When a string object is interned via_PyUnicode_InternInPlace(), its "state.interned" field is set. Afterward, subsequent calls to_PyUnicode_InternInPlace() will skip that string. The problem is that some strings may be used in multiple interpreters, which each have their own interned dict. The string is shared between the interpreters, along with its "state.interned" field. That means the string will only be interned in the first interpreter where_PyUnicode_InternInPlace() is called (ignoring races in the function, e.g.gh-106930).

We need to fix it so one of the following is true:

• there should be one global interned "dict" shared by all interpreters (we tried this already and it is very tricky)
• strings are always interned in every interpreter, regardless of the "state.interned" value

Linked PRs

• gh-106931: Intern Statically Allocated Strings Globally #107272
• [3.12] gh-106931: Intern Statically Allocated Strings Globally (gh-107272) #107358
• gh-106931: Fix the WASM Buildbots #107362
• [3.12] gh-106931: Intern Statically Allocated Strings Globally (gh-107272) #110713