Split launcher/daemon terminology from client/server (#5135)

We always had two clients and two servers: previously
`mill.main.client`/`mill.runner.client` and
`mill.main.server`/`mill.runner.server`, and when you saw `client` or
`server` it was never clear which one you were referring to.
Furthermore, `client`/`server` was always very confusing since it brings
to mind HTTP clients/server or network client/servers which Mill is not.

In `main` with #5062 we started using `client`/`server` to refer to the
underlying protocol, while `launcher`/`daemon` referred to the
high-level JVM processes. These are much better names for the two
concepts, and avoid conflicting with the `client`/`server` terms used
for the underlying protocol components

This PR standardizes our terminology to use `launcher`/`daemon`
throughout the codebase, with the `.fork`/`.server` names in our
integration tests renamed to `.nodaemon`/`.daemon`

Author: lihaoyi

.github/workflows/run-tests.yml

@@ -21,7 +21,7 @@
 #      - uses: sbt/setup-sbt@v1
 #
 #
-#      - run:  ./mill 'integration.migrating[init].local.server.testOnly' mill.integration.MillInitSbtGatlingTests
+#      - run:  ./mill 'integration.migrating[init].local.daemon.testOnly' mill.integration.MillInitSbtGatlingTests
 #
 
 
@@ -91,15 +91,15 @@ jobs:
           # Run these with Mill native launcher as a smoketest
         include:
           - os: ubuntu-24.04-arm
-            millargs: "'example.thirdparty[fansi].native.server'"
+            millargs: "'example.thirdparty[fansi].native.daemon'"
             java-version: 17
 
           - os: macos-latest
-            millargs: "'example.thirdparty[acyclic].native.server'"
+            millargs: "'example.thirdparty[acyclic].native.daemon'"
             java-version: 11
 
           - os: macos-13
-            millargs: "'example.thirdparty[jimfs].native.server'"
+            millargs: "'example.thirdparty[jimfs].native.daemon'"
             java-version: 11
     steps:
       - uses: actions/checkout@v4
@@ -154,88 +154,88 @@ jobs:
             install-sbt: false
 
           - java-version: 17
-            millargs: "example.javalib.__.local.server"
+            millargs: "example.javalib.__.local.daemon"
             install-android-sdk: false
             install-sbt: false
 
           - java-version: 17
-            millargs: "example.kotlinlib.__.local.server"
+            millargs: "example.kotlinlib.__.local.daemon"
             install-android-sdk: false
             install-sbt: false
 
           # Run this one using `.native` as a smoketest. Also make sure the java-version
           # is the same as that used in the `build-linux` job to avoid diverging code
           # hashes (https://github.com/com-lihaoyi/mill/pull/4410)
           - java-version: 11
-            millargs: "example.scalalib.__.native.server"
+            millargs: "example.scalalib.__.native.daemon"
             install-android-sdk: false
             install-sbt: false
 
           - java-version: 17
-            millargs: "'example.androidlib.__.local.server'"
+            millargs: "'example.androidlib.__.local.daemon'"
             install-android-sdk: true
             install-sbt: false
 
           - java-version: 17
-            millargs: "'example.thirdparty[androidtodo].local.server'"
+            millargs: "'example.thirdparty[androidtodo].local.daemon'"
             install-android-sdk: true
             install-sbt: false
 
           - java-version: 17
-            millargs: "'example.thirdparty[android-endless-tunnel].local.server'"
+            millargs: "'example.thirdparty[android-endless-tunnel].local.daemon'"
             install-android-sdk: true
             install-sbt: false
 
           - java-version: 17
-            millargs: "'{example,integration}.migrating.__.local.server'"
+            millargs: "'{example,integration}.migrating.__.local.daemon'"
             install-android-sdk: false
             install-sbt: true
 
           - java-version: 17
-            millargs: "'example.{pythonlib,javascriptlib}.__.local.server'"
+            millargs: "'example.{pythonlib,javascriptlib}.__.local.daemon'"
             install-android-sdk: false
             install-sbt: false
 
           - java-version: 11
-            millargs: "'example.thirdparty[{mockito,commons-io}].local.server'"
+            millargs: "'example.thirdparty[{mockito,commons-io}].local.daemon'"
             install-android-sdk: false
             install-sbt: false
 
