From 728512918e169dd6a84f3c3a2b359c97fcde9b9a Mon Sep 17 00:00:00 2001
From: Andrew Morgan <1342360+anoadragon453@users.noreply.github.com>
Date: Thu, 30 Oct 2025 11:17:35 +0100
Subject: [PATCH] Exclude `.lock` file from `/usr/local` when building docker
 images (#19107)

---
 changelog.d/19107.misc | 1 +
 docker/Dockerfile      | 7 ++++++-
 2 files changed, 7 insertions(+), 1 deletion(-)
 create mode 100644 changelog.d/19107.misc

diff --git a/changelog.d/19107.misc b/changelog.d/19107.misc
new file mode 100644
index 0000000000..38cb9a9b3b
--- /dev/null
+++ b/changelog.d/19107.misc
@@ -0,0 +1 @@
+Prevent uv `/usr/local/.lock` file from appearing in built Synapse docker images.
\ No newline at end of file
diff --git a/docker/Dockerfile b/docker/Dockerfile
index f83486036d..6d10dee1aa 100644
--- a/docker/Dockerfile
+++ b/docker/Dockerfile
@@ -179,7 +179,12 @@ LABEL org.opencontainers.image.licenses='AGPL-3.0-or-later OR LicenseRef-Element
 COPY --from=runtime-deps /install-${TARGETARCH}/etc /etc
 COPY --from=runtime-deps /install-${TARGETARCH}/usr /usr
 COPY --from=runtime-deps /install-${TARGETARCH}/var /var
-COPY --from=builder /install /usr/local
+
+# Copy the installed python packages from the builder stage.
+#
+# uv will generate a `.lock` file when installing packages, which we don't want
+# to copy to the final image.
+COPY --from=builder  --exclude=.lock /install /usr/local
 COPY ./docker/start.py /start.py
 COPY ./docker/conf /conf