Enable or disable the Maven build cache extension: the switches that work

The Apache Maven Build Cache Extension has command-line switches to turn it off, skip the lookup, stop talking to the server, or stop uploading. Here is what each one did in a real run against a self-hosted cache (FosterStack Cache 0.2.1, Maven 3.10.0, extension 1.2.3).

The short answer

-Dmaven.build.cache.enabled=false turns the cache off for that build.
-Dmaven.build.cache.skipCache=true ignores stored results and builds fully.
-Dmaven.build.cache.remote.enabled=false stops all contact with the server.
-Dmaven.build.cache.remote.save.enabled=false lets the build download but never upload.

What we ran

A small Maven project with the extension set up as described in Maven remote build cache setup. Every build used a fresh copy of the project and an empty local build cache, so the only shared thing was the server. All seven builds ended with BUILD SUCCESS.

Build	Added to the command	Result
1	nothing (empty server)	Compiled, and saved the result to the server
2	nothing (another machine)	Restored from the cache, no compile
3	`-Dmaven.build.cache.enabled=false`	Compiled. The cache was off
4	`-Dmaven.build.cache.skipCache=true`	Compiled, although a result was stored
5	`-Dmaven.build.cache.remote.enabled=false`	Compiled. It did not ask the server at all
6	`-Dmaven.build.cache.remote.save.enabled=false` (empty server)	Compiled. The server still had 0 entries
7	same as 6, again	Compiled again, because nothing was ever stored

What Maven prints for each switch

enabled=false:
[INFO] Cache disabled by command line flag, project will be built fully and not cached

skipCache=true:
[INFO] Project demo:demo is marked as requiring force rebuild, will skip lookup in build cache

With remote.enabled=false there was no download attempt in the log. With remote.save.enabled=false the build still looked in the server, found nothing, and built locally.

"Error downloading cache item" on a normal miss

The first build against an empty server printed this line, and it still succeeded:

[ERROR] Error downloading cache item: http://127.0.0.1:18160//v1.1/demo/demo/ebb9bceba2f7a6bc/buildinfo.xml
[INFO] Remote cache is incomplete or missing, trying local build for demo:demo

In our run this was an ordinary miss: nothing was stored under that key yet, so Maven built the project itself. The next line says so. If you see this line on a cache that you know holds the result, check the address, the login and the proxy: see Maven build cache not restoring.

Which one to use

A suspect build: enabled=false rules the cache out completely.
Make sure you build fresh: skipCache=true, for example for a release build.
Working offline or off the VPN: remote.enabled=false, so Maven does not wait on a server it cannot reach.
Developers read, CI writes: remote.save.enabled=false on developer machines. The same idea for Gradle is on CI writes, developers read. A read-only login on the server enforces it.

The same job for Gradle is on enable or disable the Gradle build cache.

Run on Maven 3.10.0 with maven-build-cache-extension 1.2.3 and FosterStack Cache 0.2.1, macOS (arm64).