chunks`) into smaller bounding boxes (`text lines`). This implementation
prevents loss of information from the object detection model and
facilitates more effective removal of duplicated `pdfminer` text. This
PR also addresses #3430.
---------
Co-authored-by: ryannikolaidis <1208590+ryannikolaidis@users.noreply.github.com>
Co-authored-by: christinestraub <christinestraub@users.noreply.github.com>
- Remove constraint pins for `Office365-REST-Python-Client`,
`weaviate-client`, and `platformdirs`. Removing the pin for `Office365`
brought to light some bugs in the Onedrive connector, so some changes
were also made to
`unstructured/ingest/v2/processes/connectors/onedrive.py`.
- Also, as part of updating dependencies `unstructured-client` was
updated to `0.25.8`, which introduced a new default for the `strategy`
param and required updating a test fixture.
- The `hubspot.sh` integration test was failing and is now ignored in CI
with this PR per discussion with @rbiseck3.
May be easiest to review commit-by-commit.
This PR vectorizes the computation of element overlap to speed up
deduplication process of extracted elements.
## test
This PR adds unit test to the new vectorized IOU and subregion
computation functions.
In addition, running partition on large files with many elements like
this slide:
[002489.pdf](https://github.com/user-attachments/files/16823176/002489.pdf)
shows a reduction of runtime from around 15min on the main branch to
less than 4min with this branch.
Profiling results show that the new implementation greatly reduces the
time cost of computation and now most of the time is spend on getting
the coordinates from a list of bboxes.
This PR changes the way the analysis tools can be used:
- by default if `analysis` is set to `True` in `partition_pdf` and the
strategy is resolved to `hi_res`:
- for each file 4 layout dumps are produced and saved as JSON files
(`object_detection`, `extracted`, `ocr`, `final`) - similar way to the
current `object_detection` dump
- the drawing functions/classes now accept these dumps accordingly
instead of the internal classes instances (like `TextRegion`,
`DocumentLayout`
- it makes it possible to use the lightweight JSON files to render the
bboxes of a given file after the partition is done
- `_partition_pdf_or_image_local` has been refactored and most of the
analysis code is now encapsulated in `save_analysis_artifiacts` function
- to do this, helper function `render_bboxes_for_file` is added
<img width="338" alt="Screenshot 2024-08-28 at 14 37 56"
src="https://github.com/user-attachments/assets/10b6fbbd-7824-448d-8c11-52fc1b1b0dd0">
**Summary**
Eliminate historical "idiosyncracies" of `table.metadata.text_as_html`
HTML introduced by `partition_docx()`. Produce minified `.text_as_html`
consistent with that formed by chunking.
**Additional Context**
- nested tables appear as their extracted text in the parent cell (no
nested `<table>` elements in `.text_as_html`).
- DOCX `.text_as_html` is minified (no extra whitespace or thead, tbody,
tfoot elements).
**Summary**
Use more sophisticated algorithm for splitting oversized `Table`
elements into `TableChunk` elements during chunking to ensure element
text and HTML are "synchronized" and HTML is always parseable.
**Additional Context**
Table splitting now has the following characteristics:
- `TableChunk.metadata.text_as_html` is always a parseable HTML
`<table>` subtree.
- `TableChunk.text` is always the text in the HTML version of the table
fragment in `.metadata.text_as_html`. Text and HTML are "synchronized".
- The table is divided at a whole-row boundary whenever possible.
- A row is broken at an even-cell boundary when a single row is larger
than the chunking window.
- A cell is broken at an even-word boundary when a single cell is larger
than the chunking window.
- `.text_as_html` is "minified", removing all extraneous whitespace and
unneeded elements or attributes. This maximizes the semantic "density"
of each chunk.
This PR reverts `pytesseract` dependency to `unstructured.pytesseract`
fork due to the unavailability of some recent release versions of
`pytesseract` on PyPI.
This PR also addresses an issue encountered during the publication of
`unstructured==0.15.4` to PyPI. The error was due to the fact that PyPI
does not allow direct dependencies from Version Control System URLs like
GitHub in the `install_requires` or `extras_require` sections of the
`setup.py` file.
