Add config option to not cut tracing at recursion points

serde-reflection/src/de.rs

@@ -196,7 +196,7 @@ impl<'de, 'a> de::Deserializer<'de> for Deserializer<'de, 'a> {
         let mut format = Format::unknown();
         self.format
             .unify(Format::Option(Box::new(format.clone())))?;
-        if format.is_unknown() {
+        if format.is_unknown() || !self.tracer.config.cut_option_exploration {
             let inner = Deserializer::new(self.tracer, self.samples, &mut format);
             visitor.visit_some(inner)
         } else {
@@ -262,7 +262,7 @@ impl<'de, 'a> de::Deserializer<'de> for Deserializer<'de, 'a> {
     {
         let mut format = Format::unknown();
         self.format.unify(Format::Seq(Box::new(format.clone())))?;
-        if format.is_unknown() {
+        if format.is_unknown() || !self.tracer.config.cut_seq_exploration {
             // Simulate vector of size 1.
             let inner =
                 SeqDeserializer::new(self.tracer, self.samples, std::iter::once(&mut format));
@@ -329,7 +329,10 @@ impl<'de, 'a> de::Deserializer<'de> for Deserializer<'de, 'a> {
             key: Box::new(key_format.clone()),
             value: Box::new(value_format.clone()),
         })?;
-        if key_format.is_unknown() || value_format.is_unknown() {
+        if key_format.is_unknown()
+            || value_format.is_unknown()
+            || !self.tracer.config.cut_map_exploration
+        {
             // Simulate a map with one entry.
             let inner = SeqDeserializer::new(
                 self.tracer,
@@ -413,7 +416,8 @@ impl<'de, 'a> de::Deserializer<'de> for Deserializer<'de, 'a> {
         // If we have found all the variants OR if the enum is marked as
         // incomplete already, pick the first index.
         let index = if known_variants.len() == variants.len()
-            || self.tracer.incomplete_enums.contains(name)
+            || (self.tracer.incomplete_enums.contains(name)
+                && self.tracer.config.cut_enum_exploration)
         {
             0
         } else {
@@ -436,6 +440,8 @@ impl<'de, 'a> de::Deserializer<'de> for Deserializer<'de, 'a> {
         // Mark the enum as incomplete if this was not the last variant to explore.
         if known_variants.len() != variants.len() {
             self.tracer.incomplete_enums.insert(name.into());
+        } else {
+            self.tracer.incomplete_enums.remove(name);
         }
         // Compute the format for this variant.
         let inner = EnumDeserializer::new(self.tracer, self.samples, index, &mut value);

serde-reflection/src/trace.rs

@@ -75,6 +75,10 @@ pub struct TracerConfig {
     pub(crate) default_string_value: String,
     pub(crate) default_borrowed_bytes_value: &'static [u8],
     pub(crate) default_byte_buf_value: Vec<u8>,
+    pub(crate) cut_option_exploration: bool,
+    pub(crate) cut_seq_exploration: bool,
+    pub(crate) cut_map_exploration: bool,
+    pub(crate) cut_enum_exploration: bool,
 }
 
 impl Default for TracerConfig {
@@ -103,6 +107,10 @@ impl Default for TracerConfig {
             default_string_value: String::new(),
             default_borrowed_bytes_value: b"",
             default_byte_buf_value: Vec::new(),
+            cut_option_exploration: true,
+            cut_seq_exploration: true,
+            cut_map_exploration: true,
+            cut_enum_exploration: true,
         }
     }
 }
@@ -161,6 +169,38 @@ impl TracerConfig {
     define_default_value_setter!(default_string_value, String);
     define_default_value_setter!(default_borrowed_bytes_value, &'static [u8]);
     define_default_value_setter!(default_byte_buf_value, Vec<u8>);
+
+    /// Whether an optional value is *not* explored again after encountering it once.
+    ///
+    /// Warning: Disabling this option may lead to the tracing not terminating.
+    pub fn cut_option_exploration(mut self, value: bool) -> Self {
+        self.cut_option_exploration = value;
+        self
+    }
+
+    /// Whether a sequence is left empty after encountering it once.
+    ///
+    /// Warning: Disabling this option may lead to the tracing not terminating.
+    pub fn cut_seq_exploration(mut self, value: bool) -> Self {
+        self.cut_seq_exploration = value;
+        self
+    }
+
+    /// Whether a map is left empty after encountering it once.
+    ///
+    /// Warning: Disabling this option may lead to the tracing not terminating.
+    pub fn cut_map_exploration(mut self, value: bool) -> Self {
+        self.cut_map_exploration = value;
+        self
+    }
+
+    /// Whether an enum falls back to the first variant after encountering it once.
+    ///
+    /// Warning: Disabling this option may lead to the tracing not terminating.
+    pub fn cut_enum_exploration(mut self, value: bool) -> Self {
+        self.cut_enum_exploration = value;
+        self
+    }
 }
 
 impl Tracer {
@@ -245,6 +285,26 @@ impl Tracer {
         }
     }
 
+    /// Same as `trace_type_once` but if any uncovered variants remain in the
+    /// recursive format, we repeat the process.
+    /// We accumulate and return all the sampled values at the end.
+    pub fn trace_type_all_variants<'de, T>(
+        &mut self,
+        samples: &'de Samples,
+    ) -> Result<(Format, Vec<T>)>
+    where
+        T: Deserialize<'de>,
+    {
+        let mut values = Vec::new();
+        loop {
+            let (format, value) = self.trace_type_once::<T>(samples)?;
+            values.push(value);
+            if self.incomplete_enums.is_empty() {
+                return Ok((format, values));
+            }
+        }
+    }
+
     /// Trace a type `T` that is simple enough that no samples of values are needed.
     /// * If `T` is an enum, the tracing iterates until all variants of `T` are covered.
     /// * Accumulate and return all the sampled values at the end.