Add std feature gate and no_std clip

Makefile

@@ -86,6 +86,18 @@ build:
 	cargo build --package aimdb-tokio-adapter --features "tokio-runtime,tracing,observability"
 	@printf "$(YELLOW)  → Building sync wrapper$(NC)\n"
 	cargo build --package aimdb-sync
+	@printf "$(YELLOW)  → Building sync wrapper (no_std)$(NC)\n"
+	cargo build --package aimdb-sync --no-default-features
+	@printf "$(YELLOW)  → Asserting no tokio in sync wrapper (no_std)$(NC)\n"
+	@out=$$(cargo tree -p aimdb-sync --no-default-features -e features,no-dev 2>&1) || { \
+		printf "$(RED)✗ cargo tree failed — refusing to pass vacuously:$(NC)\n"; \
+		printf '%s\n' "$$out"; exit 1; \
+	}; \
+	if printf '%s\n' "$$out" | grep -qi tokio; then \
+		printf "$(RED)✗ tokio leaked into the no_std build$(NC)\n"; \
+		printf '%s\n' "$$out" | grep -i tokio; exit 1; \
+	fi
+	@printf "$(BLUE)✓ no_std graph is tokio-free$(NC)\n"
 	@printf "$(YELLOW)  → Building codegen library$(NC)\n"
 	cargo build --package aimdb-codegen
 	@printf "$(YELLOW)  → Building CLI tools$(NC)\n"
@@ -157,6 +169,10 @@ test:
 	cargo test --package aimdb-wasm-adapter --no-default-features --features observability --lib
 	@printf "$(YELLOW)  → Testing sync wrapper$(NC)\n"
 	cargo test --package aimdb-sync
+	@printf "$(YELLOW)  → Testing sync wrapper (no_std)$(NC)\n"
+	cargo test --package aimdb-sync --no-default-features
+	@printf "$(YELLOW)  → Testing sync wrapper (data-contracts: set_value family)$(NC)\n"
+	cargo test --package aimdb-sync --features data-contracts
 	@printf "$(YELLOW)  → Testing codegen library$(NC)\n"
 	cargo test --package aimdb-codegen
 	@printf "$(YELLOW)  → Testing CLI tools$(NC)\n"
@@ -240,6 +256,10 @@ clippy:
 	cargo clippy --package aimdb-embassy-adapter --target thumbv7em-none-eabihf --features "embassy-runtime,embassy-net-support" -- -D warnings
 	@printf "$(YELLOW)  → Clippy on sync wrapper$(NC)\n"
 	cargo clippy --package aimdb-sync --all-targets -- -D warnings
+	@printf "$(YELLOW)  → Clippy on sync wrapper (no_std)$(NC)\n"
+	cargo clippy --package aimdb-sync --no-default-features --all-targets -- -D warnings
+	@printf "$(YELLOW)  → Clippy on sync wrapper (data-contracts)$(NC)\n"
+	cargo clippy --package aimdb-sync --features data-contracts --all-targets -- -D warnings
 	@printf "$(YELLOW)  → Clippy on client library$(NC)\n"
 	cargo clippy --package aimdb-client --all-targets -- -D warnings
 	@printf "$(YELLOW)  → Clippy on client library (serial transport arm)$(NC)\n"
@@ -392,6 +412,8 @@ test-embedded:
 	cargo check --package aimdb-tcp-connector --target thumbv7em-none-eabihf --target-dir $(EMBEDDED_CHECK_TARGET_DIR) --no-default-features --features "embassy-runtime"
 	@printf "$(YELLOW)  → Checking aimdb-tcp-connector (Embassy TCP client + defmt) on thumbv7em-none-eabihf target$(NC)\n"
 	cargo check --package aimdb-tcp-connector --target thumbv7em-none-eabihf --target-dir $(EMBEDDED_CHECK_TARGET_DIR) --no-default-features --features "embassy-runtime,defmt"
+	@printf "$(YELLOW)  → Checking aimdb-sync (no_std) on thumbv7em-none-eabihf target$(NC)\n"
+	cargo check --package aimdb-sync --target thumbv7em-none-eabihf --target-dir $(EMBEDDED_CHECK_TARGET_DIR) --no-default-features
 
 ## Example projects
 examples:

aimdb-sync/Cargo.toml

@@ -11,12 +11,18 @@ categories = ["database", "api-bindings"]
 
