html-conform 0.2.1

HTML5 conformance checking as a Rust dependency (vnu-comparable, no JVM runtime).
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204

//! HTML5 conformance checking with browser-style error recovery.
//!
//! `check`/`check_with_options` combine six finding sources, in order:
//! HTML parser diagnostics, RELAX NG schema (content-model) validation,
//! Schematron-style assertion (co-constraint) checking,
//! `<script type="importmap"|"speculationrules">` JSON content validation
//! (`src/scripts.rs` — a value/content-format check like the RELAX NG
//! datatypes, just on element text content instead of an attribute), and
//! `<meta http-equiv="Content-Security-Policy">` enforcement against
//! inline script/style content elsewhere in the document
//! (`src/csp_enforcement.rs` — a genuine cross-element check needing a
//! real CSP source-list parser, not expressible as a `rules/*.sch` rule
//! or a `w:*` datatype), and table cell-grid integrity
//! (`src/table_integrity.rs` — laying a table out over its
//! `colspan`/`rowspan` values needs mutable state carried forward across
//! cells, which XPath 1.0 has no way to express).

mod assertions;
mod csp_enforcement;
mod datatypes;
mod finding;
mod infoset;
mod parse;
mod schema;
mod scripts;
mod table_integrity;

use assertions::SchematronEngine;

pub use finding::{CheckError, CheckReport, Finding, Severity, SourceLocation};

/// Options that control which diagnostics are included in a check report.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub struct CheckOptions {
    /// Include recoverable HTML parser diagnostics in the report.
    pub include_parse_errors: bool,
}

impl Default for CheckOptions {
    fn default() -> Self {
        Self {
            include_parse_errors: true,
        }
    }
}

/// Checks a complete HTML document with the default options.
///
/// Findings are returned in parser order. Technical initialization failures are
/// returned as [`CheckError`] rather than being represented as findings.
pub fn check(html: &str) -> Result<CheckReport, CheckError> {
    check_with_options(html, CheckOptions::default())
}

/// Checks a complete HTML document with explicit options.
///
/// This function always uses HTML5 error recovery. `include_parse_errors`
/// controls whether recovered parser diagnostics become report findings.
/// Schema and assertion findings are always included — the checker only
/// omits parser diagnostics on request, not the conformance findings that
/// are the point of running it at all.
///
/// # Errors
///
/// Only for a genuine setup failure in this checker itself (the embedded
/// HTML5 schema failed to compile, or the embedded assertion rule set
/// failed to parse) — never for a document that is merely non-conformant,
/// which is reported through [`CheckReport::findings`] instead.
pub fn check_with_options(html: &str, options: CheckOptions) -> Result<CheckReport, CheckError> {
    let parsed = parse::parse(html);
    let document = infoset::normalize(parsed.document(), parsed.source());

    let mut findings = if options.include_parse_errors {
        parse::findings(&parsed)
    } else {
        Vec::new()
    };

    let schema_errors =
        schema::validate_document(&document).map_err(|message| CheckError::Initialization {
            message: format!("schema validation setup failed: {message}"),
        })?;
    findings.extend(schema::findings(&schema_errors));

    let assertion_failures = assertions::RuleSetEngine
        .check(&document)
        .map_err(|error| CheckError::Initialization {
            message: format!("assertion engine setup failed: {error}"),
        })?;
    findings.extend(assertions::findings(&assertion_failures));

    findings.extend(scripts::findings(parsed.document()));
    findings.extend(csp_enforcement::findings(parsed.document()));
    findings.extend(table_integrity::findings(parsed.document()));

    Ok(CheckReport { findings })
}

#[cfg(test)]
mod tests {
    use super::{CheckOptions, SourceLocation, check, check_with_options};

    #[test]
    fn valid_html_has_no_parser_findings() {
        let report = check(r#"<!doctype html><html lang="en"><title>Example</title><p>Hello</p>"#)
            .expect("HTML5 parsing should recover");

        assert!(report.findings.is_empty());
        assert!(!report.has_errors());
    }

    #[test]
    fn parser_diagnostics_can_be_excluded() {
        // Otherwise fully schema-conformant (has a <title>, per
        // schema/html5/meta.rnc's required head.inner) so that excluding
        // the recoverable parser diagnostic (an unknown entity reference)
        // leaves no findings at all — isolates this test to what it's
        // actually about (the `include_parse_errors` toggle), rather than
        // also depending on schema/assertion behavior.
        let report = check_with_options(
            r#"<!doctype html><html lang="en"><title>Example</title><p>&notAnEntity;</p>"#,
            CheckOptions {
                include_parse_errors: false,
            },
        )
        .expect("HTML5 parsing should recover");

        assert!(report.findings.is_empty());
    }

    #[test]
    fn parser_diagnostics_are_included_by_default() {
        let report =
            check(r#"<!doctype html><html lang="en"><title>Example</title><p>&notAnEntity;</p>"#)
                .expect("HTML5 parsing should recover");

        assert_eq!(report.findings.len(), 1);
        assert_eq!(report.findings[0].rule_id, "parser.html5");
    }

    #[test]
    fn schema_violation_is_reported_as_a_finding() {
        // No <title> — schema/html5/meta.rnc's head.inner requires one.
        // Fires against the *synthesized* implicit `<head>` (no explicit
        // `<head>` tag in this input), so `location` is `None` here — see
        // `schema_violation_location_is_populated_for_an_explicit_element`
        // below for the populated case.
        let report = check_with_options(
            r#"<!doctype html><html lang="en"><p>Hello</p>"#,
            CheckOptions {
                include_parse_errors: false,
            },
        )
        .expect("HTML5 parsing should recover");

        assert_eq!(report.findings.len(), 1);
        assert_eq!(report.findings[0].rule_id, "schema.html5");
        assert_eq!(report.findings[0].location, None);
        assert!(report.has_errors());
    }

    #[test]
    fn schema_violation_location_is_populated_for_an_explicit_element() {
        // Phase 08: `relax_ng::Element::Location` became generic
        // (`src/infoset.rs` sets it to `crate::finding::SourceLocation`
        // directly) — a schema.html5 finding against an *explicit*
        // element now carries a real, structured position, not `None`.
        let report = check_with_options(
            r#"<!doctype html><html lang="en"><title>x</title><p bogus="1">hi</p>"#,
            CheckOptions {
                include_parse_errors: false,
            },
        )
        .expect("HTML5 parsing should recover");

        assert_eq!(report.findings.len(), 1);
        assert_eq!(report.findings[0].rule_id, "schema.html5");
        assert_eq!(
            report.findings[0].location,
            Some(SourceLocation {
                line: 1,
                column: 48,
                byte_offset: 47,
            })
        );
    }

    #[test]
    fn assertion_violation_is_reported_as_a_finding() {
        let report = check_with_options(
            r#"<!doctype html><html lang="en"><title>Example</title><div aria-hidden="true" tabindex="0">x</div>"#,
            CheckOptions {
                include_parse_errors: false,
            },
        )
        .expect("HTML5 parsing should recover");

        assert_eq!(report.findings.len(), 1);
        assert_eq!(
            report.findings[0].rule_id,
            "assertion.aria.hidden-not-focusable"
        );
    }
}