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Parser accepts inputs the grammar rejects (empty sections, unknown keywords, rule/call heads, lexical edge cases) #651
Description
Summary
The grammar verifier (#643) finds inputs the parser accepts and tests/grammar/grammar.pest rejects. Each is a KNOWN_DRIFT entry in src/query/datalog/parser/verifier.rs; a fix removes its entry. All are on main and v3.
| Entry | Example | Parser today |
|---|---|---|
UnterminatedString |
"abc (end of input) |
reads a string to the end |
BareColon |
: |
the keyword : |
LoneMinus |
- as a value |
the symbol - (pest's op_sym has no -) |
EmptyQuery |
(query []) |
accepted |
EmptyFind |
(query [:find :where [?e :a ?v]]) |
runs, one empty row |
EmptyWhere |
(query [:where]) |
accepted |
EmptyWith |
[:find (count ?e) :with :where …] |
accepted |
UnknownKeyword |
[:find ?e :foo :where …] |
:foo ignored when no value follows |
ResumedSection |
[:find ?x :any-valid-time ?y :where …] |
?y joins :find; the same after :as-of N, :valid-at "…", :max-* N |
CallHead |
(?r ?e) or (< ?e ?v) as a clause |
read as a rule call |
AggregateHead |
[:find (?x ?y) :where …] |
an aggregate named ?x |
RuleHead |
(rule [(foo ?x 1) …]), (rule [(?x ?y) …]) |
accepted; the grammar says a symbol then variable* |
Not reached by the default bound (it needs 5 tokens): a function call named by a variable, [(?f ?x) ?y], parsed as a UDF named ?f.
Fix
Tighten the parser for v3.0.0 (a breaking change for inputs that are accepted today; each gets a PRS code), except where the grammar should change instead (LoneMinus may be better fixed by documenting - as a symbol). These change which input is accepted, so they stay on v3. Each fix can add a corpus file to tests/grammar/invalid/syntax/.
Activity
Merge pull request #659 from project-minigraf/fix/651-parser-tightening
adityamukho commentedon Oct 20, 2026
Fixed on v3 by #659 (parser tightening, PRS-109..114; KNOWN_DRIFT now empty). Docs: project-minigraf/minigraf-docs#48. Ships in v3.0.0.