 [dependencies]
 # Core dependencies
-aimdb-core = { path = "../aimdb-core", version = "1.1.0" }
-aimdb-tokio-adapter = { path = "../aimdb-tokio-adapter", version = "0.6.0" }
+# `default-features = false` is load-bearing: aimdb-core's default set is
+# ["std", "alloc", "derive"], so inheriting it would pull anyhow/serde/remote
+# into the `--no-default-features` build and silently un-no_std this crate.
+# The `std` feature below forwards to `aimdb-core/std` for the std path.
+aimdb-core = { path = "../aimdb-core", version = "1.1.0", default-features = false, features = [
+    "alloc",
+] }
+aimdb-tokio-adapter = { path = "../aimdb-tokio-adapter", version = "0.6.0", optional = true }
 tracing = { workspace = true, optional = true }
 
 # Tokio for channels and runtime
-tokio = { version = "1.40", features = ["sync", "rt", "time", "macros"] }
+tokio = { version = "1.40", features = ["sync", "rt", "time", "macros"], optional = true }
 
 # Error handling
 thiserror = { version = "2.0.16", default-features = false }
@@ -38,7 +44,7 @@ serde_json = "1.0"
 [features]
 default = ["std"]
 
-std = []
+std = ["aimdb-core/std", "dep:tokio", "dep:aimdb-tokio-adapter"]
 
 # Enable tracing for debugging
 tracing = ["dep:tracing", "aimdb-core/tracing"]

aimdb-sync/src/consumer.rs

@@ -1,10 +1,11 @@
 //! Synchronous consumer for typed records.
 
 use crate::{SyncError, SyncResult};
-use std::fmt::Debug;
+use alloc::sync::Arc;
+use core::fmt::Debug;
+use core::time::Duration;
 use std::sync::mpsc;
-use std::sync::{Arc, Mutex};
-use std::time::Duration;
+use std::sync::Mutex;
 
 /// Synchronous consumer for records of type `T`.
 ///
@@ -49,7 +50,7 @@ where
     T: Send + Sync + 'static + Debug + Clone,
 {
     /// Channel receiver for consumer data
-    /// Wrapped in Arc<Mutex> so it can be shared but only one thread receives at a time
+    /// Wrapped in `Arc<Mutex>` so it can be shared but only one thread receives at a time
     rx: Arc<Mutex<mpsc::Receiver<T>>>,
 }
 
@@ -87,7 +88,6 @@ where
     ///
     /// # #[derive(Debug, Clone)]
     /// # struct MyData { value: i32 }
-    /// # #[cfg(feature = "std")]
     /// # fn main() -> SyncResult<()> {
     /// let handle = AimDbBuilder::new()
     ///     .runtime(Arc::new(TokioAdapter))
@@ -127,7 +127,6 @@ where
     ///
     /// # #[derive(Debug, Clone)]
     /// # struct MyData { value: i32 }
-    /// # #[cfg(feature = "std")]
     /// # fn main() -> SyncResult<()> {
     /// let handle = AimDbBuilder::new()
     ///     .runtime(Arc::new(TokioAdapter))
@@ -168,7 +167,6 @@ where
     ///
     /// # #[derive(Debug, Clone)]
     /// # struct MyData { value: i32 }
-    /// # #[cfg(feature = "std")]
     /// # fn main() -> SyncResult<()> {
     /// let handle = AimDbBuilder::new()
     ///     .runtime(Arc::new(TokioAdapter))
@@ -216,7 +214,6 @@ where
     ///
     /// # #[derive(Debug, Clone)]
     /// # struct MyData { value: i32 }
-    /// # #[cfg(feature = "std")]
     /// # fn main() -> SyncResult<()> {
     /// let handle = AimDbBuilder::new()
     ///     .runtime(Arc::new(TokioAdapter))
@@ -269,7 +266,6 @@ where
     ///
     /// # #[derive(Debug, Clone)]
     /// # struct MyData { value: i32 }
-    /// # #[cfg(feature = "std")]
     /// # fn main() -> SyncResult<()> {
     /// let handle = AimDbBuilder::new()
     ///     .runtime(Arc::new(TokioAdapter))

aimdb-sync/src/handle.rs

@@ -2,10 +2,10 @@
 
 use crate::{SyncError, SyncResult};
 use aimdb_core::{log_error, log_warn, AimDb, AimDbBuilder, DbError, DbResult};
-use std::fmt::Debug;
-use std::sync::Arc;
+use alloc::sync::Arc;
+use core::fmt::Debug;
+use core::time::Duration;
 use std::thread::{self, JoinHandle};
-use std::time::Duration;
 use tokio::sync::mpsc;
 
