Merge remote-tracking branch 'origin/main' into HEAD

crates/ocs_plugin_api/ARCHITECTURE.md

@@ -44,16 +44,18 @@ The host and each plugin run in separate OS processes. The host re-executes itse
 
 ## Versioning and ABI stability
 
-- `API_VERSION` (currently `4`) is the host's advertised major.
+- `API_VERSION` (currently `5`) is the host's advertised major.
 - `API_VERSION_MIN_SUPPORTED` (currently `2`) is the oldest plugin major the host loads.
-- `OCS_PLUGIN_MAX_API_VERSION` can cap the accepted major at runtime (e.g. `3` to disable V4).
+- `OCS_PLUGIN_MAX_API_VERSION` can cap the accepted major at runtime (e.g. `4` to disable V5).
 - A plugin built against major `N` runs on a host whose major is `>= N` because new vtable entries and enum variants are appended at the end.
 - V4 introduces the **acadrust gate**: plugins targeting API v4 or later must resolve the same `acadrust` source as the host (see [`src/version_info.rs`](src/version_info.rs)).
+- V5 introduces `BuiltinPlugin::on_load`, invoked once after the runner connects.
 
-The runtime enforces two gates:
+The runtime enforces three gates:
 
 1. `ocs_plugin_api_version()` exported by the cdylib must be within `[API_VERSION_MIN_SUPPORTED, effective_max_api_version()]`.
 2. For v4+, `acadrust_sources_compatible(host_acadrust_source(), plugin_acadrust_source)` must be true.
+3. For v4+, the plugin must declare `rustc_version`, and `rustc_versions_compatible(host_rustc_version(), plugin_rustc_version)` must be true.
 
 ---
 
@@ -71,18 +73,21 @@ sequenceDiagram
     PP->>R: spawn --ocs-plugin-runner <socket> <cdylib>
     R->>L: unsafe { load(cdylib_path) }
     L-->>R: Box<dyn BuiltinPlugin>
-    alt API v4
+    alt API v4+
         R->>PP: connect + RunnerHandshake::TokenV4
         PP->>PP: verify token + V4 protocol/API gate
     else API v2/v3
         R->>PP: connect + RunnerHandshake::Token
         PP->>PP: verify token
     end
+    opt API v5+
+        R->>L: on_load(HostApi)
+    end
     PP->>R: HostToPlugin::Request(GetManifest)
     R->>L: manifest()
     L-->>R: PluginManifest { api_version }
     R-->>PP: HostResponse::Manifest
-    PP->>PP: verify api_version + acadrust gate
+    PP->>PP: verify api_version + ABI metadata gates
     alt accepted
         PP-->>PM: success, keep alive
     else rejected
@@ -215,7 +220,7 @@ Broadcasting is V4-gated inside `PluginManager::broadcast_notification`: V2/V3 p
 The crate embeds two JSON blobs at build time:
 
 - **Type registry** (`OUT_DIR/type_registry.json`) — a language-binding-friendly schema for a curated allow-list of `acadrust` types, generated by `serde-reflection` in `build.rs`. See [`src/type_registry.rs`](src/type_registry.rs).
-- **Version info** (`OUT_DIR/version_info.json`) — host version, `ocs_plugin_api` version, `acadrust` version and source, API versions, build timestamp. See [`src/version_info.rs`](src/version_info.rs).
+- **Version info** (`OUT_DIR/version_info.json`) — host version, `ocs_plugin_api` version, `acadrust` version and source, `rustc` version, API versions, build timestamp. See [`src/version_info.rs`](src/version_info.rs).
 
 Both are accessible without enabling the `host` feature.
 
@@ -242,6 +247,7 @@ This is defense-in-depth, not a sandbox: plugins execute native code.
 | Spawn timeout or crash | Spawn fails; plugin not loaded; error surfaced in UI/logs. |
 | Version mismatch | Host refuses plugin before running plugin code. |
 | Acadrust source mismatch (v4+) | Host refuses plugin to avoid binary incompatibilities. |
+| Rustc mismatch (v4+) | Host refuses plugin to avoid cross-compiler ABI crashes. |
 | Unknown notification discriminant | Deserializes to `HostNotification::Unknown`; plugin can ignore. |
 
 ---

crates/ocs_plugin_api/README.md

@@ -9,7 +9,7 @@ cheaply. The runtime host surface is enabled by the `host` feature.
 ## Plugin Architecture
 
 OCS is scriptable and extensible through a versioned plugin API. The API
-supports three major protocol generations: **V2**, **V3**, and **V4**. Each
+supports four major generations: **V2**, **V3**, **V4**, and **V5**. Each
 generation keeps the previous ABI stable by appending new vtable entries and new
 enum variants at the end, so older plugins continue to load on newer hosts.
 
