fix: address self-review findings
This commit is contained in:
Matt Van Horn
+194
-1
@@ -8,6 +8,8 @@ skin. Use ``--all --baseline`` to skip those documented legacy files.
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import argparse
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import re
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import sys
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from dataclasses import dataclass, field
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from html.parser import HTMLParser
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from pathlib import Path
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@@ -50,6 +52,197 @@ ALLOWED_FONTS = {
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CSS_FONT_KEYWORDS = {"inherit", "initial", "revert", "revert-layer", "unset"}
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@dataclass
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class SvgTextElement:
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tag: str
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element_id: str | None
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line: int
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offset: int
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text: list[str] = field(default_factory=list)
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@dataclass
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class SvgElement:
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attrs: dict[str, str | None]
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line: int
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offset: int
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content_depth: int
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first_child: str | None = None
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ids: set[str] = field(default_factory=set)
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bare_id_locations: list[tuple[int, int]] = field(default_factory=list)
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titles: list[SvgTextElement] = field(default_factory=list)
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descriptions: list[SvgTextElement] = field(default_factory=list)
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class AccessibleSvgParser(HTMLParser):
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"""Collect accessible-name data without rendering or executing HTML.
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Trust boundary: input files are untrusted source text. ``HTMLParser`` only
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tokenizes that text; this linter never evaluates scripts, fetches URLs, or
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opens referenced resources.
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"""
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def __init__(self, text):
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super().__init__(convert_charrefs=True)
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self.line_offsets = [0]
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self.line_offsets.extend(
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match.end() for match in re.finditer(r"\n", text)
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)
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self.element_stack = []
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self.svg_stack = []
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self.svgs = []
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self.open_text = []
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def source_offset(self):
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line, column = self.getpos()
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return self.line_offsets[line - 1] + column
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def handle_starttag(self, tag, attrs):
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tag = tag.casefold()
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attr_map = {name.casefold(): value for name, value in attrs}
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offset = self.source_offset()
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line, _column = self.getpos()
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if self.svg_stack:
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parent = self.svg_stack[-1]
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if len(self.element_stack) == parent.content_depth:
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if parent.first_child is None:
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parent.first_child = tag
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element_id = attr_map.get("id")
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if element_id:
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for svg in self.svg_stack:
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svg.ids.add(element_id)
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if element_id in {"title", "desc"}:
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svg.bare_id_locations.append((line, offset))
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if tag == "svg":
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svg = SvgElement(
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attrs=attr_map,
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line=line,
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offset=offset,
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content_depth=len(self.element_stack) + 1,
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)
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self.svgs.append(svg)
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self.svg_stack.append(svg)
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elif tag in {"title", "desc"} and self.svg_stack:
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svg = self.svg_stack[-1]
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if len(self.element_stack) == svg.content_depth:
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element = SvgTextElement(
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tag=tag,
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element_id=attr_map.get("id"),
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line=line,
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offset=offset,
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)
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if tag == "title":
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svg.titles.append(element)
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else:
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svg.descriptions.append(element)
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self.open_text.append(element)
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self.element_stack.append(tag)
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def handle_startendtag(self, tag, attrs):
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self.handle_starttag(tag, attrs)
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self.handle_endtag(tag)
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def handle_endtag(self, tag):
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tag = tag.casefold()
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for index in range(len(self.open_text) - 1, -1, -1):
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if self.open_text[index].tag == tag:
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del self.open_text[index]
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break
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if tag == "svg" and self.svg_stack:
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self.svg_stack.pop()
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for index in range(len(self.element_stack) - 1, -1, -1):
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if self.element_stack[index] == tag:
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del self.element_stack[index:]
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break
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def handle_data(self, data):
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for element in self.open_text:
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element.text.append(data)
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def lint_accessible_svgs(text):
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parser = AccessibleSvgParser(text)
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parser.feed(text)
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parser.close()
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findings = []
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def add(line, offset, message):
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findings.append((line, offset, "a11y", message))
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for svg in parser.svgs:
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aria_hidden = (svg.attrs.get("aria-hidden") or "").casefold()
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if aria_hidden == "true":
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continue
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if (svg.attrs.get("role") or "").casefold() != "img":
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add(svg.line, svg.offset, 'diagram <svg> must carry role="img"')
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labelled_by = (svg.attrs.get("aria-labelledby") or "").split()
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if not labelled_by:
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add(
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svg.line,
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svg.offset,
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"aria-labelledby must name the <title> and <desc>",
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)
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else:
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missing_ids = [
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element_id for element_id in labelled_by if element_id not in svg.ids
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]
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if missing_ids:
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add(
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svg.line,
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svg.offset,
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"aria-labelledby references missing id(s): "
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+ ", ".join(missing_ids),
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)
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title = svg.titles[0] if svg.titles else None
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description = svg.descriptions[0] if svg.descriptions else None
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if title is None:
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add(svg.line, svg.offset, "diagram <svg> must contain a <title>")
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else:
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if svg.first_child != "title":
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add(
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title.line,
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title.offset,
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"<title> must be the first child element of <svg>",
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)
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if not "".join(title.text).strip():
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add(title.line, title.offset, "<title> must not be empty")
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if description is None:
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add(svg.line, svg.offset, "diagram <svg> must contain a <desc>")
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elif not "".join(description.text).strip():
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add(description.line, description.offset, "<desc> must not be empty")
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title_id = title.element_id if title else None
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description_id = description.element_id if description else None
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if svg.bare_id_locations:
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line, offset = svg.bare_id_locations[0]
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add(
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line,
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offset,
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'bare id="title" and id="desc" are not allowed',
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)
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if (
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labelled_by
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and (title_id not in labelled_by or description_id not in labelled_by)
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):
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add(
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svg.line,
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svg.offset,
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"aria-labelledby must name the <title> and <desc> IDs",
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)
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return findings
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def normalize_hex(value):
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value = value.lower()
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if len(value) == 4:
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@@ -115,7 +308,7 @@ def named_families(value):
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def lint_text(text, colors, rgb_triplets):
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findings = []
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findings = lint_accessible_svgs(text)
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def add(offset, category, message):
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findings.append((line_number(text, offset), offset, category, message))
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