Join every changed case to Snowflake's receipts in the coverage diff, whatever it expects

The snapshot took Snowflake's verdict from a case's checked phase, which is
none for every observe case, so a receipted observe case the parser stopped
accepting never reached the diff (#55's three regressions, audit 38bed22).

Each case result now carries what Snowflake's parser did, by every syntax
receipt of its SQL, setup and session whatever the case id: parsed when all
stopped after parsing with an errno other than 1003, refused when all are a
positioned 1003 or a 921, and nothing for a positionless 1003 or receipts that
disagree. The diff fails on a parsed case the parser now rejects, as before,
and also on a refused case it now accepts.

Author: kvlonge

crates/sqlquack-syntax-coverage/src/check/_helpers/join.rs

@@ -51,20 +51,44 @@ fn receipts_by_case(coverage: &SyntaxCoverage) -> BTreeMap<&str, Vec<&Receipt>>
     receipts
 }
 
+/// The receipts of each statement, by its SQL, setup and session hashes, whatever the case id.
+fn receipts_by_statement(coverage: &SyntaxCoverage) -> BTreeMap<(&str, &str, &str), Vec<&Receipt>> {
+    let mut receipts: BTreeMap<(&str, &str, &str), Vec<&Receipt>> = BTreeMap::new();
+    for receipt in &coverage.receipts {
+        receipts
+            .entry((
+                receipt.sql_sha256.as_str(),
+                receipt.setup_sha256.as_str(),
+                receipt.session_sha256.as_str(),
+            ))
+            .or_default()
+            .push(receipt);
+    }
+    receipts
+}
+
 /// Every join the checker needs, with each case judged against `parse`.
 pub(crate) fn join<'a>(
     coverage: &'a SyntaxCoverage,
     parse: &dyn Fn(&str) -> LocalVerdict,
 ) -> Joined<'a> {
     let receipts: BTreeMap<&str, Vec<&Receipt>> = receipts_by_case(coverage);
+    let statements: BTreeMap<(&str, &str, &str), Vec<&Receipt>> = receipts_by_statement(coverage);
     let mut cases: BTreeMap<&str, CaseResult> = BTreeMap::new();
     for case in coverage.cases.values().flatten() {
         let found: &[&Receipt] = receipts
             .get(case.case_id.as_str())
             .map_or(&[], Vec::as_slice);
+        let statement: &[&Receipt] = statements
+            .get(&(
+                case.sql_sha256.as_str(),
+                case.setup_sha256.as_str(),
+                case.session_sha256.as_str(),
+            ))
+            .map_or(&[], Vec::as_slice);
         cases.insert(
             case.case_id.as_str(),
-            case_result(case, found, parse(&case.sql)),
+            case_result(case, found, statement, parse(&case.sql)),
         );
     }
     Joined {

crates/sqlquack-syntax-coverage/src/check/_helpers/receipts.rs

@@ -2,7 +2,8 @@
 
 use std::collections::{BTreeMap, BTreeSet};
 
-use crate::check::models::{CaseResult, LocalVerdict, Reason};
+use crate::check::models::{CaseResult, LocalVerdict, Reason, SnowflakeSyntax};
+use crate::formats::constants::{SYNTAX_ERRNO, SYNTAX_ERRNO_42601};
 use crate::formats::models::{AccountSetting, Case, Expect, Phase, Receipt};
 
 /// A syntax receipt bound to exactly this case's SQL, setup, session and capture, with a query id.
@@ -61,8 +62,35 @@ fn agreement(phase: Phase, local: &LocalVerdict, terminates: bool) -> Result<boo
     }
 }
 
-/// The case's result against its receipts and the current parser's verdict.
-pub(crate) fn case_result(case: &Case, receipts: &[&Receipt], local: LocalVerdict) -> CaseResult {
+/// What Snowflake's parser did by the syntax receipts of the case's statement; none unless all agree.
+fn snowflake_syntax(statement_receipts: &[&Receipt]) -> Option<SnowflakeSyntax> {
+    let verdicts: BTreeSet<Option<SnowflakeSyntax>> = statement_receipts
+        .iter()
+        .filter(|receipt| receipt.measure.is_none())
+        .map(|receipt| match (receipt.phase, receipt.errno) {
+            (Phase::SyntaxError, Some(errno))
+                if errno == SYNTAX_ERRNO || errno == SYNTAX_ERRNO_42601 =>
+            {
+                Some(SnowflakeSyntax::Refused)
+            }
+            (Phase::SyntaxError, _) => None,
+            (_, Some(errno)) if errno == SYNTAX_ERRNO => None,
+            _ => Some(SnowflakeSyntax::Parsed),
+        })
+        .collect();
+    match verdicts.len() {
+        1 => verdicts.into_iter().next().flatten(),
+        _ => None,
+    }
+}
+
+/// The case's result against its receipts, its statement's receipts and the parser's verdict.
+pub(crate) fn case_result(
+    case: &Case,
+    receipts: &[&Receipt],
+    statement_receipts: &[&Receipt],
+    local: LocalVerdict,
+) -> CaseResult {
     let (phase, reason, semantic_only): (Option<Phase>, Option<Reason>, bool) =
         match receipt_phase(case, receipts) {
             _ if case.expect == Some(Expect::Observe) => {
@@ -84,6 +112,7 @@ pub(crate) fn case_result(case: &Case, receipts: &[&Receipt], local: LocalVerdic
         local,
         reason,
         semantic_only,
+        snowflake: snowflake_syntax(statement_receipts),
         account_state: receipts
             .iter()
             .filter(|receipt| admissible(case, receipt))