@@ -18,12 +18,17 @@ enum variants at the end, so older plugins continue to load on newer hosts.
 | **V2** | Out-of-process runner | Synchronous commands + interactive point collection (`HostApi::start_interactive`) | Baseline |
 | **V3** | Out-of-process runner | Local cached `document()`/`document_mut()` + shared-memory `DocumentReader`/`document_view` for large reads | New vtable entries appended; new `PluginRequest`/`PluginResponse` variants appended |
 | **V4** | Out-of-process runner over a multiplexed local socket | Full-duplex notifications + asynchronous REPL `ExecuteCode` | New `HostToPluginV4`/`PluginToHostV4` frame layer; `BuiltinPlugin::on_notification` and `start_execute_code` appended to trait |
+| **V5** | V4 multiplexed runner | One-shot `BuiltinPlugin::on_load` initialization | Lifecycle callback appended to `BuiltinPlugin` |
 
 The host controls which generations are accepted at runtime through
-`OCS_PLUGIN_MAX_API_VERSION` (e.g. `2` for V2-only mode, `3` to disable V4). The
-current host advertises [`API_VERSION = 4`](src/manifest.rs) and supports plugins
+`OCS_PLUGIN_MAX_API_VERSION` (e.g. `2` for V2-only mode, `4` to disable V5). The
+current host advertises [`API_VERSION = 5`](src/manifest.rs) and supports plugins
 back to `API_VERSION_MIN_SUPPORTED = 2`.
 
