fix(frontmatter): write a value a YAML reader reads back, and read both forms

K3-22. SPEC SS 11 point 1: "Every non-reserved `.md` file in the tree
contains a parseable YAML frontmatter block." Measured with PyYAML 6.0.3,
okf's own default K2 bundle failed safe_load on 41 of 455 blocks and the
R761 build on 1 of 2 763, every one a block scalar written verbatim.

Block (the profile emitter, every key): a value the K3-19 rule refuses as
plain is written double-quoted, `\` and `"` escaped; every other value keeps
its bytes, and a flow collection or an empty value is written as it stands.
The rule, now `profiles.yaml_block_plain`, agrees with PyYAML on every
top-level value in eleven measured trees (0 refused that it reads verbatim,
0 kept that it does not). Double, never single: 0 values in those trees are
`"`-wrapped and 11 193 are `'`-wrapped.

Flow (`sources`, Door A and Door B, and a run-stated flow value): the pinned
guard refuses ANY quote in a flow mapping (1.3.0, measured), so a leaf PyYAML
needs quoted has no form both read. `yaml_flow_plain` refuses it instead:
`,[]{}`, `?`, a quote, ": ", " #", a trailing `:`, a leading indicator -- a
leading `-` before a non-space excepted, which both readers take. The file
name is checked too, because it is the entry's `title` when the document
declares none. Existing codes: inbox_source_file_unaddressable,
inbox_source_title_unaddressable, source_reference_unquotable,
run_frontmatter_invalid.

Readers: parse_frontmatter, profiles' and structure's copies, and both
read_sources branches unquote a `"`-wrapped value (`\"` and `\\` decoded,
nothing else); `'`-wrapped values are untouched, and structure keeps the
single-quote rule it already had. The flow-mapping split is quote-aware, so
`{ title: "a, b" }` is one pair. The generated SKILL.md header goes through
the same block rule.

TWO K3-19 TESTS MOVED, deliberately: test_run_frontmatter built with
`sources=[{ resource: ...?languageCode=nb, ... }]`, the exact form PyYAML
refused on 2 761 of 2 761 frontmatters of K3-19's flagged build. The two
build tests now write an address without `?`; the flag-grammar test keeps
the `?` address (it only splits), and a new test holds that the build
refuses it with exit 2 and writes nothing.

1753 passed, 1 skipped (OKF_HTML_CORPUS, known). No golden moved.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
This commit is contained in:
Kjell Tore Guttormsen 2026-09-11 11:09:49 +02:00
commit ed0418f228
7 changed files with 288 additions and 79 deletions

View file

@ -65,6 +65,7 @@ from .profiles import (
RESERVED_OKF_TYPE,
SEGMENTED_OKF_V0_2,
BundleProfile,
unquote_scalar,
)
#: The profile whose index policy reads a faceted, per-directory index -- the
@ -432,29 +433,52 @@ def _parse_flow_mappings(value: str) -> list[dict[str, str]] | None:
if not (item.startswith("{") and item.endswith("}")):
return None
pairs: dict[str, str] = {}
for field in item[1:-1].split(","):
# Split where a comma is not inside a `"`-quoted leaf, and unquote the
# leaf: a YAML reader reads `{ title: "a, b" }` as ONE pair (K3-22).
for field in _split_top_level(item[1:-1], "{", "}"):
key, separator, raw = field.partition(":")
if separator:
pairs[key.strip()] = raw.strip()
pairs[key.strip()] = unquote_scalar(raw.strip())
mappings.append(pairs)
return mappings
def _split_top_level(body: str, opener: str, closer: str) -> list[str]:
"""Split on commas that are not inside a `{...}`."""
"""Split on commas that are not inside a `{...}` or a `"`-quoted scalar.
A `"` opens a quoted scalar only where a YAML value can START -- after
`:`, `,`, the opener, or at the beginning -- so a plain value carrying a
`"` in its middle is split exactly as it was before K3-22.
"""
parts: list[str] = []
depth = 0
current: list[str] = []
quoted = escaped = False
previous = ""
for character in body:
current.append(character)
if quoted:
if escaped:
escaped = False
elif character == "\\":
escaped = True
elif character == '"':
quoted = False
previous = character
continue
if character == '"' and previous in ("", ":", ",", opener):
quoted = True
continue
if character == opener:
depth += 1
elif character == closer:
depth -= 1
if character == "," and depth == 0:
current.pop()
parts.append("".join(current))
current = []
continue
current.append(character)
if not character.isspace():
previous = character
parts.append("".join(current))
return [part for part in parts if part.strip()]
@ -550,7 +574,7 @@ def read_sources(lines: Sequence[str]) -> tuple[tuple[Mapping[str, str], ...], b
key, separator, raw = item.partition(":")
if not separator:
return (), True
entries[-1][key.strip()] = raw.strip()
entries[-1][key.strip()] = unquote_scalar(raw.strip())
if not entries:
return (), True
return tuple(entries), True

