chore(PythonQt): Migrate to Python-3 Unicode API; update generator/wrappers; add opt-in PyString shim; enforce Python ≥ 3 #308

jcfr · 2025-09-25T13:23:54Z

This PR completes the migration to Python 3 string APIs across PythonQt, updates the code generator and generated wrappers, and introduces an opt-in compatibility shim for legacy wrappers.

It removes reliance on PyString_* aliases in PythonQtPythonInclude.h for in-tree sources and makes Unicode usage explicit. The build now errors if Python 2.x is detected.

Summary:

Replace PyString_* with Python-3 equivalents:
- PyString_FromString → PyUnicode_FromString
- PyString_AS_STRING → PyUnicode_AsUTF8
- PyString_AsString → PyUnicode_AsUTF8
- PyString_FromFormat → PyUnicode_FromFormat
- PyString_Check → PyUnicode_Check
Update the generator to emit PyUnicode_*.
Update generated_cpp_* wrappers to use PyUnicode_*.
Add PYTHONQT_USE_PYSTRING_SHIM (default OFF) to alias PyString_FromString → PyUnicode_FromString for older, out-of-tree wrappers.
Enforce Python 3 at build time (hard error on Python 2.x).

mrbean-bremen · 2025-09-25T13:55:59Z

My personal preference would be your second alternative. @usiems - what do you think?

usiems · 2025-09-25T14:53:04Z

Option 2 is good for me. We could also go with option 3, since we might call the next version 4.0 (mostly because we dropped Python 2 support), and this would justify some incompatibilities. But option 2 is certainly safer.

The generated wrappers only seem to use PyString_FromString, so, if we only care about existing generated wrapper code, it would be sufficient to keep just this one define.

By the way, what about the PyInt_ defines? Shouldn't they be replaced, too?

jcfr · 2025-09-25T19:17:12Z

By the way, what about the PyInt_ defines? Shouldn't they be replaced, too?

chore: Migrate integer API usage from PyInt_* to PyLong_* (Python 3) #310

jcfr · 2025-09-25T20:42:38Z

Build / oldschool (rockylinux, 9, debug) (pull_request)

Reported error¹ is unrelated to the proposed changes:

Complete!
Last metadata expiration check: 0:00:55 ago on Thu Sep 25 20:13:12 2025.
Package which-2.21-30.el9_6.x86_64 is already installed.
Error: 
 Problem: package qt5-qtbase-private-devel-5.15.9-11.el9_6.x86_64 from appstream requires cups-devel, but none of the providers can be installed
  - cannot install the best candidate for the job
  - nothing provides cups-libs(x86-32) = 1:2.3.3op2-33.el9_6.1 needed by cups-devel-1:2.3.3op2-33.el9_6.1.i686 from appstream
  - nothing provides cups-libs(x86-64) = 1:2.3.3op2-33.el9_6.1 needed by cups-devel-1:2.3.3op2-33.el9_6.1.x86_64 from appstream
(try to add '--skip-broken' to skip uninstallable packages or '--nobest' to use not only best candidate packages)

https://github.com/MeVisLab/pythonqt/actions/runs/18019484218/job/51273010918?pr=308 ↩

mrbean-bremen · 2025-09-26T04:53:45Z

generated_cpp_50/com_trolltech_qt_core/com_trolltech_qt_core0.cpp

@@ -50,7 +50,7 @@ PythonQtShell_QAbstractAnimation::~PythonQtShell_QAbstractAnimation() {
 void PythonQtShell_QAbstractAnimation::childEvent(QChildEvent*  arg__1)


I wonder if we should remove these older versions of generated code now, instead of adapting them to these changes each time.
Qt versions before 5.9 are not tested at all, and we do not test the checked-in generated code anyway, so we cannot guarantee that it will still work with the current version of PythonQt. Had also a discussion with @usiems about this.

I would tend to remove all checked-in versions except perhaps the 5.15 one. 5.15 can serve as an example of what kind of code is generated, but I would recommend to anyone using that Qt version to re-run the generator even so.

mrbean-bremen · 2025-09-26T04:56:07Z

src/PythonQtPythonInclude.h

 #define PY3K
-// Helper defines to facilitate porting
 #define PyString_FromString PyUnicode_FromString


Maybe add a deprecation warning here? Or would this over-flood the log with warnings?

usiems · 2025-09-26T14:19:52Z

generated_cpp_50/com_trolltech_qt_core/com_trolltech_qt_core0.cpp

@@ -50,7 +50,7 @@ PythonQtShell_QAbstractAnimation::~PythonQtShell_QAbstractAnimation() {
 void PythonQtShell_QAbstractAnimation::childEvent(QChildEvent*  arg__1)


I would tend to remove all checked-in versions except perhaps the 5.15 one. 5.15 can serve as an example of what kind of code is generated, but I would recommend to anyone using that Qt version to re-run the generator even so.

…ring` Make Unicode creation explicit instead of relying on the compatibility macros in `PythonQtPythonInclude.h`. No functional change intended.

This removes dependence on the `PyString_*` shim and documents the Python 3 assumption clearly. No functional change intended.

Port remaining conversions to the Unicode API and drop reliance on the macro alias in `PythonQtPythonInclude.h`. No functional change intended.

…rmat` Format string creation now uses the Unicode API directly. No functional change intended.

Update assertions and type checks to the Unicode API. No functional change intended.

… Python 2.x

…tring` Make Unicode creation explicit instead of relying on the compatibility macros in `PythonQtPythonInclude.h`. No functional change intended.

