gh-136687: allow manually excluding ncurses from the build by duaneg · Pull Request #136696 · python/cpython

duaneg · 2025-07-15T23:43:31Z

Add an option to manually exclude ncurses from the build.

Issue: ./configure misses option to avoid building with ncurses #136687

sobolevn

Please, don't forget to update Doc/using/configure.rst with the new option.

I haven't reviewed the AC code, because I am not an expert there :)

…pping building the python curses module as opposed to not using the system ncurses library. Remove mistakenly repeated test modules section. Document configure option.

duaneg · 2025-07-20T00:13:09Z

Please, don't forget to update Doc/using/configure.rst with the new option.

Ah, thanks! I didn't spot those docs, updated. On review I think it would be better to think of this from the higher-level user perspective of excluding the curses module, rather than the lower-level build perspective of "skipping a system library check". I've renamed the option --disable-curses, instead of disable-ncurses, accordingly.

Although that does prompt the question of whether we should allow excluding other modules at build time. I'm not sure if this has been discussed before or would be considered useful.

I haven't reviewed the AC code, because I am not an expert there :)

As it turns out, I had made a silly mistake and left a copy & pasted chunk of code in there, so I'm glad you didn't review it as yet 🙂

A tip for reviewing: most of the configure.ac changes are making the libncurses checks conditional, and hence mostly just change indentation. If you review them ignoring whitespace the diff is much easier to read.

github-actions · 2026-04-27T00:26:12Z

This PR is stale because it has been open for 30 days with no activity.

serhiy-storchaka

Please resolve conflicts. A large amount of probes was added recently.

serhiy-storchaka · 2026-06-29T17:49:30Z

+AC_ARG_ENABLE([curses], [AS_HELP_STRING(
+                [--disable-curses],
+                [disable building curses module (default is no)])], [
+  AS_VAR_IF([enable_curses], [yes], [Py_CHECK_NCURSES=yes], [Py_CHECK_NCURSES=no])


"curses" or "ncurses"? Inconsistent.

One ("curses") refers to the python module (whether to build it or not), while the other ("ncurses") refers to the system library (whether to look for it or not), so it is the referents that are inconsistent. I thought a higher-level option was better as a configure flag, with the existing system library check variable being essentially an implementation detail.

However, the inconsistency isn't ideal, agreed. If you prefer I'll switch the configure option back to ncurses. Or add a comment, if that would suffice.

The system library is not necessary ncurses.

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>

read-the-docs-community · 2026-07-01T11:54:42Z

Documentation build overview

📚 cpython-previews | 🛠️ Build #33408292 | 📁 Comparing 3a14940 against main (34503f3)

🔍 Preview build

4 files changed

± c-api/module.html
± library/imaplib.html
± using/configure.html
± whatsnew/changelog.html

serhiy-storchaka · 2026-07-01T13:30:33Z

I am sorry, but I changed the configure file again, breaking your PR.

Resolve conflicts in configure.ac/configure: the curses probes added on main (nofilter, has_mouse, is_keypad, is_leaveok, new_prescr, use_screen, use_window, key_defined, term_attrs, define_key, keyok, set_escdelay, set_tabsize, the getmouse X/Open signature check, ESCDELAY/TABSIZE, scr_dump) now sit inside the new --disable-curses (Py_CHECK_NCURSES) conditional, so they are skipped when curses is disabled. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

serhiy-storchaka · 2026-07-01T18:29:04Z

I have resolved conflicts, but the question about ncurses remains.

duaneg · 2026-07-02T08:33:31Z

I have resolved conflicts, but the question about ncurses remains.

Thanks very much and apologies I hadn't done it myself: I got partway last night but ran out of time. Regarding the naming: I am very happy to change the variable name, perhaps something like Py_ENABLE_CURSES would be better?

serhiy-storchaka · 2026-07-02T09:01:53Z

This is not the name of a macro exposed in C. AC_ARG_ENABLE([curses]) already creates enable_curses (yes/no/unset). We can use it.

AC_ARG_ENABLE([curses],
  [AS_HELP_STRING([--disable-curses], [don't build the curses module (default: enabled)])])
AS_VAR_IF([enable_curses], [no], [], [enable_curses=yes])

duaneg · 2026-07-02T09:49:58Z

This is not the name of a macro exposed in C. AC_ARG_ENABLE([curses]) already creates enable_curses (yes/no/unset). We can use it.

Ah, I see, indeed! Thanks 🙂

serhiy-storchaka · 2026-07-18T15:06:37Z

Thanks @duaneg for the patch, and @dilyanpalauzov for the report.

I went with a slightly broader approach in #153992: rather than a boolean --disable-curses, it adds --with-curses=ncursesw|ncurses|curses|no, mirroring --with-readline. --without-curses (i.e. --with-curses=no) does exactly what this PR does — it excludes the curses and _curses_panel modules regardless of what libraries are installed — so the original request is covered. On top of that it lets you pin the backend explicitly and, notably, build against the system's native curses (e.g. on NetBSD or Solaris), which configure previously couldn't reach at all.

Since it supersedes this PR I'd like to close this one — but thank you, it's what prompted the wider change. Could you take a look at #153992 and let me know if anything's missing?

duaneg · 2026-07-18T22:55:41Z

Since it supersedes this PR I'd like to close this one — but thank you, it's what prompted the wider change. Could you take a look at #153992 and let me know if anything's missing?

LGTM and thanks very much for the much more comprehensive fix!

pythongh-136687: allow manually excluding ncurses from the build

763eef8

duaneg requested review from corona10 and erlend-aasland as code owners July 15, 2025 23:43

bedevere-app Bot added the awaiting review label Jul 15, 2025

bedevere-app Bot mentioned this pull request Jul 15, 2025

./configure misses option to avoid building with ncurses #136687

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sobolevn reviewed Jul 19, 2025

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Comment thread Misc/NEWS.d/next/Build/2025-07-16-11-41-43.gh-issue-136687.ob_uIp.rst Outdated

Switch option to "--disable-curses", as this is better considered ski…

0618e05

…pping building the python curses module as opposed to not using the system ncurses library. Remove mistakenly repeated test modules section. Document configure option.

github-actions Bot added the stale Stale PR or inactive for long period of time. label Apr 27, 2026

serhiy-storchaka reviewed Jun 29, 2026

View reviewed changes

Update Doc/using/configure.rst

dc9b543

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>

duaneg requested review from AA-Turner, emmatyping and itamaro as code owners July 1, 2026 11:51

Update configure.ac

a20c004

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>

Use enable_curses as gating variable name

3a14940

github-actions Bot removed the stale Stale PR or inactive for long period of time. label Jul 3, 2026

serhiy-storchaka mentioned this pull request Jul 18, 2026

gh-136687: Add ./configure --with-curses to select the curses backend #153992

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serhiy-storchaka closed this Jul 18, 2026

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