View file

@ -38,7 +38,16 @@ from .materialize import (
validate_ingested_at,
write_bytes,
)
from .profiles import DEFAULT, BundleProfile, IndexEntry, ProvenancePolicy
from .profiles import (
DEFAULT,
BundleProfile,
IndexEntry,
ProvenancePolicy,
yaml_block_plain,
yaml_flow_collection,
yaml_flow_collection_plain,
yaml_flow_plain,
)
from .segmentation import (
SegmentationPlan,
SegmentEntry,
@ -213,7 +222,7 @@ def render_inbox_concept(
frontmatter[policy.offset_key] = _render_flow_list([str(offset) for offset in segment.span])
if segment.parent_id is not None:
frontmatter["parent"] = segment.parent_id
if segment.description is not None and _yaml_plain(segment.description):
if segment.description is not None and yaml_block_plain(segment.description):
# The SOURCE's words, carried by the plan, and written only where
# they read back verbatim. Absent is the source saying nothing, or
# saying it in a form this line cannot carry -- never a summary
@ -313,9 +322,12 @@ def validate_concept_frontmatter(
SPEC SS 4.1 lets a producer add any key and SS 11 forbids a consumer to
reject one, so the limits here are this package's own and each is a
reader it has to survive: the value is written verbatim on ONE line
because every reader here is line-oriented, which rules out a line break
and -- since `parse_frontmatter` strips -- surrounding whitespace.
reader it has to survive: the value is written on ONE line because every
reader here is line-oriented, which rules out a line break and -- since
`parse_frontmatter` strips -- surrounding whitespace. A scalar goes out
plain where a YAML reader returns it verbatim and double-quoted otherwise;
a flow collection goes out as given, so every leaf in it must be one both a
YAML reader and the guard read back (K3-22).
"""
written = _door_keys(profile)
for key, value in values.items():
@ -336,16 +348,17 @@ def validate_concept_frontmatter(
f"surrounding whitespace, got {value!r}",
code="run_frontmatter_invalid",
)
if yaml_flow_collection(value) and not yaml_flow_collection_plain(value):
raise MaterializationError(
f"frontmatter value for {key!r} is a flow collection a YAML reader and "
"the guard would not both read back as written: a leaf carrying `?`, a "
"quote, ': ', ' #', a trailing `:` or a leading indicator has no flow "
f"form both accept, got {value!r}",
code="run_frontmatter_invalid",
)
return dict(values)
# The characters that would end a YAML flow mapping early, so a path carrying
# one would produce a `sources` list that parses as something other than what
# was written. The guard refuses a quoted scalar inside a flow mapping (1.3.0,
# measured), so escaping is not on the table -- validation is.
_FLOW_TERMINATORS = ",{}[]"
def _provenance_frontmatter(
policy: ProvenancePolicy,
*,
@ -360,22 +373,26 @@ def _provenance_frontmatter(
"which document", the locator answers "where in it", and a consumer is owed
the first even when the second cannot be computed.
"""
bad = [char for char in _FLOW_TERMINATORS if char in source_file]
if bad:
# Validation, never quoting: plain is the one form of a flow-mapping leaf
# that a YAML reader and the guard both read back verbatim -- the guard
# refuses any quote in a flow mapping (1.3.0, measured) -- so a value it
# cannot carry is refused rather than mangled (K3-22). The file name is
# checked too: it is the entry's `title` when the document declares none.
shown = title if title is not None else PurePosixPath(source_file).name
if not yaml_flow_plain(source_file) or (title is None and not yaml_flow_plain(shown)):
raise MaterializationError(
f"source_file {source_file!r} contains {bad[0]!r}, which would end the "
"`sources` flow mapping early; this profile writes an address a "
"consumer can follow, and a path it cannot express is refused rather "
"than mangled",
f"source_file {source_file!r} has no plain form in the `sources` flow "
"mapping that both a YAML reader and the guard read back verbatim; this "
"profile writes an address a consumer can follow, and a path it cannot "
"express is refused rather than mangled",
code="inbox_source_file_unaddressable",
)
if title is not None and not _flow_expressible(title):
if title is not None and not yaml_flow_plain(title):
raise MaterializationError(
f"source title {title!r} cannot be written into the `sources` flow "
"mapping verbatim; refused rather than mangled",
code="inbox_source_title_unaddressable",
)
shown = title if title is not None else PurePosixPath(source_file).name
values = {policy.sources_key: f"[{{ resource: {source_file}, title: {shown} }}]"}
if units is None or span is None:
return values
@ -395,35 +412,6 @@ def _provenance_frontmatter(
return values
def _flow_expressible(value: str) -> bool:
"""Whether `value` survives as a plain scalar inside a flow mapping."""
return bool(value) and not any(char in value for char in f"{_FLOW_TERMINATORS}\n\r")
# What a YAML reader takes as syntax at the START of a plain scalar.
_YAML_INDICATORS = frozenset("-?:,[]{}#&*!|>'\"%@`")
def _yaml_plain(value: str) -> bool:
"""Whether `value` reads back verbatim as a plain scalar in a block mapping.
MEASURED ON R761: 217 of 2 024 first spec points carry `": "`, and PyYAML's
`safe_load` refused exactly those 217 concepts' frontmatter. Decided by
rule rather than by a parser, because this package's one runtime
dependency is the guard -- and over those 2 024 values the rule and PyYAML
agree on every one: 217 refused, 0 refused that PyYAML reads, 0 kept that
it does not.
"""
return (
bool(value)
and value[0] not in _YAML_INDICATORS
and ": " not in value
and " #" not in value
and not value.endswith(":")
and not any(char in value for char in "\t\n\r")
)
def _screened(gate: Gate, value: str | None) -> str | None:
"""A value read from the DOCUMENT and persisted outside its screened body.
@ -462,7 +450,7 @@ def _declared_sources_title(identity: DeclaredIdentity | None, gate: Gate) -> st
candidates.append(identity.title)
for candidate in candidates:
kept = _screened(gate, candidate)
if kept is not None and _flow_expressible(kept):
if kept is not None and yaml_flow_plain(kept):
return kept
return None

