From e59be444e99b9eeb7da9c5084c3f7827836b568b Mon Sep 17 00:00:00 2001
From: mikkeldamsgaard <krulimut@gmail.com>
Date: Thu, 12 Mar 2026 00:13:37 +0100
Subject: [PATCH] fix: replace --mount=type=cache with dependency layer caching
 in Dockerfiles

--mount=type=cache does not persist across GitHub Actions runners,
causing full recompilation on every release build. Reintroduce the
"empty main" trick for reliable Docker layer caching.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 CHANGELOG.md   |  3 +++
 Dockerfile     | 10 +++++-----
 jyq.Dockerfile | 10 +++++-----
 3 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index cf72282..f9cde8f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Auto-tag workflow: CI automatically creates a git tag when `Cargo.toml` version changes on main, triggering the release workflow.
 - `/release` skill for Claude Code: guided release preparation with version determination, confirmation, and PR creation.
 
+### Fixed
+- Replaced Dockerfile `--mount=type=cache` with dependency layer caching ("empty main" trick) for reliable Docker build caching in GitHub Actions, where `--mount=type=cache` does not persist across runners.
+
 ## [1.2.0] - 2026-03-11
 
 ### Added
diff --git a/Dockerfile b/Dockerfile
index 115aade..50428e5 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -3,13 +3,13 @@ ARG VERSION=dev
 RUN apk add --no-cache musl-dev openssl-dev openssl-libs-static perl
 WORKDIR /src
 COPY Cargo.toml Cargo.lock ./
-COPY . .
-RUN --mount=type=cache,target=/usr/local/cargo/registry \
-    --mount=type=cache,target=/src/target \
+RUN mkdir src && echo 'fn main() {}' > src/main.rs && \
     cargo build --release && \
-    cp target/release/initium /initium
+    rm -rf src target/release/deps/initium* target/release/initium*
+COPY . .
+RUN cargo build --release
 FROM scratch
 COPY --from=builder /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/
-COPY --from=builder /initium /initium
+COPY --from=builder /src/target/release/initium /initium
 USER 65534:65534
 ENTRYPOINT ["/initium"]
diff --git a/jyq.Dockerfile b/jyq.Dockerfile
index 9c8ab29..63e5c07 100644
--- a/jyq.Dockerfile
+++ b/jyq.Dockerfile
@@ -3,14 +3,14 @@ ARG VERSION=dev
 RUN apk add --no-cache musl-dev openssl-dev openssl-libs-static perl
 WORKDIR /src
 COPY Cargo.toml Cargo.lock ./
-COPY . .
-RUN --mount=type=cache,target=/usr/local/cargo/registry \
-    --mount=type=cache,target=/src/target \
+RUN mkdir src && echo 'fn main() {}' > src/main.rs && \
     cargo build --release && \
-    cp target/release/initium /initium
+    rm -rf src target/release/deps/initium* target/release/initium*
+COPY . .
+RUN cargo build --release
 FROM alpine:3.21
 RUN apk add --no-cache jq yq ca-certificates \
     && rm -rf /var/cache/apk/*
-COPY --from=builder /initium /initium
+COPY --from=builder /src/target/release/initium /initium
 USER 65534:65534
 ENTRYPOINT ["/initium"]