           - java-version: 17
-            millargs: "'example.thirdparty[{netty,gatling}].local.server'"
+            millargs: "'example.thirdparty[{netty,gatling}].local.daemon'"
             install-android-sdk: false
             install-sbt: false
 
           - java-version: '17'
-            millargs: "'example.thirdparty[arrow].local.server'"
+            millargs: "'example.thirdparty[arrow].local.daemon'"
             install-android-sdk: false
             install-sbt: false
 
           - java-version: 11
-            millargs: "'example.{cli,fundamentals,depth,extending}.__.local.server'"
+            millargs: "'example.{cli,fundamentals,depth,extending}.__.local.daemon'"
             install-android-sdk: false
             install-sbt: false
 
           - java-version: 11
-            millargs: "'integration.{failure,feature,ide}.__.packaged.server'"
+            millargs: "'integration.{failure,feature,ide}.__.packaged.daemon'"
             install-android-sdk: false
             install-sbt: false
 
             # run this specifically in `native` mode to make sure our non-JVM native image
             # launcher is able to bootstrap everything necessary without a JVM installed
           - java-version: 17
-            millargs: "'integration.bootstrap[no-java-bootstrap].native.server'"
+            millargs: "'integration.bootstrap[no-java-bootstrap].native.daemon'"
             install-android-sdk: false
 
             # These invalidation tests need to be exercised in both execution modes
             # to make sure they work with and without -i/--no-server being passed
           - java-version: 17
-            millargs: "'integration.invalidation.__.packaged.fork'"
+            millargs: "'integration.invalidation.__.packaged.nodaemon'"
             install-android-sdk: false
             install-sbt: false
 
           - java-version: 17
-            millargs: "'integration.invalidation.__.packaged.server'"
+            millargs: "'integration.invalidation.__.packaged.daemon'"
             install-android-sdk: false
             install-sbt: false
 
@@ -264,23 +264,23 @@ jobs:
             install-sbt: false
 
           - java-version: 11
-            millargs: '"example.scalalib.{basic,publishing}.__.local.fork"'
+            millargs: '"example.scalalib.{basic,publishing}.__.local.nodaemon"'
             install-sbt: false
 
           - java-version: 11
-            millargs: '"example.migrating.{scalalib,javalib}.__.local.fork"'
+            millargs: '"example.migrating.{scalalib,javalib}.__.local.nodaemon"'
             install-sbt: true
 
           - java-version: 17
-            millargs: "'integration.{feature,failure}.__.packaged.fork'"
+            millargs: "'integration.{feature,failure}.__.packaged.nodaemon'"
             install-sbt: false
 
           - java-version: 11 # Run this with Mill native launcher as a smoketest
-            millargs: "'integration.invalidation.__.native.server'"
+            millargs: "'integration.invalidation.__.native.daemon'"
             install-sbt: false
 
           - java-version: 17
-            millargs: "'integration.bootstrap[no-java-bootstrap].native.server'"
+            millargs: "'integration.bootstrap[no-java-bootstrap].native.daemon'"
 
     uses: ./.github/workflows/post-build-selective.yml
     with:

changelog.adoc

@@ -150,7 +150,7 @@ to Coursier rather than implementing it in Mill {link-pr}/4145[#4145]
 
 * Honor the `NO_COLOR` env variable {link-pr}/4246[#4246]
 
-* Fix race condition that occasionally caused Mill's background server to exit and
+* Fix race condition that occasionally caused Mill's background daemon to exit and
 restart unnecessarily {link-pr}/4254[#4254]
 
 * Improvements to Mill's https://mill-build.org/mill/android/java.html[experimental

ci/test-mill-bootstrap.sh

@@ -24,4 +24,4 @@ rm -rf out
 
 # Run tests
 ./mill-assembly.jar -i "__.compile"
-./mill-assembly.jar -i "example.scalalib.basic[1-simple].packaged.server.testForked"
+./mill-assembly.jar -i "example.scalalib.basic[1-simple].packaged.daemon.testForked"

core/constants/src/mill/constants/ServerFiles.java renamed to core/constants/src/mill/constants/DaemonFiles.java

@@ -1,34 +1,34 @@
 package mill.constants;
 
 /**
- * Central place containing all the files that live inside the `out/mill-server-*` folder
+ * Central place containing all the files that live inside the `out/mill-daemon-*` folder
  * and documentation about what they do
  */
-public class ServerFiles {
+public class DaemonFiles {
   public static final String processId = "processId";
   public static final String sandbox = "sandbox";
 