…_FromString` Make Unicode creation explicit instead of relying on the compatibility macros in `PythonQtPythonInclude.h`. No functional change intended.

This comment was marked as outdated.

Sign in to view

jcfr force-pushed the update-python3-string-handling branch from d2506eb to fcb1caf Compare September 25, 2025 20:10

jcfr mentioned this pull request Sep 25, 2025

chore: Migrate integer API usage from PyInt_* to PyLong_* (Python 3) #310

Merged

jcfr force-pushed the update-python3-string-handling branch from fcb1caf to ed2750d Compare September 25, 2025 20:12

jcfr changed the title ~~chore(PythonQt): Migrate string API usage to Python 3 PyUnicode_*~~ chore(PythonQt): Migrate to Python-3 Unicode API; update generator/wrappers; add opt-in PyString shim; enforce Python ≥ 3 Sep 25, 2025

mrbean-bremen reviewed Sep 26, 2025

View reviewed changes

usiems approved these changes Sep 26, 2025

View reviewed changes

jcfr added 9 commits September 26, 2025 12:46

chore(PythonQt): replace PyString_FromString with `PyUnicode_FromSt…

65ef625

…ring` Make Unicode creation explicit instead of relying on the compatibility macros in `PythonQtPythonInclude.h`. No functional change intended.

chore(PythonQt): replace PyString_AS_STRING with PyUnicode_AsUTF8

ff9a147

This removes dependence on the `PyString_*` shim and documents the Python 3 assumption clearly. No functional change intended.

chore(PythonQt): replace PyString_AsString with PyUnicode_AsUTF8

adaa0f7

Port remaining conversions to the Unicode API and drop reliance on the macro alias in `PythonQtPythonInclude.h`. No functional change intended.

chore(PythonQt): replace PyString_FromFormat with `PyUnicode_FromFo…

eb53f46

…rmat` Format string creation now uses the Unicode API directly. No functional change intended.

chore(PythonQt): replace PyString_Check with PyUnicode_Check

e808b71

Update assertions and type checks to the Unicode API. No functional change intended.

chore(PythonQtPythonInclude, build/python.prf): Report error if using…

c4d00f8

… Python 2.x

chore(generator): replace PyString_FromString with `PyUnicode_FromS…

e676129

…tring` Make Unicode creation explicit instead of relying on the compatibility macros in `PythonQtPythonInclude.h`. No functional change intended.

chore(generated_cpp_*): replace PyString_FromString with `PyUnicode…

e702ff0

…_FromString` Make Unicode creation explicit instead of relying on the compatibility macros in `PythonQtPythonInclude.h`. No functional change intended.

chore: Add support for defining PYTHONQT_USE_PYSTRING_SHIM

e793d1a

hjmjohnson mentioned this pull request Sep 26, 2025

Build & generator cleanup: drop Qt5 wrapper fallbacks, switch CI to Qt 6.10, normalize macOS includes, add qmake toggles, and regenerate wrappers in CI #313

Merged

jcfr force-pushed the update-python3-string-handling branch from ed2750d to e793d1a Compare September 26, 2025 19:46

mrbean-bremen merged commit 5a891f2 into MeVisLab:master Sep 26, 2025
17 checks passed

jcfr deleted the update-python3-string-handling branch September 26, 2025 20:36

jcfr mentioned this pull request Sep 29, 2025

Update Slicer to use Qt6 Slicer/Slicer#6388

Open

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

chore(PythonQt): Migrate to Python-3 Unicode API; update generator/wrappers; add opt-in PyString shim; enforce Python ≥ 3 #308

chore(PythonQt): Migrate to Python-3 Unicode API; update generator/wrappers; add opt-in PyString shim; enforce Python ≥ 3 #308

Uh oh!

jcfr commented Sep 25, 2025 •

edited

Loading

Uh oh!

This comment was marked as outdated.

mrbean-bremen commented Sep 25, 2025

Uh oh!

usiems commented Sep 25, 2025

Uh oh!

jcfr commented Sep 25, 2025

Uh oh!

jcfr commented Sep 25, 2025

Uh oh!

mrbean-bremen Sep 26, 2025

Uh oh!

usiems Sep 26, 2025

Uh oh!

mrbean-bremen Sep 26, 2025

Uh oh!

usiems Sep 26, 2025

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

		@@ -50,7 +50,7 @@ PythonQtShell_QAbstractAnimation::~PythonQtShell_QAbstractAnimation() {
		void PythonQtShell_QAbstractAnimation::childEvent(QChildEvent* arg__1)

chore(PythonQt): Migrate to Python-3 Unicode API; update generator/wrappers; add opt-in PyString shim; enforce Python ≥ 3 #308

chore(PythonQt): Migrate to Python-3 Unicode API; update generator/wrappers; add opt-in PyString shim; enforce Python ≥ 3 #308

Uh oh!

Conversation

jcfr commented Sep 25, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

This comment was marked as outdated.

mrbean-bremen commented Sep 25, 2025

Uh oh!

usiems commented Sep 25, 2025

Uh oh!

jcfr commented Sep 25, 2025

Uh oh!

jcfr commented Sep 25, 2025

Footnotes

Uh oh!

mrbean-bremen Sep 26, 2025

Choose a reason for hiding this comment

Uh oh!

usiems Sep 26, 2025

Choose a reason for hiding this comment

Uh oh!

mrbean-bremen Sep 26, 2025

Choose a reason for hiding this comment

Uh oh!

usiems Sep 26, 2025

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

jcfr commented Sep 25, 2025 •

edited

Loading