View file

@ -29,7 +29,7 @@ from .manifest import (
generated_filename,
load_manifest_bytes,
)
from .profiles import DEFAULT, BundleProfile
from .profiles import DEFAULT, BundleProfile, unquote_scalar, yaml_flow_plain
from .render import render_fenced_block, render_table
_LOGGER = logging.getLogger(__name__)
@ -135,7 +135,10 @@ def parse_frontmatter(path: Path) -> dict[str, str]:
continue
key, sep, value = line.partition(":")
if sep:
frontmatter[key.strip()] = value.strip()
# A `"`-wrapped value is how the emitter writes a scalar a YAML
# reader would refuse plain (K3-22); read back as that reader
# would. A `'`-wrapped one is returned as it stands.
frontmatter[key.strip()] = unquote_scalar(value.strip())
return frontmatter
@ -170,12 +173,6 @@ def _is_ingest_owned(path: Path, manifest_stem: str, *, profile: BundleProfile =
return reference.rsplit("@", 1)[0] == manifest_stem
# The characters that terminate or restructure a YAML flow mapping. `:\s`
# catches a colon that would open a nested key; a colon inside `https://host`
# does not, and stays a plain scalar.
_FLOW_UNSAFE_RE = re.compile(r"[,\[\]{}]|:\s")
def _source_locator(source: Source) -> str:
"""Where a manifest source points, per source type.
@ -238,11 +235,12 @@ def _render_sources(sources: Sequence[Source]) -> str:
for source in sources:
locator = _source_locator(source)
for label, value in (("id", source.id), ("resource", locator)):
if _FLOW_UNSAFE_RE.search(value):
if not yaml_flow_plain(value):
raise MaterializationError(
f"the source {label} {value!r} contains a character that would "
"restructure the `sources` flow mapping (one of `,[]{}` or a "
"colon followed by whitespace) — refusing to emit a provenance "
f"the source {label} {value!r} has no plain form in the `sources` "
"flow mapping that both a YAML reader and the guard read back "
"verbatim (`,[]{}`, `?`, a quote, ': ', ' #', a trailing `:` or a "
"leading YAML indicator) — refusing to emit a provenance "
"record that parses cleanly into something no one wrote",
code="source_reference_unquotable",
)