   /**
-   * Ensures only a single client is manipulating each mill-server folder at
+   * Ensures only a single launcher is manipulating each mill-daemon folder at
    * a time, either spawning the server or submitting a command. Also used by
    * the server to detect when a client disconnects, so it can terminate execution
    */
-  public static final String clientLock = "clientLock";
+  public static final String launcherLock = "launcherLock";
 
   /**
-   * Lock file ensuring a single server is running in a particular mill-server
+   * Lock file ensuring a single server is running in a particular mill-daemon
    * folder. If multiple servers are spawned in the same folder, only one takes
    * the lock and the others fail to do so and terminate immediately.
    */
-  public static final String serverLock = "serverLock";
+  public static final String daemonLock = "daemonLock";
 
   /**
    * The port used to connect between server and client
    */
   public static final String socketPort = "socketPort";
 
   /**
-   * The pipe by which the client snd server exchange IO
+   * The pipe by which the launcher snd daemon exchange IO
    *
    * Use uniquely-named pipes based on the fully qualified path of the project folder
    * because on Windows the un-qualified name of the pipe must be globally unique

core/constants/src/mill/constants/EnvVars.java

@@ -17,7 +17,7 @@ public class EnvVars {
   public static final String MILL_TEST_RESOURCE_DIR = "MILL_TEST_RESOURCE_DIR";
 
   /**
-   * How long the Mill background server should run before timing out from inactivity
+   * How long the Mill background daemon should run before timing out from inactivity
    */
   public static final String MILL_SERVER_TIMEOUT_MILLIS = "MILL_SERVER_TIMEOUT_MILLIS";
 

core/constants/src/mill/constants/OutFiles.java

@@ -50,12 +50,12 @@ public class OutFiles {
    * Subfolder of `out/` that contains the machinery necessary for a single Mill background
    * server: metadata files, pipes, logs, etc.
    */
-  public static final String millServer = "mill-server";
+  public static final String millDaemon = "mill-daemon";
 
   /**
    * Subfolder of `out/` used to contain the Mill subprocess when run in no-server mode
    */
-  public static final String millNoServer = "mill-no-server";
+  public static final String millNoDaemon = "mill-no-deamon";
 
   /**
    * Lock file used for exclusive access to the Mill output directory

developer.adoc

@@ -27,8 +27,8 @@ The following table contains the main ways you can test the code in
 |===
 | Config | Automated Testing | Manual Testing | Manual Testing CI
 | In-Process Tests | `main.__.test`, `scalalib.test`, `contrib.buildinfo.test`, etc. |  |
-| Sub-Process w/o packaging/publishing| `example.\\__.local.server`, `integration.__.local.server` | `dist.run` | `test-mill-dev.sh`
-| Sub-Process w/ packaging/publishing | `example.\\__.packaged.server`, `integration.__.packaged.server` | `dist.assembly` | `test-mill-release.sh`
+| Sub-Process w/o packaging/publishing| `example.\\__.local.daemon`, `integration.__.local.daemon` | `dist.run` | `test-mill-dev.sh`
+| Sub-Process w/ packaging/publishing | `example.\\__.packaged.daemon`, `integration.__.packaged.daemon` | `dist.assembly` | `test-mill-release.sh`
 | Bootstrapping: Building Mill with your current checkout of Mill |  | `dist.installLocal` | `test-mill-bootstrap.sh`
 |===
 
@@ -60,7 +60,7 @@ and do not exercise the Mill script-file bootstrapping, transformation, and comp
 
 === Sub-Process Tests *without* Packaging/Publishing
 
-`example.\\__.local.server` and `integration.__.local.server` tests run Mill end-to-end in a subprocess,
+`example.\\__.local.daemon` and `integration.__.local.daemon` tests run Mill end-to-end in a subprocess,
 but *without* the expensive/slow steps of packaging the core packages into an assembly jar
 and publishing the remaining packages to
 `~/.ivy2/local`.
@@ -95,7 +95,7 @@ You can reproduce any of the tests manually using `dist.run`, e.g.
 