 /// Default channel capacity for sync producers and consumers.
@@ -50,7 +50,6 @@ pub trait AimDbBuilderSyncExt {
     /// use std::sync::Arc;
     ///
     /// # #[derive(Debug, Clone)] struct MyData { value: f32 }
-    /// # #[cfg(feature = "std")]
     /// # fn main() -> SyncResult<()> {
     /// let mut builder = AimDbBuilder::new()
     ///     .runtime(Arc::new(TokioAdapter::new()?));

aimdb-sync/src/lib.rs

@@ -43,7 +43,8 @@
 //!
 //! ## Quick Start
 //!
-//! ```no_run
+#![cfg_attr(feature = "std", doc = "```no_run")]
+#![cfg_attr(not(feature = "std"), doc = "```ignore")]
 //! use aimdb_core::{AimDbBuilder, buffer::BufferCfg};
 //! use aimdb_tokio_adapter::{TokioAdapter, TokioRecordRegistrarExt};
 //! use aimdb_sync::{AimDbBuilderSyncExt, SyncResult};
@@ -53,8 +54,6 @@
 //! struct Temperature {
 //!     celsius: f32,
 //! }
-//! // Guard againts the use of TokioAdapter in case of "std"
-//! # #[cfg(feature = "std")]
 //! # fn main() -> SyncResult<()> {
 //! // Build and attach database (NO #[tokio::main] NEEDED!)
 //! let adapter = Arc::new(TokioAdapter::new()?);
@@ -87,7 +86,8 @@
 //!
 //! Both `SyncProducer` and `SyncConsumer` can be cloned and shared across threads:
 //!
-//! ```no_run
+#![cfg_attr(feature = "std", doc = "```no_run")]
+#![cfg_attr(not(feature = "std"), doc = "```ignore")]
 //! use std::thread;
 //! # use aimdb_sync::{SyncConsumer, SyncProducer};
 //! # #[derive(Debug, Clone)] struct Temperature { celsius: f32 }
@@ -114,7 +114,8 @@
 //! Note: Cloning a `SyncConsumer` shares the same channel, so only one thread
 //! will receive each value. For independent subscriptions, create multiple consumers:
 //!
-//! ```no_run
+#![cfg_attr(feature = "std", doc = "```no_run")]
+#![cfg_attr(not(feature = "std"), doc = "```ignore")]
 //! # use aimdb_sync::{AimDbHandle, SyncResult};
 //! # #[derive(Debug, Clone)] struct Temperature { celsius: f32 }
 //! # fn demo(handle: &AimDbHandle) -> SyncResult<()> {
@@ -131,7 +132,8 @@
 //! By default, both producers and consumers use a channel capacity of 100.
 //! You can customize this per record type using the `_with_capacity` methods:
 //!
-//! ```no_run
+#![cfg_attr(feature = "std", doc = "```no_run")]
+#![cfg_attr(not(feature = "std"), doc = "```ignore")]
 //! # use aimdb_sync::{AimDbHandle, SyncResult};
 //! # #[derive(Debug, Clone)] struct SensorData { value: f32 }
 //! # #[derive(Debug, Clone)] struct RareEvent { code: u8 }
@@ -167,7 +169,8 @@
 //! ### Solutions for SingleLatest Semantics
 //!
 //! 1. **Use `get_latest()`** - Drains the channel to get the most recent value:
-//!    ```no_run
+#![cfg_attr(feature = "std", doc = "```no_run")]
+#![cfg_attr(not(feature = "std"), doc = "```ignore")]
 //!    # use aimdb_sync::SyncResult;
 //!    # #[derive(Debug, Clone)] struct Temperature { celsius: f32 }
 //!    # fn demo(consumer: &aimdb_sync::SyncConsumer<Temperature>) -> SyncResult<()> {
@@ -178,7 +181,8 @@
 //!    ```
 //!
 //! 2. **Use capacity=1** - Minimize queueing:
-//!    ```no_run
+#![cfg_attr(feature = "std", doc = "```no_run")]
+#![cfg_attr(not(feature = "std"), doc = "```ignore")]
 //!    # #[derive(Debug, Clone)] struct Temperature { celsius: f32 }
 //!    # fn demo(handle: &aimdb_sync::AimDbHandle) -> aimdb_sync::SyncResult<()> {
 //!    let consumer = handle.consumer_with_capacity::<Temperature>("sensor.temp", 1)?;
@@ -223,7 +227,8 @@
 //!   and return any errors that occur in the async context
 //! - `try_set()` sends immediately without waiting for the produce result (fire-and-forget)
 //!
-//! ```no_run
+#![cfg_attr(feature = "std", doc = "```no_run")]
+#![cfg_attr(not(feature = "std"), doc = "```ignore")]
 //! # use aimdb_sync::{DbError, SyncError, SyncProducer};
 //! # use aimdb_core::{log_error};
 //! # #[derive(Debug, Clone)] struct Temperature { celsius: f32 }
@@ -245,16 +250,23 @@
 #![warn(missing_docs)]
 #![warn(clippy::all)]
 #![cfg_attr(docsrs, feature(doc_cfg))]
+#![cfg_attr(not(feature = "std"), no_std)]
 
 extern crate alloc;
 
