fix: resolve compiler warnings on macOS (clang) and Linux - #1140
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Clang on macOS (Apple Silicon, Xcode 15+) emits -Wdangling-assignment
for patterns like:
paramValues[N] = intToString(expr).strValue;
intToString() returns an IntString struct by value; its embedded
strValue[] char array is in a stack temporary that is destroyed at end
of expression, leaving paramValues[N] dangling before the next
pgsql_execute_with_params() call.
Fix: declare a named IntString variable so its lifetime covers the
subsequent call. The compiler warning fires in C99/C11 mode on clang
15+ and in practice the pointer is stable until the stack frame is
reused, but the pattern is formally undefined and must be corrected.
Additional fixes:
- primary_standby.c: remove unused loop counter in crash-recovery
wait loop (variable 'attempts' set but not used).
- cli_formation.c: add missing errors > 0 check in
keeper_cli_formation_create_getopts() matching the pattern in
keeper_cli_formation_drop_getopts(); the variable was correctly
incremented in the default: case but the exit guard was missing
(variable 'errors' set but not used, and a latent logic gap).
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Summary
Clang 15+ on macOS (Apple Silicon / Xcode 15) emits
-Wdangling-assignmentfor a pattern that appears throughout the Citus coordinator and demo-app
code:
intToString()returns anIntStringstruct by value; its embeddedchar strValue[21]array lives in a stack temporary that is destroyed atend of the full-expression, leaving
paramValues[N]dangling before thenext
pgsql_execute_with_params()call. The pointer happens to remainvalid until the next stack frame push on current compilers, but the pattern
is formally undefined and the warning is correct.
Fix: declare a named
IntStringvariable so its lifetime extendsacross the subsequent libpq call.
Changes
coordinator.c(12 sites)-Wdangling-assignmentonintToString().strValueIntStringvariable before assigning toparamValues[]demoapp.c(8 sites)primary_standby.c-Wunused-but-set-variable— loop counterattemptsnever readfor (int attempts = 0;; attempts++)withfor (;;)cli_formation.c-Wunused-but-set-variable—errorsincremented indefault:case but never checkedif (errors > 0) { commandline_help(); exit(); }guard (matches the pattern in the siblingkeeper_cli_formation_drop_getopts; also closes a latent logic gap where unknown options were silently ignored)Testing
make -C src/bin clean allproduces zero warnings on macOS 15 (AppleSilicon, clang 17) after this patch. No behaviour change — the
IntStringstruct is copied to the stack variable; the string contentand the pointer value are identical.