Fix mapping geom_hline & geom_vline to discrete variables

Author: has2k1

doc/changelog.qmd

@@ -137,6 +137,12 @@ title: Changelog
 - Fixed bug in [](:class:`~plotnine.geom_histogram`) where mapping to the `weight` aesthetic
   lead to an error. {{< issue 936 >}}
 
+- Fixed bug in [](:class:`~plotnine.geom_vline`) where you could not map the `xintercept`
+  aesthetic to a discrete variable.
+
+- Fixed bug in [](:class:`~plotnine.geom_hline`) where you could not map the `yintercept`
+  aesthetic to a discrete variable.
+
 ## v0.14.5
 (2025-01-02)
 [![](https://zenodo.org/badge/DOI/10.5281/zenodo.14587381.svg)](https://doi.org/10.5281/zenodo.14587381)

plotnine/scales/scale_xy.py

@@ -213,7 +213,7 @@ class scale_x_discrete(scale_position_discrete):
     Discrete x position
     """
 
-    _aesthetics = ["x", "xmin", "xmax", "xend"]
+    _aesthetics = ["x", "xmin", "xmax", "xend", "xintercept"]
 
 
 @dataclass(kw_only=True)
@@ -222,7 +222,7 @@ class scale_y_discrete(scale_position_discrete):
     Discrete y position
     """
 
-    _aesthetics = ["y", "ymin", "ymax", "yend"]
+    _aesthetics = ["y", "ymin", "ymax", "yend", "yintercept"]
 
 
 # Not part of the user API