1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
|
<html><head><meta charset="utf-8" /><link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css" rel="stylesheet" type="text/css" /><link href="https://maxcdn.bootstrapcdn.com/font-awesome/4.5.0/css/font-awesome.min.css" rel="stylesheet" type="text/css" /><link href="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/9.1.0/styles/github-gist.min.css" rel="stylesheet" type="text/css" /><title>Intro to Mill</title><style>@media (min-width: 60em) {.WideStyles-header{
bottom: 0px;
display: flex;
flex-direction: column;
justify-content: center;
position: fixed;
top: 0px;
width: 25%;
}
.WideStyles-tableOfContentsItem{
display: inline-block;
overflow: hidden;
text-overflow: ellipsis;
vertical-align: middle;
width: 100%;
}
.WideStyles-tableOfContents{
display: flex;
flex-direction: column;
flex-grow: 1;
flex-shrink: 1;
min-height: 0px;
width: 100%;
}
.WideStyles-content{
box-sizing: border-box;
margin-left: 25%;
padding: 48px;
}
.WideStyles-footer{
bottom: 0px;
height: 50px;
position: fixed;
width: 25%;
}
.WideStyles-marginLeftZero{
margin-left: 0px;
}
}</style><style>@media (max-width: 60em) {.NarrowStyles-header{
margin-bottom: 10px;
}
.NarrowStyles-content{
padding: 16px;
}
.NarrowStyles-headerContent{
align-items: center;
display: flex;
flex-direction: row;
width: 100%;
}
.NarrowStyles-flexFont{
font-size: 4vw;
}
.NarrowStyles-disappear{
display: none;
}
.NarrowStyles-floatLeft{
float: left;
margin-left: 30px;
}
}</style><style>.Styles-hoverBox{
align-items: center;
display: flex;
flex-direction: row;
justify-content: space-between;
}
.Styles-hoverBox:hover .Styles-hoverLink{
opacity: 0.5;
}
.Styles-hoverLink{
opacity: 0.1;
}
.Styles-hoverLink:hover{
opacity: 1.0;
}
.Styles-headerStyle{
background-color: rgb(61, 79, 93);
box-sizing: border-box;
display: flex;
}
.Styles-headerLinkBox{
display: flex;
flex: 1;
flex-direction: column;
}
.Styles-headerLink{
align-items: center;
display: flex;
flex: 1;
justify-content: center;
padding: 10px 10px;
}
.Styles-footerStyle{
color: rgb(158, 167, 174);
display: flex;
justify-content: center;
}
.Styles-subtleLink{
text-decoration: none;
}
</style><script src="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/9.1.0/highlight.min.js"></script><script src="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/9.1.0/languages/scala.min.js"></script><script>hljs.initHighlightingOnLoad();</script><meta name="viewport" content="initial-scale = 1.0,maximum-scale = 1.0" /></head><body style="margin: 0px;background-color: #f8f8f8;"><div class=" WideStyles-header NarrowStyles-header Styles-headerStyle"><div class=" NarrowStyles-headerContent"><h1 style="text-align: center;padding: 30px 30px;margin: 0px;"><a style="color: #f8f8f8;font-weight: bold;" href="" class=" Styles-subtleLink NarrowStyles-flexFont"><img src="logo-white.svg" style="height: 30px;margin-top: -5px;" /> Mill</a></h1><div class=" Styles-headerLinkBox"><div class=" WideStyles-tableOfContents" style="color: #f8f8f8;"><div style="padding-left: 40px;" class=" NarrowStyles-disappear"><b>Pages</b></div><div style="overflow-y: auto;flex-shrink: 1;min-height: 0px;"><ul style="overflow: hidden;text-align: start;margin-top: 10px;white-space: nowrap;text-overflow: ellipsis;margin-right: 10px;"><li class=" WideStyles-marginLeftZero NarrowStyles-floatLeft"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="index.html">Intro to Mill</a></li><li class=" WideStyles-marginLeftZero NarrowStyles-floatLeft"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="page/configuring-mill.html">Configuring Mill</a></li><li class=" WideStyles-marginLeftZero NarrowStyles-floatLeft"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="page/common-project-layouts.html">Common Project Layouts</a></li><li class=" WideStyles-marginLeftZero NarrowStyles-floatLeft"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="page/tasks.html">Tasks</a></li><li class=" WideStyles-marginLeftZero NarrowStyles-floatLeft"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="page/modules.html">Modules</a></li><li class=" WideStyles-marginLeftZero NarrowStyles-floatLeft"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="page/cross-builds.html">Cross Builds</a></li><li class=" WideStyles-marginLeftZero NarrowStyles-floatLeft"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="page/extending-mill.html">Extending Mill</a></li><li class=" WideStyles-marginLeftZero NarrowStyles-floatLeft"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="page/mill-internals.html">Mill Internals</a></li><li class=" WideStyles-marginLeftZero NarrowStyles-floatLeft"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="page/contrib-modules.html">Contrib Modules</a></li><li class=" WideStyles-marginLeftZero NarrowStyles-floatLeft"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="page/thirdparty-modules.html">Thirdparty Modules</a></li></ul></div></div></div></div><hr class=" NarrowStyles-disappear" style="background-color: #f8f8f8;width: 80%;" /><div class=" WideStyles-tableOfContents NarrowStyles-disappear" style="color: #f8f8f8;"><div style="padding-left: 40px;" class=" NarrowStyles-disappear"><b>Table of Contents</b></div><div style="overflow-y: auto;flex-shrink: 1;min-height: 0px;"><ul style="overflow: hidden;text-align: start;margin-top: 10px;white-space: