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ProbeLabs23 findings · 123 requirements

The fastest JSON parser for Go — formally verified with ReqProof (real library, master).

All requirements
RequirementSYS-REQ-016SystemApproved

When the JSON input is well formed, a key path is provided, and the addressed path does not exist, the parser shall return the defined not-found result with `NotExist`, offset `-1`, and `KeyPathNotFoundError`.

This requirement changed after its last recorded review, so approval is stale. Automated checks pass and 4/4 obligations are satisfied.
PriorityshallTypeguaranteeCategoryfunctionalComponentparserAssuranceBFindingsnone open

Specification

The requirement exactly as authored — its complete prose text and, where present, the formal FRETish sentence it compiles to.

Description

When the JSON input is well formed, a key path is provided, and the addressed path does not exist, the parser shall return the defined not-found result with `NotExist`, offset `-1`, and `KeyPathNotFoundError`.

FRETish formula
the parser shall always satisfy !json_input_is_well_formed | !key_path_is_provided | addressed_path_exists | returns_missing_path_result_for_well_formed_lookup
View full formal model

Rationale & tags

Why this requirement exists, and how it is categorised.

The Get contract is not complete unless the missing-path outcome is specified independently from successful lookup and incomplete-input failure.

decompositionget

Verification & provenance

How this requirement was checked: the review trail, edit history, and the machine-analysis status terms (each ⓘ explains what it means).

Assurance levelB
Formalizationvalid
Realizabilityrealizable
Vacuitychecked_ok
Strategyfretish

Review

Status
approved
Reviewer
Buger · lead_engineer
Reviewed
Jul 26, 2026, 18:45 UTC
Re-approved after SYS-REQ-111 obligation delegation

History

Created
Apr 14, 2026, 00:00 UTC · Created via CLI
Modified
Jul 26, 2026, 18:58 UTC · Created via CLI

Change history

Every recorded revision of this requirement's source file — newest first, each with its commit message and the diff for that change.

Every recorded revision of this object's source — newest first, each with the commit message and its file-level diff.

Obligations

What this requirement must witness to be considered satisfied — the required evidence, and the tests that discharge each one.

3 obligations · 3 discharged

Browse the catalogue
Discharged
If it were violatedLow

Get returns a stale value slice from a previously cached offset instead of KeyPathNotFoundError when the path is missing, leaking a sibling field's bytes to the caller (silent data corruption).

Discharging evidence1/1 required witnessed
  • nominalrequiredpresent
    Covered by 1 test
Discharged

Behavior specified when inputs are nil, null, or zero-value.

If it were violatedHigh

An empty-string key component flowing into searchKeys on nil-or-zero-length internal slices triggers an unguarded keys[i][0] / p[level][0] dereference, crashing the goroutine (OSS-Fuzz 4649128545288192 panic class, SYS-REQ-111 hazard).

Discharging evidence2/2 required witnessed
  • negativerequiredpresent
    Covered by 1 test
  • nominalrequiredpresent
    Covered by 1 test
Discharged
If it were violatedHigh

An empty-string key component is structurally a no-effective-path case; if the early guard regresses the keys[i][0] dereference panics with index-out-of-range on the empty component slice (SYS-REQ-111 hazard class).

Discharging evidence1/1 required witnessed
  • nominalrequiredpresent
    Covered by 1 test

Formula evidence

The formal formula behind this requirement, the variables it is written over, and the tests that exercise it (each term is explained inline).

FRETish formula

the parser shall always satisfy !json_input_is_well_formed | !key_path_is_provided | addressed_path_exists | returns_missing_path_result_for_well_formed_lookup

Variables

NameTypeDirectionDescription
json_input_is_well_formedTrue when the provided JSON byte slice is well formed for the lookup case under evaluation.
key_path_is_providedTrue when the caller supplies at least one key-path segment for the lookup case under evaluation.
addressed_path_existsTrue when the requested key path resolves to a value in the JSON input under evaluation.
returns_missing_path_result_for_well_formed_lookupTrue when Get reports the defined not-found outcome for a well-formed lookup whose addressed path does not exist.

Witnesses· 5 scenarios total

  • TestMCDC_SYS_REQ_016_Row1_TriggerFalse
    exercises 1 condition scenario
  • TestMCDC_SYS_REQ_016_Row2_NoKeyPath
    exercises 1 condition scenario
  • TestMCDC_SYS_REQ_016_Row3_InvariantViolation
    exercises 1 condition scenario
  • TestMCDC_SYS_REQ_016_Row4_MissingPathResult
    exercises 1 condition scenario
  • TestMCDC_SYS_REQ_016_Row5_AddressedPathExists
    exercises 1 condition scenario

MC/DC truth table· 5 rows

Each row assigns the formula's conditions (T/F) and shows the Result— the formula's value for that input row, not a test pass/fail. A row proves a condition when flipping only that condition flips the outcome. The test that covers each row is linked.

Covereda test exercises this rowExempteda reviewed mcdc:ignoreNo-actionfalse-result row satisfied by designUncoveredneeds a covering test
#addressed_path_existsjson_input_is_well_formedkey_path_is_providedreturns_missing_path_result_for_well_formed_lookupResultProvesCovering test
1FFTFTjson_input_is_well_formed
2FTFFTkey_path_is_provided
3FTTFFaddressed_path_exists
4FTTTTreturns_missing_path_result_for_well_formed_lookup
5TTTFTaddressed_path_exists

Its place

This requirement shown inside its trace neighbourhood — the parents it satisfies, the code and tests attached to it, and its findings.

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Trace evidence

The concrete artifacts linked to this requirement — implementing code, verifying tests, documents, and the findings raised against it.

Impact

Blast radius — if you change this requirement, what else may need re-checking, and what it in turn depends on.

If you change this

Requirements
0
Files
1
Tests
6
At-risk contracts
0

Files to re-check (1)

  • parser.goparser.go

Tests to re-run (6)

  • deep_spec_test.godeep_spec_test.go
  • empty_key_path_test.goempty_key_path_test.go
  • mcdc_spec_witnesses_test.gomcdc_spec_witnesses_test.go
  • obligation_evidence_test.goobligation_evidence_test.go
  • parser_test.goparser_test.go
  • sys_req_110_111_witness_test.gosys_req_110_111_witness_test.go

What this rests on

Discussions

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