0.1.2

Released on 2026-10-05.

Serc 0.1.2 improves CPython bytecode compatibility and speeds up compilation and
serialization.

Bug fixes

• Preserve shared returns and cleanup exits when constant-true assertions are
  folded on Python 3.12 (#975;
  #975)
• Match CPython control flow when optimization removes nested assertions or
  branch prefixes (#989;
  #989) (#991;
  #991) (#998;
  #998) (#1005;
  #1005) (#1027;
  #1027)
• Match CPython control flow in coroutines and nested iterators after assertion
  removal (#995; #995)
  (#1016; #1016)
• Preserve implicit returns after optimization erases terminal loop assertions
  (#1012; #1012)
• Match CPython loop bytecode when optimization removes else assertions after
  assignments, comprehensions, and inner loops (#1004;
  #1004) (#1006;
  #1006) (#1007;
  #1007) (#1008;
  #1008)
• Match CPython loop bytecode after assertion removal inside try blocks and
  context managers (#993;
  #993) (#999;
  #999) (#1019;
  #1019) (#1020;
  #1020)
• Match CPython loop bytecode in coroutines and async loops after awaits and
  assertion removal (#994;
  #994) (#1002;
  #1002) (#1010;
  #1010) (#1011;
  #1011)
• Match CPython cleanup ordering when break or continue exits through
  finally blocks (#977;
  #977) (#981;
  #981) (#1022;
  #1022)
• Match CPython exception tables for returns and conditional cleanup in
  finally blocks (#982;
  #982) (#983;
  #983) (#984;
  #984)
• Match CPython exception tables for returns and nested cleanup in async context
  managers (#985; #985)
• Match CPython iterator cleanup when finally blocks call methods or local
  callables (#986; #986)
  (#992; #992)
• Match CPython local-variable loads after conditional cleanup, try/else
  breaks, and exception-handler exits (#976;
  #976) (#1000;
  #1000) (#1003;
  #1003) (#1009;
  #1009)
• Match CPython local-variable loads after conditional loops in finally blocks
  (#1001; #1001)
• Match CPython exception tables for conditional tuple returns inside try
  blocks (#1015; #1015)
• Match CPython bytecode and source locations for exception-handler cleanup and
  closure setup (#979; #979)
  (#980; #980)
• Match CPython exception tables when break or return exits nested exception
  handlers and finally blocks (#1023;
  #1023) (#1024;
  #1024) (#1025;
  #1025) (#1026;
  #1026)
• Match CPython cleanup for sequence patterns with multiple wildcards and match
  statements inside unnamed exception handlers (#1018;
  #1018) (#1021;
  #1021)
• Keep later global references independent from temporary comprehension targets
  (#972; #972)
• Calculate the correct stack size for later except* handlers containing
  calls, suspension, or nested cleanup on Python 3.14 and 3.15
  (#974; #974)
• Compile deeply nested statement suites without overflowing small thread stacks
  (#971; #971)
• Preserve the final operand’s source line in chained None comparisons on
  Python 3.12 and 3.13 (#973;
  #973)
• Match CPython startup string interning and marshal identity on Linux for the
  documented native reference profile across Python 3.12 through 3.15
  (#978; #978)
• Match CPython constant tables and bytecode when folding Boolean expressions
  and starred collection literals (#987;
  #987) (#988;
  #988)

Performance

• Speed up marshal serialization (#930;
  #930) (#931;
  #931) (#932;
  #932) (#962;
  #962)
• Reduce compilation overhead (#948;
  #948) (#964;
  #964)
• Speed up compilation of annotation-heavy code (#996;
  #996) (#997;
  #997) (#1013;
  #1013)
• Reduce memory allocations during compilation (#1017;
  #1017)
• Reduce repeated work when compiling folded constants (#1014;
  #1014)
• Speed up source nesting validation (#930;
  #930) (#931;
  #931) (#932;
  #932)