Simplify setup for enabling/disabling allocation recording in the C lib

cli/src/allocations_stubs.rs

@@ -0,0 +1,40 @@
+// In all dev builds, the tree-sitter library is built with the `allocation-tracking`
+// feature enabled. This causes the library to link against a set of externally
+// defined C functions like `ts_record_malloc` and `ts_record_free`. In tests, these
+// are defined to actually keep track of outstanding allocations. But when not running
+// tests, the symbols still need to be defined. This file provides pass-through
+// implementations of all of these functions.
+
+use std::os::raw::c_void;
+
+extern "C" {
+    fn malloc(size: usize) -> *mut c_void;
+    fn calloc(count: usize, size: usize) -> *mut c_void;
+    fn realloc(ptr: *mut c_void, size: usize) -> *mut c_void;
+    fn free(ptr: *mut c_void);
+}
+
+#[no_mangle]
+unsafe extern "C" fn ts_record_malloc(size: usize) -> *const c_void {
+    malloc(size)
+}
+
+#[no_mangle]
+unsafe extern "C" fn ts_record_calloc(count: usize, size: usize) -> *const c_void {
+    calloc(count, size)
+}
+
+#[no_mangle]
+unsafe extern "C" fn ts_record_realloc(ptr: *mut c_void, size: usize) -> *const c_void {
+    realloc(ptr, size)
+}
+
+#[no_mangle]
+unsafe extern "C" fn ts_record_free(ptr: *mut c_void) {
+    free(ptr)
+}
+
+#[no_mangle]
+extern "C" fn ts_toggle_allocation_recording(_: bool) -> bool {
+    false
+}

cli/src/lib.rs

@@ -16,3 +16,6 @@ pub mod web_ui;
 
 #[cfg(test)]
 mod tests;
+
+#[cfg(not(test))]
+mod allocations_stubs;

cli/src/tests/helpers/allocations.rs

@@ -4,6 +4,7 @@
 use lazy_static::lazy_static;
 use spin::Mutex;
 use std::collections::HashMap;
+use std::env;
 use std::os::raw::{c_ulong, c_void};
 
 #[derive(Debug, PartialEq, Eq, Hash)]
@@ -31,9 +32,14 @@ extern "C" {
 
 pub fn start_recording() {
     let mut recorder = RECORDER.lock();
-    recorder.enabled = true;
     recorder.allocation_count = 0;
     recorder.outstanding_allocations.clear();
+
+    if env::var("RUST_TEST_THREADS").map_or(false, |s| s == "1") {
+        recorder.enabled = true;
+    } else {
+        panic!("This test must be run with RUST_TEST_THREADS=1. Use script/test.");
+    }
 }
 
 pub fn stop_recording() {