As described in #3381, some clients, perhaps including Adobe PDF
Converter, map JPEG images to the invalid `image/jpg` MIME-type. Prior
to v1.0.0, `python-pptx` would not load these images, which caused image
extraction to fail.
Update the `python-pptx` dependency to `v1.0.1` or above to ensure this
upstream fix is always available.
Fixes: #3381
Update partition_eml and partition_msg to capture cc, bcc, and message
id fields.
Docs PR: https://github.com/Unstructured-IO/docs/pull/135/files
Testing
```
from unstructured.partition.email import partition_email
from test_unstructured.unit_utils import example_doc_path
elements = partition_email(filename=example_doc_path("eml/fake-email-header.eml"), include_headers=True)
print(elements)
elements[0].metadata.to_dict()
```
Note to reviewers:
Tests in `test_unstructured/partition/test_email.py` were refactored and
rearranged to group similar tests together, so it will be easiest to
review those changes commit by commit.
---------
Co-authored-by: ryannikolaidis <1208590+ryannikolaidis@users.noreply.github.com>
Co-authored-by: Coniferish <Coniferish@users.noreply.github.com>
# Description:
Passing `max_pages` argument allows rejecting pdf files which exceeds
this page number limit while `high_res` strategy is chosen. By default
it will allow parsing pdf files with unlimited number of pages.
# Testing:
```python
from unstructured.partition.auto import partition
elements = partition(filename="unstructured/example-docs/pdf/reliance.pdf", strategy='hi_res') # should pass
elements = partition(filename="unstructured/example-docs/pdf/reliance.pdf", strategy='hi_res', max_pages=4) # should pass
elements = partition(filename="unstructured/example-docs/pdf/reliance.pdf", strategy='hi_res', max_pages=2) # should raise PdfMaxPagesExceededError
```
**Summary**
A DOC, PPT, or XLS file sent to partition() as a file-like object is
misidentified as a MSG file and raises an exception in python-oxmsg
(which is used to process MSG files).
**Fix**
DOC, PPT, XLS, and MSG are all Microsoft OLE-based files, aka. Compound
File Binary Format (CFBF). These can be reliably distinguished by
inspecting magic bytes in certain locations. `libmagic` is unreliable at
this or doesn't try, reporting the generic `"application/x-ole-storage"`
which corresponds to the "container" CFBF format (vaguely like a
Microsoft Zip format) that all these document types are stored in.
Unconditionally use `filetype.guess_mime()` provided by the `filetype`
package that is part of the base unstructured install. Unlike
`libmagic`, this package reliably detects the distinguished MIME-type
(e.g. `"application/msword"`) for OLE file subtypes.
Fixes#3364
**Summary**
In preparation for fixing a cluster of bugs with automatic file-type
detection and paving the way for some reliability improvements, refactor
`unstructured.file_utils.filetype` module and improve thoroughness of
tests.
**Additional Context**
Factor type-recognition process into three distinct strategies that are
attempted in sequence. Attempted in order of preference,
type-recognition falls to the next strategy when the one before it is
not applicable or cannot determine the file-type. This provides a clear
basis for organizing the code and tests at the top level.
Consolidate the existing tests around these strategies, adding
additional cases to achieve better coverage.
Several bugs were uncovered in the process. Small ones were just fixed,
bigger ones will be remedied in following PRs.
**Summary**
Replace conditional explicit import of partitioner modules in
`.partition.auto` with the new `_PartitionerLoader` class. This avoids
unbound variable warnings and is much less noisy.
`_PartitionerLoader` makes use of the new `FileType` property
`.importable_package_dependencies` to determine whether all required
packages are importable before dispatching the file to its partitioner.
It uses `FileType.extra_name` to form a helpful error message when a
dependency is not installed, so the caller knows which `pip install`
extra to specify to remedy the error.
`PartitionerLoader` uses the `FileType` properties
`.partitioner_module_qname` and `partitioner_function_name` to load
the partitioner once its dependencies are verified. Loaded partitioners
are cached with module lifetime scope for efficiency.
