set: fix find() returning true on internal error

This code was technically reachable but practically unreachable
(value length not supported). Anyway, return CDADA_E_UNKNOWN.

Reported-By: Claude Opus 4.6 <noreply@anthropic.com>
Signed-off-by: Marc Suñé <marcdevel@gmail.com>

Author: msune

CHANGELOG.md

@@ -19,8 +19,9 @@ Legend:
 - [B] str: align `cdada_str()` invalid-handle behavior with API docs (return `NULL`, not empty string)
 - [B] bbitmap: make `cdada_bbitmap_dump()` set `size_used` in buffered paths too
 - [B] bbitmap: fix corrupted BSD license header in `bbitmap.h`
-- [B] str: fix uint32_t underflow in `cdada_str_rtraverse()` on empty strings
+- [B] str: fix underflow in `cdada_str_rtraverse()` on empty strings
 - [B] list: fix `cdada_list_first()`/`cdada_list_last()` returning `CDADA_SUCCESS` on invalid input
+- [B] set: fix `cdada_set_find()` returning `true` on internal error
 - [O] tests: add coverage for `cdada_strerr()` valid, boundary and high invalid values
 - [O] tests: add `oom_create_test` coverage for create paths (`list`, `map`, `queue`, `set`, `stack`, `str`, `bbitmap`)
 - [O] tests: add coverage for `cdada_str_replace_all()` empty-match invalid input and self-overlap replacement

src/set.cc

@@ -448,7 +448,7 @@ bool cdada_set_find(const cdada_set_t* set, const void* key){
 				return (*m->ops->find)(m, key);
 			default:
 				CDADA_ASSERT(0);
-				return CDADA_E_UNKNOWN;
+				return false;
 		}
 	}catch(...){}