[validation only] fix(nix): pin ncurses old glibc symver for cfgetospeed - #2336
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brainrake wants to merge 3 commits into
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[validation only] fix(nix): pin ncurses old glibc symver for cfgetospeed#2336brainrake wants to merge 3 commits into
brainrake wants to merge 3 commits into
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nixpkgs' bumped glibc (2.42) re-versions cfgetospeed, so a freshly built ncurses binds to the new GLIBC_2.42 symbol by default even though nothing about ncurses' own code changed. That breaks the portable CLI bundle on hosts with older glibc (e.g. Ubuntu 24.04's 2.39), since the bundle deliberately excludes glibc itself and relies on the host's. glibc still exports the old (functionally identical) GLIBC_2.17 version of cfgetospeed alongside the new one, so a .symver directive forces ncurses to bind to that instead - verified the patched build against the new glibc drops the GLIBC_2.42 requirement entirely (max symbol version falls back to GLIBC_2.38, matching every other bundled library).
The unconditional .symver directive broke the build on older glibc
(e.g. 2.40, currently on develop): older glibc only exports one
(unversioned-from-this-perspective) definition of cfgetospeed, so
requesting the GLIBC_2.17 version explicitly fails to link
("no symbol version section for versioned symbol"). Only glibc >= 2.42
actually carries both the old and new versioned symbols, so the override
must only apply then.
…compat The .symver approach broke the final link (ncurses' own -Wl,--version-script conflicts with a link-time versioned external symbol reference), and separately, the naive dlvsym-with-fallback first attempt still linked a bare reference to cfgetospeed for its fallback path, which just re-added the GLIBC_2.42 requirement it was meant to avoid. Resolving both dlvsym and its dlsym fallback dynamically (never referencing the bare cfgetospeed identifier in compiled code) sidesteps the linker entirely and degrades gracefully on any glibc, verified by building the patched ncurses against the bumped glibc: no cfgetospeed reference of any kind remains in the dynamic symbol table, and the max GLIBC symbol requirement drops back to 2.38, matching every other library in the bundle.
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Validation result: the `dlvsym`-based ncurses fix works. `ncurses` built successfully against the bumped glibc (2.42) with no `cfgetospeed`/`GLIBC_2.42`/linker errors - confirms the fix resolves the original `GLIBC_2.42' not found` failure at the ncurses level. Overall CI on this PR still fails, but for an unrelated, already-diagnosed reason: this branch is ncurses-only (based on `develop`, no cgal fix), so it still hits the separate pre-existing `boost`/`sfcgal`/postgis cascade that #2332 fixes independently. That's expected here, not a problem with this fix. Closing as validation-only; the real fix will land as its own PR against `develop`. |
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Temporary validation PR targeting #2328's branch to confirm this actually fixes `GLIBC_2.42' not found` (from libncursesw.so.6) with real bumped-nixpkgs artifacts on the existing ubuntu-24.04/ubuntu-latest runners (no runner bump needed — the whole point is the bundle now stays compatible with Ubuntu 24.04, matching what the README claims). Will be closed in favor of a develop-based PR once confirmed green.