crates/sqlquack-syntax-coverage/src/check/models.rs

@@ -76,6 +76,16 @@ pub enum Reason {
     BlockedByHold,
 }
 
+/// What Snowflake's parser did with a case's statement, by every receipt of its SQL, setup and session.
+#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Serialize)]
+#[serde(rename_all = "snake_case")]
+pub enum SnowflakeSyntax {
+    /// Every receipt stopped after parsing or succeeded, with an errno other than 1003.
+    Parsed,
+    /// Every receipt is a syntax error: errno 1003 with a parse position, or errno 921.
+    Refused,
+}
+
 /// One case's result: its receipts against the current parser.
 #[derive(Clone, Debug, PartialEq, Eq, Serialize)]
 pub struct CaseResult {
@@ -89,6 +99,8 @@ pub struct CaseResult {
     pub reason: Option<Reason>,
     /// Agrees, while Snowflake stopped after parsing (semantic, runtime or unsupported phase).
     pub semantic_only: bool,
+    /// What Snowflake's parser did, whatever the case expects; none on disagreeing or no receipts.
+    pub snowflake: Option<SnowflakeSyntax>,
     /// The account parameters its admissible receipts ran under (decision D120).
     #[serde(skip_serializing_if = "BTreeMap::is_empty")]
     pub account_state: BTreeMap<String, AccountSetting>,

crates/sqlquack-syntax-coverage/src/check/tests/helpers.rs

@@ -66,6 +66,11 @@ pub(crate) fn reshaped(sql: &str) -> LocalVerdict {
     vec![structural(sql), accepted_as("another tree")].swap_remove(usize::from(sql == "SELECT 17"))
 }
 
+/// `structural`, except that `SELECT 17` is rejected.
+pub(crate) fn rejecting_select_17(sql: &str) -> LocalVerdict {
+    vec![structural(sql), LocalVerdict::Rejected].swap_remove(usize::from(sql == "SELECT 17"))
+}
+
 /// `structural`, except that `SELECT FROM` crashes instead of being rejected.
 pub(crate) fn crashing_on_select_from(sql: &str) -> LocalVerdict {
     vec![structural(sql), crashing(sql)].swap_remove(usize::from(sql == "SELECT FROM"))

crates/sqlquack-syntax-coverage/src/cli/_helpers/commands.rs

@@ -339,13 +339,17 @@ fn read_snapshot(path: &Path) -> Result<Snapshot, ExitCode> {
 
 /// Lines naming each non-empty list of the diff.
 fn diff_lines(diff: &SnapshotDiff) -> Vec<String> {
-    let lists: [(&str, &Vec<String>); 8] = [
+    let lists: [(&str, &Vec<String>); 9] = [
         ("REGRESSION forms lost", &diff.forms_lost),
         ("REGRESSION obligations lost", &diff.obligations_lost),
         (
             "REGRESSION Snowflake-parsed cases the parser now rejects",
             &diff.parsed_cases_refused,
         ),
+        (
+            "REGRESSION Snowflake syntax errors the parser now accepts",
+            &diff.syntax_error_cases_accepted,
+        ),
         ("CATALOGUE files changed", &diff.catalogue_files_changed),
         ("CATALOGUE forms added", &diff.forms_added),
         ("CATALOGUE forms removed", &diff.forms_removed),
@@ -382,6 +386,7 @@ pub(crate) fn diff(
         &diff.forms_lost,
         &diff.obligations_lost,
         &diff.parsed_cases_refused,
+        &diff.syntax_error_cases_accepted,
         &diff.catalogue_files_changed,
         &diff.forms_added,
         &diff.forms_removed,

crates/sqlquack-syntax-coverage/src/formats/constants.rs

@@ -88,3 +88,9 @@ pub const DCM_LINE: &str = "line ";
 
