From e33bd8799094e989ba16fdba5b528d9595eab8a8 Mon Sep 17 00:00:00 2001
From: Iulia Dumitru <iuliadmtru@gmail.com>
Date: Thu, 6 Jul 2023 17:41:21 +0300
Subject: [PATCH] Add rule for indexing by `threadid()`

---
 threads/index_by_threadid.jl  | 28 ++++++++++++++++++++++++++++
 threads/index_by_threadid.yml | 21 +++++++++++++++++++++
 2 files changed, 49 insertions(+)
 create mode 100644 threads/index_by_threadid.jl
 create mode 100644 threads/index_by_threadid.yml

diff --git a/threads/index_by_threadid.jl b/threads/index_by_threadid.jl
new file mode 100644
index 0000000..8105054
--- /dev/null
+++ b/threads/index_by_threadid.jl
@@ -0,0 +1,28 @@
+using Base.Threads
+
+states = zeros(10)
+Threads.@spawn for i = 1:10
+    # ruleid: index-by-threadid
+    tid = Threads.threadid()
+    old_val = states[tid]
+    new_val = old_val + i
+    states[tid] = new_val
+end
+
+@spawn begin
+    # ruleid: index-by-threadid
+    tid = threadid()
+    val = states[tid]
+    states[tid] = val + 1
+end
+
+Threads.@spawn for i = 1:10
+    # ruleid: index-by-threadid
+    val = states[threadid()]
+end
+
+
+Threads.@spawn for i = 1:10
+    # ruleid: index-by-threadid
+    val = states[Threads.threadid()]
+end
diff --git a/threads/index_by_threadid.yml b/threads/index_by_threadid.yml
new file mode 100644
index 0000000..4210ca1
--- /dev/null
+++ b/threads/index_by_threadid.yml
@@ -0,0 +1,21 @@
+rules:
+  - id: index-by-threadid
+    pattern-either:
+      - pattern: |
+          $TID = Threads.threadid()
+          ...
+          $X = $S[$TID]
+      - pattern: |
+          $TID = threadid()
+          ...
+          $X = $S[$TID]
+      - pattern: $S[threadid()]
+      - pattern: $S[Threads.threadid()]
+    message: Indexing by `threadid()` may cause race conditions and should be avoided.
+    metadata:
+      references:
+        - https://julialang.netlify.app/previews/pr1914/blog/2023/06/psa-dont-use-threadid/
+      license: LGPL
+    languages:
+      - julia
+    severity: WARNING