feat(docker): enable `highlight` for syntax filtering

* Add `py3-pygments` and `highlight` to runtime dependencies for improved
  syntax highlighting support.
* Switch syntax filtering to use shell script with `highlight` v3 for
  better compatibility and output format.
* Update configuration to reference the new filter script, ensuring
  consistent code highlighting in generated content.

3 files changed, 4 insertions, 3 deletions

diff --git a/Dockerfile b/Dockerfile
index 033f8fe..f6317ce 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -18,7 +18,7 @@ FROM alpine:latest AS runtime
 COPY --from=builder /var/www/htdocs/cgit /usr/share/webapps/cgit
 COPY ./filters /usr/lib/cgit/filters
 
-RUN apk --no-cache add lighttpd python3 lua5.4 py3-markdown
+RUN apk --no-cache add lighttpd python3 lua5.4 py3-markdown py3-pygments highlight 
 
 COPY lighttpd.conf /etc/lighttpd/lighttpd.conf
 COPY cgitrc /etc/cgitrc
diff --git a/cgitrc b/cgitrc
index 4a41c0a..20d0ed0 100644
--- a/cgitrc
+++ b/cgitrc
@@ -76,6 +76,7 @@ side-by-side-diffs=0
 
 # needs python-pygments
 # source-filter=/usr/lib/cgit/filters/syntax-highlighting.py
+source-filter=/usr/lib/cgit/filters/syntax-highlighting.sh
 
 # Format markdown, restructuredtext, manpages, text files, and html files through the right converters
 about-filter=/usr/lib/cgit/filters/about-formatting.sh
diff --git a/filters/syntax-highlighting.sh b/filters/syntax-highlighting.sh
index 840bc34..5033f58 100755
--- a/filters/syntax-highlighting.sh
+++ b/filters/syntax-highlighting.sh
@@ -115,7 +115,7 @@ EXTENSION="${BASENAME##*.}"
 # found (for example) on EPEL 6.
 #
 # This is for version 2
-exec highlight --force -f -I -X -S "$EXTENSION" 2>/dev/null
+#exec highlight --force -f -I -X -S "$EXTENSION" 2>/dev/null
 
 # This is for version 3
-#exec highlight --force -f -I -O xhtml -S "$EXTENSION" 2>/dev/null
+exec highlight --force -f -I -O xhtml -S "$EXTENSION" 2>/dev/null