From 3de99f293a15f6003d09c46b7380f39d2b1a7c87 Mon Sep 17 00:00:00 2001
From: MinchinWeb <w_minchin@hotmail.com>
Date: Tue, 31 Mar 2026 19:24:32 -0600
Subject: [PATCH] Use custom exception for (failing to) overwrite files

---
 pelican/generators.py |  7 ++++---
 pelican/writers.py    | 10 ++++++++--
 2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/pelican/generators.py b/pelican/generators.py
index 65fcb9c3..b7eef104 100644
--- a/pelican/generators.py
+++ b/pelican/generators.py
@@ -30,6 +30,7 @@ from pelican.utils import (
     posixize_path,
     process_translations,
 )
+from pelican.writers import FileOverwriteFailedError
 
 logger = logging.getLogger(__name__)
 
@@ -584,7 +585,7 @@ class ArticlesGenerator(CachingGenerator):
                     page_name=tag.page_name,
                     all_articles=self.articles,
                 )
-            except RuntimeError:
+            except FileOverwriteFailedError:
                 if not tag.slug:
                     logger.info(
                         'Tag "%s" has an invalid slug; skipping writing tag page...',
@@ -615,7 +616,7 @@ class ArticlesGenerator(CachingGenerator):
                     page_name=cat.page_name,
                     all_articles=self.articles,
                 )
-            except RuntimeError:
+            except FileOverwriteFailedError:
                 if not cat.slug:
                     logger.info(
                         'Category "%s" has an invalid slug; skipping writing category page...',
@@ -646,7 +647,7 @@ class ArticlesGenerator(CachingGenerator):
                     page_name=aut.page_name,
                     all_articles=self.articles,
                 )
-            except RuntimeError:
+            except FileOverwriteFailedError:
                 if not aut.slug:
                     logger.info(
                         'Author "%s" has an invalid slug; skipping writing author page...',
diff --git a/pelican/writers.py b/pelican/writers.py
index 009d761a..07aa6d42 100644
--- a/pelican/writers.py
+++ b/pelican/writers.py
@@ -18,6 +18,10 @@ from pelican.utils import (
 logger = logging.getLogger(__name__)
 
 
+class FileOverwriteFailedError(RuntimeError):
+    """Failed to overwrite an existing file."""
+
+
 class Writer:
     def __init__(self, output_path, settings=None):
         self.output_path = output_path
@@ -107,14 +111,16 @@ class Writer:
         """
         if filename in self._overridden_files:
             if override:
-                raise RuntimeError(f"File {filename} is set to be overridden twice")
+                raise FileOverwriteFailedError(
+                    f"File {filename} is set to be overridden twice"
+                )
             logger.info("Skipping %s", filename)
             filename = os.devnull
         elif filename in self._written_files:
             if override:
                 logger.info("Overwriting %s", filename)
             else:
-                raise RuntimeError(f"File {filename} is to be overwritten")
+                raise FileOverwriteFailedError(f"File {filename} is to be overwritten")
         if override:
             self._overridden_files.add(filename)
         self._written_files.add(filename)