### Summary
Currently, the email partitioner removes only `=\n` characters during
the clearing process. However, email content sometimes contains `=\r\n`
characters, especially when read from file-like objects such as
`SpooledTemporaryFile` (the file type used in our API). This PR updates
the email partitioner to remove both `=\n` and `=\r\n` characters during
the clearing process.
### Testing
```
filename = "example-docs/eml/family-day.eml"
elements = partition_email(
filename=filename,
)
print(f"From filename: {elements[3].text}")
with open(filename, "rb") as test_file:
spooled_temp_file = tempfile.SpooledTemporaryFile()
spooled_temp_file.write(test_file.read())
spooled_temp_file.seek(0)
elements = partition_email(file=spooled_temp_file)
print(f"From spooled_temp_file: {elements[3].text}")
```
**Results:**
- on `main`
```
From filename: Make sure to RSVP!
From spooled_temp_file: Make sure to = RSVP!
```
- on `PR`
```
From filename: Make sure to RSVP!
From spooled_temp_file: Make sure to RSVP!
```
This PR aims to improve the organization and readability of our example
documents used in unit tests, specifically focusing on PDF and image
files.
### Summary
- Created two new subdirectories in the `example-docs` folder:
- `pdf/`: for all PDF example files
- `img/`: for all image example files
- Moved relevant PDF files from `example-docs/` to `example-docs/pdf/`
- Moved relevant image files from `example-docs/` to `example-docs/img/`
- Updated file paths in affected unit & ingest tests to reflect the new
directory structure
### Testing
All unit & ingest tests should be updated and verified to work with the
new file structure.
## Notes
Other file types (e.g., office documents, HTML files) remain in the root
of `example-docs/` for now.
## Next Steps
Consider similar reorganization for other file types if this structure
proves to be beneficial.
---------
Co-authored-by: ryannikolaidis <1208590+ryannikolaidis@users.noreply.github.com>
Co-authored-by: christinestraub <christinestraub@users.noreply.github.com>
**Summary**
Elaborate the `FileType` enum to be a complete descriptor of file-types.
Add methods to allow `STR_TO_FILETYPE`, `EXT_TO_FILETYPE` and
`FILETYPE_TO_MIMETYPE` mappings to be replaced, removing those redundant
and noisy declarations.
In the process, fix some lingering file-type identification and
`.metadata.filetype` errors that had been skipped in the tests.
**Additional Context**
Gathering the various attributes of a file-type into the `FileType` enum
eliminates the duplication inherent in the separate `STR_TO_FILETYPE`
etc. mappings and makes access to those values convenient for callers.
These attributes include what MIME-type a file-type should record in
metadata and what MIME-types and extensions map to that file-type. These
values and others are made available as methods and properties directly
on the `FileType` class and members. Because all attributes are defined
in the `FileType` enum there is no risk of inconsistency across multiple
locations and any changes happen in one and only one place. Further
attributes and methods will be added in later commits to support other
file-type related operations like mapping to a partitioner and verifying
its dependencies are installed.
Closes#3159.
This PR extends language specification capability to `PaddleOCR` in
addition to `TesseractOCR`. Users can now specify OCR languages for both
OCR engines when using `partition_pdf()`.
### Testing
```
os.environ["OCR_AGENT"] = "unstructured.partition.utils.ocr_models.paddle_ocr.OCRAgentPaddle"
elements = partition_pdf(
filename=<file_path>,
strategy=strategy,
languages=["chi_sim"], # chinese - simplified
infer_table_structure=True,
)
```
**Summary**
Replace legacy HTML parser with recursive version that captures all
content and provides flexibility to add new metadata. It's also
substantially faster although that's just a happy side-effect.
**Additional Context**
The prior HTML parsing algorithm that makes up the core of HTML
partitioning was buggy and very difficult to reason about because it did
not conform to the inherently recursive structure of HTML. The new
version retains `lxml` as the performant and reliable base library but
uses `lxml`'s custom element classes to efficiently classify HTML
elements by their behaviors (block-item and inline (phrasing) primarily)
and give those elements the desired partitioning behaviors.
This solves a host of existing problems with content being skipped and
elements (paragraphs) being divided improperly, but also provides a
clear domain model for reasoning about its behavior and reliably
adjusting it to suit our existing and future purposes.