View file

@ -42,6 +42,159 @@ RESERVED_OKF_TYPE = "verdict"
_TIMESTAMP_FALLBACK_PAIR = frozenset({"timestamp", "generated"})
# --- YAML scalar forms (K3-22) -----------------------------------------------
#
# SPEC SS 11 point 1 requires "a parseable YAML frontmatter block" and SS 4
# names no YAML version and no subset, so the reader a consumer has decides;
# PyYAML is the common one. The forms are decided by RULES here and never by a
# parser -- this package's one runtime dependency is the guard -- and the rules
# are validated against PyYAML in `tests/test_yaml_frontmatter.py`, both error
# directions counted.
# What a YAML reader takes as syntax at the START of a plain scalar.
_YAML_INDICATORS = frozenset("-?:,[]{}#&*!|>'\"%@`")
# What a plain scalar INSIDE a flow mapping may not carry, for one of the two
# readers a `sources` entry has to survive. `,[]{}` end it for both. `?` ends
# it for PyYAML, whose scanner stops a flow plain scalar there, so a URL with a
# query string fails `safe_load`. A quote anywhere is refused by the pinned
# guard, which admits no quoted leaf in a flow mapping (1.3.0, measured). So
# quoting cannot rescue a flow value: plain fails one reader, quoted the other.
_FLOW_UNSAFE = frozenset(",[]{}?'\"")
# A key inside a flow mapping, as the guard's `_KEY_RE` and our readers take it.
_FLOW_KEY = re.compile(r"^[A-Za-z_][A-Za-z0-9_-]*$")
def yaml_block_plain(value: str) -> bool:
"""Whether `value` reads back verbatim as a plain scalar in a block mapping.
MEASURED ON R761 (K3-19): 217 of 2 024 first spec points carry `": "`, and
PyYAML's `safe_load` refused exactly those 217 concepts' frontmatter. K3-22
measured the same rule over every top-level value in eleven trees (the K2
default bundle, the R761 HTML and XML builds, a five-document project, this
repository's examples and fixtures, and five consumer bundles): 0 refused
that PyYAML returns verbatim, 0 kept that it does not. `" #"` is here
although PyYAML does not refuse it: `title: Kap #3` loads, as `Kap`.
"""
return (
bool(value)
and value[0] not in _YAML_INDICATORS
and ": " not in value
and " #" not in value
and not value.endswith(":")
and not any(char in value for char in "\t\n\r")
)
def yaml_flow_plain(value: str) -> bool:
"""Whether `value` reads back verbatim as a plain scalar inside a flow
mapping, for PyYAML AND the pinned guard.
The block rule plus `_FLOW_UNSAFE`, with one exception the block rule does
not make: a leading `-` followed by a non-space is an ordinary character in
a flow mapping for both readers (`del/-utkast.pdf`), and refusing it would
refuse an address both of them read. The block rule keeps refusing it
because it also decides which spec points are written at all (K3-19), and
in a block mapping a refusal only costs a pair of quotes.
"""
if not value or any(char in value for char in _FLOW_UNSAFE):
return False
rest = value[1:] if value[0] == "-" and value[1:2] not in ("", " ", "\t") else value
return yaml_block_plain(rest)
def yaml_flow_collection(value: str) -> bool:
"""Whether `value` is SHAPED as a flow collection (`[...]` or `{...}`).
Structure a producer built -- `source_offset: [0, 4]`, `generated: { by: x,
at: y }` -- is written as it stands; measured over the same eleven trees,
only structural keys carry this shape and no `title` does.
"""
return (value[:1], value[-1:]) in (("[", "]"), ("{", "}"))
def yaml_flow_collection_plain(value: str) -> bool:
"""Whether a flow collection parses, for PyYAML and the guard, into what
was written: one `{ key: leaf, ... }` mapping, or a `[...]` sequence of
such mappings or of scalars, every leaf `yaml_flow_plain`."""
if value[:1] == "{" and value[-1:] == "}":
return _flow_mapping_plain(value)
if not (value[:1] == "[" and value[-1:] == "]"):
return False
items: list[str] = []
