fix: lock lazy decompressor pool init on Julia < 1.12

Project.toml

@@ -1,6 +1,6 @@
 name = "CommonDataFormat"
 uuid = "a9737db6-c05c-4e48-868b-6bc41491d9d9"
-version = "0.4.2"
+version = "0.4.3"
 authors = ["Beforerr <zzj956959688@gmail.com> and contributors"]
 
 [workspace]

src/CommonDataFormat.jl

@@ -21,15 +21,20 @@ export is_record_varying
         return chnl
     end
 else
+    # First called inside `@threads`; unlocked, racing workers each build a pool and one
+    # deadlocks returning its decompressor to the other, already full, pool.
     const _decompressors = Ref{Union{Channel{Decompressor},Nothing}}(nothing)
+    const _decompressors_lock = ReentrantLock()
     function decompressors()
-        if _decompressors[] === nothing
-            n_ch = nthreads()
-            chnl = Channel{Decompressor}(n_ch)
-            foreach(i -> put!(chnl, Decompressor()), 1:n_ch)
-            _decompressors[] = chnl
+        @lock _decompressors_lock begin
+            if _decompressors[] === nothing
+                n_ch = nthreads()
+                chnl = Channel{Decompressor}(n_ch)
+                foreach(i -> put!(chnl, Decompressor()), 1:n_ch)
+                _decompressors[] = chnl
+            end
+            return _decompressors[]
         end
-        return _decompressors[]
     end
     __init__() = _decompressors[] = nothing
 end