The parser's operation is recursive, closely modeling the recursive
structure of HTML itself. It's behaviors are based on the HTML Standard
and reliably produce proper and explainable results even for novel
cases.
Fixes#2325Fixes#2562Fixes#2675Fixes#3168Fixes#3227Fixes#3228Fixes#3230Fixes#3237Fixes#3245Fixes#3247Fixes#3255Fixes#3309
### BEHAVIOR DIFFERENCES
#### `emphasized_text_tags` encoding is changed:
- `<strong>` is encoded as `"b"` rather than `"strong"`.
- `<em>` is encoded as `"i"` rather than `"em"`.
- `<span>` is no longer recorded in `emphasized_text_tags` (because
without the CSS we can't tell whether it's used for emphasis or if so
what kind).
- nested emphasis (e.g. bold+italic) is encoded as multiple characters
("bi").
- `emphasized_text_contents` is broken on emphasis-change boundaries,
like:
```html
`<p>foo <b>bar <i>baz</i> bada</b> bing</p>`
```
produces:
```json
{
"emphasized_text_contents": ["bar", "baz", "bada"],
"emphasized_text_tags": ["b", "bi", "b"]
}
```
whereas previously it would have produced:
```json
{
"emphasized_text_contents": ["bar baz bada", "baz"],
"emphasized_text_tags": ["b", "i"]
}
```
#### `<pre>` text is preserved as it appears in the html
Except that a leading newline is removed if present (has to be in
position 0 of text). Also, a trailing newline is stripped but only if it
appears in the very last position ([-1]) of the `<pre>` text. Old parser
stripped all leading and trailing whitespace.
Result is that:
```html
<pre>
foo
bar
baz
</pre>
```
parses to `"foo\nbar\nbaz"` which is the same result produced for:
```html
<pre>foo
bar
baz</pre>
```
This equivalence is the same behavior exhibited by a browser, which is
why we did the extra work to make it this way.
#### Whitespace normalization
Leading and trailing whitespace are removed from element text, just as
it is removed in the browser. Runs of whitespace within the element text
are reduced to a single space character (like in the browser). Note this
means that `\t`, `\n`, and ` ` are replaced with a regular space
character. All text derived from elements is whitespace normalized
except the text within a `<pre>` tag. Any leading or trailing newline is
trimmed from `<pre>` element text; all other whitespace is preserved
just as it appeared in the HTML source.
#### `link_start_indexes` metadata is no longer captured. Rationale:
- It was frequently wrong, often `-1`.
- It was deprecated but then added back in a community PR.
- Maintaining it across any possible downstream transformations (e.g.
chunking) would be expensive and almost certainly lead to wrong values
as distant code evolves.
- It is complex to compute and recompute when whitespace is normalized,
adding substantial complexity to the code and reducing readability and
maintainability
#### `<br/>` element is replaced with a single newline (`"\n"`)
but that is usually replaced with a space in `Element.text` when it is
normalized. The newline is preserved within a `<pre>` element.
- Related: _No paragraph-break on `<br/><br/>`_
#### Empty `h1..h6` elements are dropped.
HTML heading elements (`<h1..h6>`) are "skipped" (do not generate a
`Title` element) when they contain no text or contain only whitespace.
---------
Co-authored-by: scanny <scanny@users.noreply.github.com>
**Note**
This refines the new HTML parser but _does not install it_. This is why
no changes to ingest test expectations or other unit-tests are required
here. Installing the new parser will happen in the next PR #3218.
**Summary**
The initial version of the parser (purposely) raised on a block element
nested inside a phrasing element. While such nesting is not valid
according to the HTML Standard, it is accepted by the browser and does
happen in the wild.
The refinements here handle this situation similarly to how the browser
does, breaking phrasing at the block element boundaries and starting it
up again after the block element.
Unfortunately this adds complexity to the parser, but it makes the
parser robust against pretty much any HTML we're likely to encounter and
partitions it consistent with how it would be rendered in the browser.
**Summary**
In preparation for further work on auto-partitioning (`partition()`),
improve typing and organize `test_auto.py` by introducing categories.