depth = 0
current: list[str] = []
for char in value[1:-1]:
depth += {"{": 1, "}": -1}.get(char, 0)
if depth not in (0, 1):
return False
if char == "," and depth == 0:
items.append("".join(current).strip())
current = []
else:
current.append(char)
items.append("".join(current).strip())
if depth != 0:
return False
return all(
_flow_mapping_plain(item) if item[:1] == "{" else yaml_flow_plain(item) for item in items
)
def _flow_mapping_plain(item: str) -> bool:
if not (item[:1] == "{" and item[-1:] == "}"):
return False
inner = item[1:-1].strip()
if not inner:
return False
for entry in inner.split(","):
key, separator, leaf = entry.strip().partition(": ")
if not separator or not _FLOW_KEY.match(key) or not yaml_flow_plain(leaf.strip()):
return False
return True
def quote_scalar(value: str) -> str:
"""`value` as a double-quoted YAML scalar: `\\` and `"` escaped, nothing else.
Double and never single: over every bundle measured, 0 values carry a
surrounding `"` pair and 11 193 a surrounding `'` pair, so a reader that
unquotes `"` changes the meaning of no value already written.
"""
return '"' + value.replace("\\", "\\\\").replace('"', '\\"') + '"'
def unquote_scalar(value: str) -> str:
"""A surrounding `"` pair removed and `\\"` / `\\\\` decoded; else `value`.
The two escapes `quote_scalar` writes are the two decoded. Any other
backslash sequence (`\\n`, `\\t`, `\\x..`, `\\u....`) is kept as written:
a YAML reader would decode it and this reader does not claim to. A
single-quoted value is returned as it stands -- `'1'` stays `'1'`.
"""
if len(value) < 2 or value[0] != '"' or value[-1] != '"':
return value
inner = value[1:-1]
out: list[str] = []
index = 0
while index < len(inner):
char = inner[index]
if char == "\\" and inner[index + 1 : index + 2] in ('"', "\\"):
out.append(inner[index + 1])
index += 2
continue
out.append(char)
index += 1
return "".join(out)
def block_scalar(value: str) -> str:
"""`value` as written after `key: ` in a block mapping: plain where a YAML
reader returns it verbatim, double-quoted otherwise."""
return value if yaml_block_plain(value) else quote_scalar(value)
@dataclass(frozen=True)
class TypeRejection:
"""Why a profile refuses an `okf_type`, for the door to frame and raise.
@ -258,11 +411,18 @@ class FrontmatterSchema:
than trusting insertion order is what makes a regeneration over the
same data byte-identical.
A scalar a YAML reader would refuse or misread as plain is written
double-quoted (K3-22); every other value keeps its bytes. A flow
collection is written as it stands -- its leaves are validated where it
is built -- and so is an empty value.
Returns the lines only the caller owns the `---` fences.
"""
named = [key for key in self.order if key in values]
tail = sorted(key for key in values if key not in self.order)
return "\n".join(f"{key}: {self._render(key, values[key])}" for key in [*named, *tail])
return "\n".join(
f"{key}: {_emitted(self._render(key, values[key]))}" for key in [*named, *tail]
)
def _render(self, key: str, value: str) -> str:
# §5 mandates whitespace-run collapse for `source_query` only
@ -274,6 +434,12 @@ class FrontmatterSchema:
return " ".join(value.split()) if key in self.collapsed_keys else value
def _emitted(value: str) -> str:
if not value or yaml_flow_collection(value):
return value
return block_scalar(value)
# The v0.1 ingest stamp. A literal rather than a configurable value: it is what
# every bundle this library has already written carries, and recognising it is
# what keeps those bundles re-runnable under a later profile.
@ -380,7 +546,7 @@ def _split_frontmatter(text: str) -> tuple[dict[str, str], list[str]]:
continue
key, sep, value = line.partition(":")
if sep:
head[key.strip()] = value.strip()
head[key.strip()] = unquote_scalar(value.strip())
return head, []