nowrap;text-overflow: ellipsis;margin-right: 10px;"><li style="margin-left: 0px;"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="#installation">Installation</a></li><li style="margin-left: 20px;"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="#os-x">OS X</a></li><li style="margin-left: 20px;"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="#arch-linux">Arch Linux</a></li><li style="margin-left: 20px;"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="#freebsd">FreeBSD</a></li><li style="margin-left: 20px;"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="#windows">Windows</a></li><li style="margin-left: 20px;"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="#docker">Docker</a></li><li style="margin-left: 20px;"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="#manual">Manual</a></li><li style="margin-left: 20px;"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="#bootstrap-scripts-linuxos-x-only">Bootstrap Scripts (Linux/OS-X Only)</a></li><li style="margin-left: 0px;"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="#getting-started">Getting Started</a></li><li style="margin-left: 0px;"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="#output">Output</a></li><li style="margin-left: 0px;"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="#multiple-modules">Multiple Modules</a></li><li style="margin-left: 20px;"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="#java-example">Java Example</a></li><li style="margin-left: 20px;"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="#scala-example">Scala Example</a></li><li style="margin-left: 0px;"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="#watch-and-re-evaluate">Watch and Re-evaluate</a></li><li style="margin-left: 0px;"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="#command-line-tools">Command-line Tools</a></li><li style="margin-left: 20px;"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="#all">all</a></li><li style="margin-left: 20px;"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="#resolve">resolve</a></li><li style="margin-left: 20px;"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="#inspect">inspect</a></li><li style="margin-left: 20px;"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="#show">show</a></li><li style="margin-left: 20px;"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="#path">path</a></li><li style="margin-left: 20px;"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="#plan">plan</a></li><li style="margin-left: 20px;"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="#visualize">visualize</a></li><li style="margin-left: 20px;"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="#visualizeplan">visualizePlan</a></li><li style="margin-left: 20px;"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="#clean">clean</a></li><li style="margin-left: 20px;"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="#search-for-dependency-updates">Search for dependency updates</a></li><li style="margin-left: 0px;"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="#intellij-support">IntelliJ Support</a></li><li style="margin-left: 0px;"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="#the-build-repl">The Build Repl</a></li><li style="margin-left: 0px;"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="#deploying-your-code">Deploying your code</a></li><li style="margin-left: 0px;"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="#structure-of-the-out-folder">Structure of the out/ folder</a></li><li style="margin-left: 0px;"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="#overriding-mill-versions">Overriding Mill Versions</a></li><li style="margin-left: 20px;"><a style="color: #f8f8f8;" class=" WideStyles-tableOfContentsItem" href="#development-releases">Development Releases</a></li></ul></div></div></div><div class=" WideStyles-content NarrowStyles-content" style="max-width: 900px;"><h1>Intro to Mill</h1><div style="margin-bottom: 10px;"><div style="display: flex;flex-direction: row;justify-content: space-between;"><div></div><a href="page/configuring-mill.html">Configuring Mill <i class="fa fa-arrow-right" aria-hidden="true"></i></a></div></div><p><a href="https://github.com/lihaoyi/mill">Mill</a> is your shiny new Java/Scala build tool! <a href="http://www.lihaoyi.com/post/SowhatswrongwithSBT.html">Scared of SBT</a>? Melancholy over Maven? Grumbling about Gradle? Baffled by Bazel? Give Mill a try!</p>
<p>Mill aims for simplicity by re-using concepts you are already <a href="http://www.lihaoyi.com/post/BuildToolsasPureFunctionalPrograms.html">familiar with</a>, borrowing ideas from modern tools like <a href="https://bazel.build/">Bazel</a>, to let you build your projects in a way that's simple, fast, and predictable.</p>
<p>Mill has built in support for the <a href="https://www.scala-lang.org/">Scala</a> programming language, and can serve as a replacement for <a href="http://www.scala-sbt.org/">SBT</a>, but can also be <a href="http://www.lihaoyi.com/mill/page/extending-mill.html">extended</a> to support any other language or platform via modules (written in Java or Scala) or through external subprocesses.</p><h2 id="installation" class="Styles-hoverBox">Installation<a href="#installation" class=" Styles-hoverLink"><i class="fa fa-link" aria-hidden="true"></i></a></h2><h3 id="os-x" class="Styles-hoverBox">OS X<a href="#os-x" class=" Styles-hoverLink"><i class="fa fa-link" aria-hidden="true"></i></a></h3>