+V5 calls `BuiltinPlugin::on_load` once after the runner connects and before the
+first user command. Plugins can cache `HostApi::plugin_request_sender()` there
+for worker-thread access. A panic in the callback fails plugin loading.
+
 ### High-level layout
 
 ```mermaid
@@ -263,7 +268,7 @@ static MANIFEST: PluginManifest = PluginManifest {
     name: "Hello Plugin",
     version: "0.1.0",
     description: "A minimal example plugin.",
-    api_version: ApiVersion { major: 4 },
+    api_version: ApiVersion::CURRENT,
     ribbon_order: 100,
     xdata_apps: &[],
     command_prefixes: &["HELLO"],

crates/ocs_plugin_api/build.rs

@@ -2,6 +2,7 @@ use std::collections::BTreeMap;
 use std::env;
 use std::fs;
 use std::path::{Path, PathBuf};
+use std::process::Command;
 use std::time::SystemTime;
 
 use cargo_lock::Lockfile;
@@ -383,12 +384,27 @@ fn generate_version_info(out_dir: &Path) {
         .find(|p| p.name.as_str() == "acadrust")
         .expect("acadrust package in Cargo.lock");
 
+    let rustc = env::var_os("RUSTC").unwrap_or_else(|| "rustc".into());
+    let rustc_version = Command::new(rustc)
+        .arg("--version")
+        .output()
+        .ok()
+        .and_then(|o| {
+            if o.status.success() {
+                Some(String::from_utf8_lossy(&o.stdout).trim().to_string())
+            } else {
+                None
+            }
+        })
+        .unwrap_or_default();
+
     let info = serde_json::json!({
         "ocs_version": ocs.version.to_string(),
         "ocs_plugin_api_version": env!("CARGO_PKG_VERSION"),
         "acadrust_version": acadrust.version.to_string(),
         "acadrust_source": acadrust.source.as_ref().map(|s| s.to_string()),
-        "api_version": 4,
+        "rustc_version": rustc_version,
+        "api_version": 5,
         "api_version_min_supported": 2,
         "build_timestamp": build_timestamp,
     });

crates/ocs_plugin_api/src/host.rs

@@ -299,6 +299,14 @@ pub trait BuiltinPlugin: Send + Sync {
     /// the V4 runner guarantees it is only called for plugins that report
     /// API major 4 or newer.
     fn on_notification(&mut self, _command_id: Option<u64>, _notification: HostNotification) {}
+
+    /// Lifecycle callback invoked once after the runner connects. The plugin
+    /// receives the active document tab's `HostApi` so it can set up worker
+    /// threads or cache `plugin_request_sender()` before any user command runs.
+    ///
+    /// Added in API v5. The runner only calls this for plugins that report API
+    /// major 5 or newer.
+    fn on_load(&mut self, _host: &mut dyn HostApi) {}
 }
 
 /// A point-driven interactive command a plugin starts via

crates/ocs_plugin_api/src/manifest.rs

@@ -17,8 +17,9 @@
 /// `document()` / `document_mut()` to local cached copies for out-of-process
 /// plugins and appends `document_reader` / `document_view` at the end of the
 /// vtable so API v2 plugins keep working. v4 adds full-duplex notifications on
-/// a multiplexed socket while leaving the V2/V3 ABI and protocol untouched.
-pub const API_VERSION: u32 = 4;
+/// a multiplexed socket while leaving the V2/V3 ABI and protocol untouched. v5
+/// adds the `BuiltinPlugin::on_load` lifecycle callback.
+pub const API_VERSION: u32 = 5;
 
 /// Oldest plugin API major the current host still loads. This keeps previously
 /// compiled cdylibs usable as long as their vtable layout is a prefix of the
@@ -26,9 +27,8 @@ pub const API_VERSION: u32 = 4;
 pub const API_VERSION_MIN_SUPPORTED: u32 = 2;
 
 /// Environment variable that caps the API major accepted by the host at
-/// runtime. Set to `3` to disable V4 plugins while keeping V2/V3 plugins
-/// working; set to `2` for V2-only mode. The same mechanism will apply to
-/// future API majors.
+/// runtime. Set to `4` to disable V5 plugins, `3` to disable V4, or `2` for
+/// V2-only mode.
 pub const MAX_API_VERSION_ENV: &str = "OCS_PLUGIN_MAX_API_VERSION";
 
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]

crates/ocs_plugin_api/src/runner.rs

@@ -56,15 +56,33 @@ pub fn run(socket_name: &str, cdylib_path: &Path) -> Result<(), Box<dyn std::err
 
     if version >= 4 {
         let client = V4Client::connect_handshake(socket_name, &token)?;
+        if version >= 5 {
+            invoke_on_load(&mut *plugin, &client, &interactive)?;
+        }
         run_v4(&mut *plugin, &interactive, client)
     } else {
         let client = IpcClient::connect(socket_name)?;
         eprintln!("[runner] connected to host");
         client.send_handshake(&token)?;
+        // V2/V3 plugins receive HostApi only during dispatch, so on_load is not
+        // meaningful there; skip it to keep the old protocol unchanged.
         run_v3(&*plugin, &interactive, client)
     }
 }
 
+fn invoke_on_load(
+    plugin: &mut dyn BuiltinPlugin,
+    client: &V4Client,
+    interactive: &InteractiveRegistry,
+) -> Result<(), Box<dyn std::error::Error>> {
+    let mut proxy = client.plugin_host_api(0, interactive.clone());
+    std::panic::catch_unwind(std::panic::AssertUnwindSafe(|| {
+        plugin.on_load(&mut proxy)
+    }))