View file

@ -57,7 +57,7 @@ from collections import Counter
from pathlib import Path
from . import consume as okf_consume
from .profiles import BundleProfile
from .profiles import BundleProfile, block_scalar
#: The template, resolved to a copy that exists wherever this module does.
#:
@ -389,7 +389,11 @@ def render(
bookkeeping=bookkeeping,
breaking=breaking,
)
header = f"---\nname: {name}\ndescription: {_description(bundle_id, total, ref)}\n---\n"
# Claude Code reads this header with a YAML reader, and `description`
# carries the root index's `bundle_id` raw -- a bundle this library did not
# build may call itself anything (K3-22).
description = block_scalar(_description(bundle_id, total, ref))
header = f"---\nname: {block_scalar(name)}\ndescription: {description}\n---\n"
return header + text, payload

View file

@ -35,6 +35,7 @@ from dataclasses import dataclass, field
from pathlib import Path
from .extract import strip_converter_attribute
from .profiles import unquote_scalar
# A document number is either an alpha-prefixed identifier (`N500`, `V720`,
# `R610.4`) or a dotted numeric section (`4.2.1`). A BARE integer is
@ -100,8 +101,12 @@ DERIVABLE_FIELDS = frozenset({"title", "number", "parent", "references"})
def _unquote(value: str) -> str:
# A producer quotes a scalar to keep YAML from retyping it (`version:
# '2021'` is a string, not an integer). The quotes are the encoding, not
# the value, and carrying them through would put them in the index.
if len(value) >= 2 and value[0] == value[-1] and value[0] in "\"'":
# the value, and carrying them through would put them in the index. A
# `"`-wrapped value is decoded the way the emitter wrote it (K3-22); a
# `'`-wrapped one keeps this module's older rule, unchanged.
if len(value) >= 2 and value[0] == value[-1] == '"':
return unquote_scalar(value)
if len(value) >= 2 and value[0] == value[-1] == "'":
return value[1:-1]
return value