 /// What separates an inner error's line from its position.
 pub const DCM_POSITION: &str = " at position ";
+
+/// Snowflake's errno for a syntax error; with a parse position it is a refusal by the parser.
+pub const SYNTAX_ERRNO: i64 = 1003;
+
+/// Snowflake's errno 921, SQLSTATE 42601, reviewed as a syntax refusal.
+pub const SYNTAX_ERRNO_42601: i64 = 921;

crates/sqlquack-syntax-coverage/src/report/main/diff_snapshots.rs

@@ -59,5 +59,10 @@ pub fn diff_snapshots(base: &Snapshot, head: &Snapshot) -> SnapshotDiff {
             .intersection(&head.refused_cases)
             .cloned()
             .collect(),
+        syntax_error_cases_accepted: base
+            .syntax_error_cases_rejected
+            .intersection(&head.syntax_error_cases_accepted)
+            .cloned()
+            .collect(),
     }
 }

crates/sqlquack-syntax-coverage/src/report/main/snapshot.rs

@@ -2,25 +2,28 @@
 
 use std::collections::{BTreeMap, BTreeSet};
 
-use crate::check::models::{CheckResult, LocalVerdict};
+use crate::check::models::{CheckResult, LocalVerdict, SnowflakeSyntax};
 use crate::formats::constants::{ALIASES_FILE, CATALOGUE_DIR, SNAPSHOT_FORMAT, SOURCES_FILE};
-use crate::formats::models::Phase;
 use crate::report::models::Snapshot;
 
 /// Whether a coverage path belongs to the catalogue rather than to obligations or evidence.
 fn is_catalogue_file(path: &str) -> bool {
     path == SOURCES_FILE || path == ALIASES_FILE || path.starts_with(&format!("{CATALOGUE_DIR}/"))
 }
 
-/// The receipted cases Snowflake parsed whose local verdict `accepted` says whether it parsed too.
-fn snowflake_parsed(check: &CheckResult, accepted: bool) -> BTreeSet<String> {
+/// Cases whose receipts say `snowflake` and whose parser verdict is acceptance when `accepted`.
+fn by_snowflake(
+    check: &CheckResult,
+    snowflake: SnowflakeSyntax,
+    accepted: bool,
+) -> BTreeSet<String> {
     check
         .forms
         .iter()
         .flat_map(|form| &form.obligations)
         .flat_map(|obligation| &obligation.cases)
         .filter(|case| {
-            case.phase.is_some_and(|phase| phase != Phase::SyntaxError)
+            case.snowflake == Some(snowflake)
                 && matches!(case.local, LocalVerdict::Accepted { .. }) == accepted
                 && !matches!(case.local, LocalVerdict::Failed { .. })
         })
@@ -55,7 +58,9 @@ pub fn snapshot(
             .filter(|obligation| obligation.required && obligation.reason.is_none())
             .map(|obligation| obligation.id.clone())
             .collect(),
-        parsed_cases: snowflake_parsed(check, true),
-        refused_cases: snowflake_parsed(check, false),
+        parsed_cases: by_snowflake(check, SnowflakeSyntax::Parsed, true),
+        refused_cases: by_snowflake(check, SnowflakeSyntax::Parsed, false),
+        syntax_error_cases_rejected: by_snowflake(check, SnowflakeSyntax::Refused, false),
+        syntax_error_cases_accepted: by_snowflake(check, SnowflakeSyntax::Refused, true),
     }
 }

crates/sqlquack-syntax-coverage/src/report/models.rs

@@ -64,6 +64,12 @@ pub struct Snapshot {
     /// Receipted cases Snowflake parsed that the parser rejects.
     #[serde(default)]
     pub refused_cases: BTreeSet<String>,
+    /// Receipted cases Snowflake refused as syntax that the parser rejects too.
+    #[serde(default)]
+    pub syntax_error_cases_rejected: BTreeSet<String>,
+    /// Receipted cases Snowflake refused as syntax that the parser accepts, opaque or not.
+    #[serde(default)]
+    pub syntax_error_cases_accepted: BTreeSet<String>,
 }
 
 /// One snapshot against a later one; coverage and catalogue changes kept apart.
@@ -82,4 +88,6 @@ pub struct SnapshotDiff {
     pub obligations_gained: Vec<String>,
     /// Cases Snowflake parsed that the base parser accepted, opaque or not, and the head rejects.
     pub parsed_cases_refused: Vec<String>,
+    /// Cases Snowflake refused as syntax that the base parser rejected and the head accepts.
+    pub syntax_error_cases_accepted: Vec<String>,
 }

crates/sqlquack-syntax-coverage/src/report/tests.rs

@@ -2,5 +2,7 @@
 mod helpers;
 #[path = "tests/test_diff_snapshots.rs"]
 mod test_diff_snapshots;
+#[path = "tests/test_parser_changes.rs"]
+mod test_parser_changes;
 #[path = "tests/test_types.rs"]
 mod test_types;