+    .map_err(|_| std::io::Error::other("plugin on_load() panicked"))?;
+    Ok(())
+}
+
 fn run_v3(
     plugin: &dyn BuiltinPlugin,
     interactive: &InteractiveRegistry,

crates/ocs_plugin_api/src/version_info.rs

@@ -11,6 +11,12 @@
 //! `acadrust` source with its own via [`acadrust_sources_compatible`]. Two
 //! sources are considered compatible only when they resolve to the same 40
 //! character git commit hash.
+//!
+//! The rustc version string is also recorded because Rust has no stable ABI:
+//! a plugin built with a different compiler than the host can pass simple calls
+//! and then crash the runner on compound types. For API v4 and later the host
+//! can compare the plugin's declared rustc with its own via
+//! [`rustc_versions_compatible`].
 
 use std::sync::OnceLock;
 
@@ -26,6 +32,7 @@ pub fn get_embedded_version_info_json() -> &'static str {
 #[derive(Debug, Clone)]
 struct VersionInfo {
     acadrust_source: String,
+    rustc_version: String,
 }
 
 pub const ACADRUST_GATE_API_VERSION: u32 = 4;
@@ -48,6 +55,8 @@ fn parsed_version_info() -> &'static VersionInfo {
     INFO.get_or_init(|| VersionInfo {
         acadrust_source: json_string_value(EMBEDDED_VERSION_INFO_JSON, "acadrust_source")
             .unwrap_or_default(),
+        rustc_version: json_string_value(EMBEDDED_VERSION_INFO_JSON, "rustc_version")
+            .unwrap_or_default(),
     })
 }
 
@@ -56,6 +65,30 @@ pub fn host_acadrust_source() -> &'static str {
     &parsed_version_info().acadrust_source
 }
 
+/// Returns the host's `rustc --version` output.
+pub fn host_rustc_version() -> &'static str {
+    &parsed_version_info().rustc_version
+}
+
+/// Returns whether two `rustc --version` outputs are considered compatible.
+///
+/// The full version line (e.g. "rustc 1.98.0 (hash date)") is compared
+/// token-by-token after normalising whitespace. This is intentionally strict:
+/// Rust has no stable ABI, so even the same nominal compiler built in different
+/// environments can produce incompatible layouts.
+pub fn rustc_versions_compatible(a: &str, b: &str) -> bool {
+    if a.is_empty() || b.is_empty() {
+        return false;
+    }
+    let a_tokens: Vec<&str> = a.split_whitespace().collect();
+    let b_tokens: Vec<&str> = b.split_whitespace().collect();
+    a_tokens.len() == b_tokens.len()
+        && a_tokens
+            .iter()
+            .zip(b_tokens)
+            .all(|(a, b)| a.eq_ignore_ascii_case(b))
+}
+
 /// Extracts the full git commit hash from a Cargo source.
 pub fn acadrust_source_hash(source: &str) -> Option<&str> {
     let hash = source.rsplit('#').next()?;
@@ -85,6 +118,7 @@ mod tests {
         let value: serde_json::Value = serde_json::from_str(json).expect("valid JSON");
         assert!(value.get("ocs_version").is_some());
         assert!(value.get("acadrust_source").is_some());
+        assert!(value.get("rustc_version").is_some());
     }
 
     #[test]
@@ -96,6 +130,7 @@ mod tests {
             "ocs_plugin_api_version",
             "acadrust_version",
             "acadrust_source",
+            "rustc_version",
             "api_version",
             "api_version_min_supported",
             "build_timestamp",
@@ -112,7 +147,7 @@ mod tests {
             value["ocs_plugin_api_version"].as_str(),
             Some(env!("CARGO_PKG_VERSION"))
         );
-        assert_eq!(value["api_version"].as_i64(), Some(4));
+        assert_eq!(value["api_version"].as_i64(), Some(5));
         assert_eq!(value["api_version_min_supported"].as_i64(), Some(2));
 
         // acadrust_version should have a patch component (e.g. "0.4.0").
@@ -125,6 +160,45 @@ mod tests {
         assert!(!host_acadrust_source().is_empty());
     }
 
+    #[test]
+    fn host_rustc_version_is_non_empty() {
+        assert!(!host_rustc_version().is_empty());
+    }
+
+    #[test]
+    fn rustc_version_comparison_is_strict() {
+        assert!(rustc_versions_compatible(
+            "rustc 1.98.0 (abc123 2026-01-01)",
+            "rustc 1.98.0 (abc123 2026-01-01)"
+        ));
+        assert!(!rustc_versions_compatible(
+            "rustc 1.96.0 (def456 2025-11-01)",
+            "rustc 1.98.0 (abc123 2026-01-01)"
+        ));
+    }
+
+    #[test]
+    fn rustc_version_comparison_normalises_whitespace() {
+        assert!(rustc_versions_compatible(
+            "rustc  1.98.0  (abc123  2026-01-01)",
+            "rustc 1.98.0 (abc123 2026-01-01)"
+        ));
+    }
+
+    #[test]
+    fn rustc_version_comparison_rejects_empty() {
+        assert!(!rustc_versions_compatible("", "rustc 1.98.0"));
+        assert!(!rustc_versions_compatible("rustc 1.98.0", ""));
+        assert!(!rustc_versions_compatible("", ""));
+    }
+
+    #[test]
+    fn rustc_version_comparison_rejects_collapsed_tokens() {
+        // A concatenated version must not accidentally match a spaced one.
+        assert!(!rustc_versions_compatible("rustc 1.98.0", "rustc1.98.0"));
+        assert!(!rustc_versions_compatible("rustc1.98.0", "rustc 1.98.0"));
+    }
+
     #[test]
     fn dependency_gate_starts_at_api_v4() {
         assert!(!uses_acadrust_gate(3));