+#[cfg(feature = "std")]
 mod consumer;
 mod error;
+#[cfg(feature = "std")]
 mod handle;
+#[cfg(feature = "std")]
 mod producer;
 
+#[cfg(feature = "std")]
 pub use consumer::SyncConsumer;
+#[cfg(feature = "std")]
 pub use handle::{AimDbBuilderSyncExt, AimDbHandle, AimDbSyncExt, DEFAULT_SYNC_CHANNEL_CAPACITY};
+#[cfg(feature = "std")]
 pub use producer::SyncProducer;
 
 pub use error::{SyncError, SyncResult};

aimdb-sync/src/producer.rs

@@ -2,9 +2,9 @@
 
 use crate::{SyncError, SyncResult};
 use aimdb_core::DbResult;
-use std::fmt::Debug;
-use std::sync::Arc;
-use std::time::Duration;
+use alloc::sync::Arc;
+use core::fmt::Debug;
+use core::time::Duration;
 use tokio::sync::{mpsc, oneshot};
 
 /// Synchronous producer for records of type `T`.
@@ -124,7 +124,6 @@ where
     ///
     /// # #[derive(Debug, Clone)]
     /// # struct MyData { value: i32 }
-    /// # #[cfg(feature = "std")]
     /// # fn main() -> SyncResult<()> {
     /// let handle = AimDbBuilder::new()
     ///     .runtime(Arc::new(TokioAdapter))
@@ -161,7 +160,6 @@ where
     ///
     /// # #[derive(Debug, Clone)]
     /// # struct MyData { value: i32 }
-    /// # #[cfg(feature = "std")]
     /// # fn main() -> SyncResult<()> {
     /// let handle = AimDbBuilder::new()
     ///     .runtime(Arc::new(TokioAdapter))
@@ -199,7 +197,6 @@ where
     ///
     /// # #[derive(Debug, Clone)]
     /// # struct MyData { value: i32 }
-    /// # #[cfg(feature = "std")]
     /// # fn main() -> SyncResult<()> {
     /// let handle = AimDbBuilder::new()
     ///     .runtime(Arc::new(TokioAdapter))
@@ -243,8 +240,6 @@ where
     /// # Example
     ///
     /// ```no_run
-    /// # #[cfg(feature = "data-contracts")]
-    /// # #[cfg(feature = "std")]
     /// # use aimdb_sync::SyncResult;
     /// # fn main() -> SyncResult<()> {
     /// use aimdb_core::AimDbBuilder;
@@ -272,8 +267,6 @@ where
     /// producer.set_value(22.5)?; // constructs Temperature::set(22.5, now_ms) and sends
     /// # Ok(())
     /// # }
-    /// # #[cfg(not(feature = "data-contracts"))]
-    /// # fn main() {}
     /// ```
     pub fn set_value(&self, value: T::Value) -> SyncResult<()> {
         self.set(T::set(value, unix_now_ms()))

aimdb-sync/tests/integration_test.rs

@@ -1,7 +1,9 @@
 //! Integration tests for aimdb-sync
 //!
 //! These tests verify end-to-end functionality of the synchronous API wrapper.
-
+// The whole file exercises `attach()` / `SyncProducer` / `SyncConsumer`, none of
+// which exist without `std`.
+#![cfg(feature = "std")]
 use aimdb_core::{buffer::BufferCfg, AimDbBuilder, DbError};
 use aimdb_sync::AimDbBuilderSyncExt;
 use aimdb_sync::SyncError;

aimdb-sync/tests/settable_integration.rs

@@ -2,7 +2,7 @@
 //! construct via `Settable::set`, produce, and consume end-to-end through the
 //! real sync bridge.
 
-#![cfg(feature = "data-contracts")]
+#![cfg(all(feature = "std", feature = "data-contracts"))]
 
 use aimdb_core::{buffer::BufferCfg, AimDbBuilder};
 use aimdb_data_contracts::{SchemaType, Settable};