update bnf to 0.6 (copy #8864)

Cargo.lock

@@ -233,7 +233,7 @@ dependencies = [
  "mime",
  "multi_try",
  "multimap 0.10.1",
- "nom",
+ "nom 7.1.3",
  "nom_locate",
  "parking_lot",
  "percent-encoding",
@@ -1387,13 +1387,14 @@ dependencies = [
 
 [[package]]
 name = "bnf"
-version = "0.5.0"
+version = "0.6.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "14c09ea5795b3dd735ff47c4b8adf64c46e3ce056fa3c4880b865a352e4c40a2"
+checksum = "35b77b055f8cb1d566fa4ef55bc699f60eefb17927dc25fa454a05b6fabf7aa4"
 dependencies = [
- "getrandom 0.2.16",
- "nom",
- "rand 0.8.5",
+ "getrandom 0.3.4",
+ "hashbrown 0.16.1",
+ "nom 8.0.0",
+ "rand 0.9.2",
  "serde",
  "serde_json",
 ]
@@ -4416,6 +4417,15 @@ dependencies = [
  "minimal-lexical",
 ]
 
+[[package]]
+name = "nom"
+version = "8.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "df9761775871bdef83bee530e60050f7e54b1105350d6884eb0fb4f46c2f9405"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "nom_locate"
 version = "4.2.0"
@@ -4424,7 +4434,7 @@ checksum = "1e3c83c053b0713da60c5b8de47fe8e494fe3ece5267b2f23090a07a053ba8f3"
 dependencies = [
  "bytecount",
  "memchr",
- "nom",
+ "nom 7.1.3",
 ]
 
 [[package]]
@@ -5637,7 +5647,7 @@ dependencies = [
  "cookie-factory",
  "crc16",
  "log",
- "nom",
+ "nom 7.1.3",
 ]
 
 [[package]]
@@ -5941,7 +5951,6 @@ dependencies = [
  "http 1.4.0",
  "libfuzzer-sys",
  "log",
- "rand 0.8.5",
  "reqwest",
  "schemars",
  "serde",
@@ -6335,9 +6344,9 @@ dependencies = [
 
 [[package]]
 name = "serde_json"
-version = "1.0.148"
+version = "1.0.149"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3084b546a1dd6289475996f182a22aba973866ea8e8b02c51d9f46b1336a22da"
+checksum = "83fc039473c5595ace860d8c4fafa220ff474b3fc6bfdb4293327f1a37e94d86"
 dependencies = [
  "indexmap 2.12.1",
  "itoa",

fuzz/Cargo.toml

@@ -14,11 +14,9 @@ libfuzzer-sys = "=0.4.10"
 apollo-federation = { path = "../apollo-federation" }
 apollo-parser.workspace = true
 apollo-smith.workspace = true
-bnf = "0.5.0"
+bnf = "0.6"
 env_logger = "0.11.0"
 log = "0.4"
-# Required until https://github.com/shnewto/bnf/pull/175, remove when bnf 0.6 is out
-rand = "=0.8.5"
 reqwest = { workspace = true, features = ["json", "blocking"] }
 serde_json.workspace = true
 

fuzz/fuzz_targets/connector_selection_parse.rs

@@ -3,23 +3,26 @@
 use std::sync::LazyLock;
 
 use apollo_federation::connectors::JSONSelection;
+use bnf::CoverageGuided;
 use bnf::Grammar;
 use libfuzzer_sys::arbitrary;
 use libfuzzer_sys::arbitrary::Arbitrary;
 use libfuzzer_sys::fuzz_target;
 use libfuzzer_sys::Corpus;
-use rand::rngs::StdRng;
 
-fuzz_target!(|input: GeneratedSelection| -> Corpus {
-    // Generating a selection might choose a path which recurses too deeply, so
-    // we just mark those traversals as being rejected since they would require
-    // seeding and iterating the Rng.
-    let Some(selection) = input.0 else {
+/// Generations per fuzz input. CoverageGuided prefers grammar productions
+/// not yet exercised; multiple generations let that coverage accumulate.
+const GENERATIONS_PER_INPUT: usize = 8;
+
+fuzz_target!(|input: GeneratedSelections| -> Corpus {
+    if input.0.is_empty() {
         return Corpus::Reject;
-    };
+    }
 
-    let parsed = JSONSelection::parse(&selection).unwrap();
-    drop(parsed);
+    for selection in &input.0 {
+        let parsed = JSONSelection::parse(selection).unwrap();
+        drop(parsed);
+    }
 
     Corpus::Keep
 });
@@ -84,29 +87,30 @@ const BNF_GRAMMAR: &str = r##"
     "##;
 static GRAMMAR: LazyLock<Grammar> = LazyLock::new(|| BNF_GRAMMAR.parse().unwrap());
 
-struct GeneratedSelection(Option<String>);
-impl<'a> Arbitrary<'a> for GeneratedSelection {
+/// One fuzz input: a seed produces multiple grammar-generated strings via
+/// CoverageGuided, which prefers productions not yet used so we exercise
+/// more of the grammar per input.
+struct GeneratedSelections(Vec<String>);
+impl<'a> Arbitrary<'a> for GeneratedSelections {
     fn arbitrary(u: &mut libfuzzer_sys::arbitrary::Unstructured<'a>) -> arbitrary::Result<Self> {
         let bytes = <[u8; 32] as Arbitrary>::arbitrary(u)?;
-        let mut rng: StdRng = rand::SeedableRng::from_seed(bytes);
+        let mut strategy = CoverageGuided::from_seed(bytes);
 
-        let selection = GRAMMAR.generate_seeded(&mut rng).ok();
-        Ok(GeneratedSelection(selection))
+        let selections: Vec<String> = (0..GENERATIONS_PER_INPUT)
+            .filter_map(|_| GRAMMAR.generate_seeded_with_strategy(&mut strategy).ok())
+            .collect();
+        Ok(GeneratedSelections(selections))
     }
 }
 
-impl std::fmt::Debug for GeneratedSelection {
+impl std::fmt::Debug for GeneratedSelections {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        self.0
-            .as_deref()
-            .map(|selection| {
-                write!(f, "```original\n{}\n```", selection)?;
-                if let Ok(parsed) = JSONSelection::parse(selection) {
-                    write!(f, "\n\n```pretty\n{}\n```", parsed)?;
-                }
-
-                Ok(())
-            })
-            .unwrap_or(Ok(()))
+        for selection in &self.0 {
+            write!(f, "```original\n{}\n```", selection)?;
+            if let Ok(parsed) = JSONSelection::parse(selection) {
+                write!(f, "\n\n```pretty\n{}\n```", parsed)?;
+            }
+        }
+        Ok(())
     }
 }