 [source,console]
 ----
-> ./mill "example.javalib.basic[1-simple].local.server"
+> ./mill "example.javalib.basic[1-simple].local.daemon"
 ----
 
 **Manual Test**
@@ -114,8 +114,8 @@ You can reproduce any of the tests manually using `dist.run`, e.g.
 
 === Sub-Process Tests *with* Packaging/Publishing
 
-`example.\\__.server`, `integration.__.server`, `example.\\__.fork` and
-`integration.__.fork` cover the same test cases as the `.local.server` tests described above, but
+`example.\\__.daemon`, `integration.__.daemon`, `example.\\__.nodaemon` and
+`integration.__.nodaemon` cover the same test cases as the `.local.daemon` tests described above, but
 they perform packaging of the Mill core modules into an assembly jar, and publish the
 remaining modules to `~/.ivy2/local`.
 This results in a more realistic test environment, but at the cost of taking tens-of-seconds
@@ -131,7 +131,7 @@ You can reproduce these tests manually using `dist.installLocal`:
 You can also use `dist.native.installLocal` for a Graal Native Image executable,
 which is slower to create but faster to start than the default executable assembly.
 
-There are two six of these tests, `.{local,assembly,native}.{server,fork}`.
+There are two six of these tests, `.{local,assembly,native}.{daemon,fork}`.
 
 The first label specifies how the Mill code is packaged before testing
 
@@ -148,13 +148,13 @@ This is the slowest mode is only really necessary for debugging Mill's Graal nat
 The second label specifies how the Mill process is managed during the test:
 
 
-1. `.server` test run the test cases with the default configuration, so consecutive commands
-run in the same long-lived background server process
+1. `.daemon` test run the test cases with the default configuration, so consecutive commands
+run in the same long-lived background daemon process
 
-2. `.fork` test run the test cases with `--no-server`, meaning each command runs in a newly
+2. `.nodaemon` test run the test cases with `--no-daemon`, meaning each command runs in a newly
 spawned Mill process
 
-In general you should spend most of your time working with the `.local.server` version of the
+In general you should spend most of your time working with the `.local.daemon` version of the
 `example` and `integration` tests to save time, and only run the others if you have a specific
 thing you want to test that needs those code paths to run.
 

dist/scripts/src/mill.bat

@@ -272,11 +272,15 @@ if [%~1%]==[--bsp] (
       if [%~1%]==[--no-server] (
         set MILL_FIRST_ARG=%1%
       ) else (
-        if [%~1%]==[--repl] (
+        if [%~1%]==[--no-daemon] (
           set MILL_FIRST_ARG=%1%
         ) else (
-          if [%~1%]==[--help] (
+          if [%~1%]==[--repl] (
             set MILL_FIRST_ARG=%1%
+          ) else (
+            if [%~1%]==[--help] (
+              set MILL_FIRST_ARG=%1%
+            )
           )
         )
       )

dist/scripts/src/mill.sh

@@ -309,7 +309,7 @@ if [ -z "$MILL_MAIN_CLI" ] ; then
 fi
 
 MILL_FIRST_ARG=""
-if [ "$1" = "--bsp" ] || [ "$1" = "-i" ] || [ "$1" = "--interactive" ] || [ "$1" = "--no-server" ] || [ "$1" = "--repl" ] || [ "$1" = "--help" ] ; then
+if [ "$1" = "--bsp" ] || [ "$1" = "-i" ] || [ "$1" = "--interactive" ] || [ "$1" = "--no-server" ] || [ "$1" = "--no-daemon" ] || [ "$1" = "--repl" ] || [ "$1" = "--help" ] ; then
   # Need to preserve the first position of those listed options
   MILL_FIRST_ARG=$1
   shift

example/depth/sandbox/1-task/build.mill

@@ -78,14 +78,14 @@ def osProcTask = Task {
 //
 // Lastly, there is the possibily of calling `os.pwd` outside of a task. When outside of
 // a task there is no `.dest/` folder associated, so instead Mill will redirect `os.pwd`
-// towards an empty `sandbox/` folder in `out/mill-server/...`:
+// towards an empty `sandbox/` folder in `out/mill-daemon/...`:
 
 val externalPwd = os.pwd
 def externalPwdTask = Task { println(externalPwd.toString) }
 
 /** Usage
 > ./mill externalPwdTask
-.../out/mill-server/sandbox
+.../out/mill-daemon/sandbox
 */
 
 // === Limitations of Mill's Sandboxing