<p>Installation via <a href="https://github.com/Homebrew/homebrew-core/blob/master/Formula/mill.rb">homebrew</a>:</p>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="sh">brew install mill
</code></pre><h3 id="arch-linux" class="Styles-hoverBox">Arch Linux<a href="#arch-linux" class=" Styles-hoverLink"><i class="fa fa-link" aria-hidden="true"></i></a></h3>
<p>Arch Linux has an <a href="https://aur.archlinux.org/packages/mill/">AUR package for mill</a>:</p>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="bash">pacaur -S mill
</code></pre><h3 id="freebsd" class="Styles-hoverBox">FreeBSD<a href="#freebsd" class=" Styles-hoverLink"><i class="fa fa-link" aria-hidden="true"></i></a></h3>
<p>Installation via <a href="http://man.freebsd.org/pkg/8">pkg(8)</a>:</p>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="sh">pkg install mill
</code></pre><h3 id="windows" class="Styles-hoverBox">Windows<a href="#windows" class=" Styles-hoverLink"><i class="fa fa-link" aria-hidden="true"></i></a></h3>
<p>To get started, download Mill from: <a href="https://github.com/lihaoyi/mill/releases/download/0.5.1/0.5.1-assembly">https://github.com/lihaoyi/mill/releases/download/0.5.1/0.5.1-assembly</a>, and save it as <code>mill.bat</code>.</p>
<p>If you're using <a href="https://scoop.sh">Scoop</a> you can install Mill via</p>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="bash">scoop install mill
</code></pre>
<p>Mill also works on a sh environment on Windows (e.g., <a href="https://www.msys2.org">MSYS2</a>, <a href="https://www.cygwin.com">Cygwin</a>, <a href="https://gitforwindows.org">Git-Bash</a>, <a href="https://docs.microsoft.com/en-us/windows/wsl">WSL</a>; to get started, follow the instructions in the <a href="#manual">manual</a> section below. Note that:</p>
<ul>
<li>
<p>In some environments (such as WSL), mill might have to be run using interactive mode (<code>-i</code>)</p></li>
<li>
<p>On Cygwin, run the following after downloading mill:</p></li>
</ul>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="bash">sed -i '0,/-cp "\$0"/{s/-cp "\$0"/-cp `cygpath -w "\$0"`/}; 0,/-cp "\$0"/{s/-cp "\$0"/-cp `cygpath -w "\$0"`/}' /usr/local/bin/mill
</code></pre><h3 id="docker" class="Styles-hoverBox">Docker<a href="#docker" class=" Styles-hoverLink"><i class="fa fa-link" aria-hidden="true"></i></a></h3>
<p>You can download and run a <a href="https://hub.docker.com/r/nightscape/scala-mill/">Docker image containing OpenJDK, Scala and Mill</a> using</p>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="bash">docker pull nightscape/scala-mill
docker run -it nightscape/scala-mill
</code></pre><h3 id="manual" class="Styles-hoverBox">Manual<a href="#manual" class=" Styles-hoverLink"><i class="fa fa-link" aria-hidden="true"></i></a></h3>
<p>To get started, download Mill and install it into your system via the following <code>curl</code>/<code>chmod</code> command:</p>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="bash">sudo curl -L https://github.com/lihaoyi/mill/releases/download/0.5.1/0.5.1 > /usr/local/bin/mill && sudo chmod +x /usr/local/bin/mill
</code></pre><h3 id="bootstrap-scripts-linuxos-x-only" class="Styles-hoverBox">Bootstrap Scripts (Linux/OS-X Only)<a href="#bootstrap-scripts-linuxos-x-only" class=" Styles-hoverLink"><i class="fa fa-link" aria-hidden="true"></i></a></h3>
<p>If you are using Mill in a codebase, you can commit the bootstrap launcher as a <code>./mill</code> script in the project folder:</p>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="bash">curl -L https://github.com/lihaoyi/mill/releases/download/0.5.1/0.5.1 > mill && chmod +x mill
</code></pre>
<p>Now, anyone who wants to work with the project can simply use the <code>./mill</code> script directly:</p>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="bash">./mill version
./mill __.compile
</code></pre>
<p>The <code>mill</code> command will automatically use the version specified by the bootstrap script, even if you installed it via other means. The <code>./mill</code> file has a version number embedded within it, which you can update simply by editing the script. Note this only works for versions 0.5.0 and above.</p>
<p>Bootstrap scripts are also useful for running Mill in CI, ensuring that your Jenkins/Travis/etc. box has the correct version of Mill present to build/compile/test your code.</p><h2 id="getting-started" class="Styles-hoverBox">Getting Started<a href="#getting-started" class=" Styles-hoverLink"><i class="fa fa-link" aria-hidden="true"></i></a></h2>
<p>The simplest Mill build for a Java project looks as follows:</p>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="scala">// build.sc
import mill._, scalalib._
object foo extends JavaModule {
}
</code></pre>
<p>The simplest Mill build for a Scala project looks as follows:</p>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="scala">// build.sc
import mill._, scalalib._
object foo extends ScalaModule {
def scalaVersion = "2.12.4"
}
</code></pre>
<p>Both of these would build a project laid out as follows:</p>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="">build.sc
foo/
src/
FileA.java
FileB.scala
resources/
...
out/
foo/
...
</code></pre>
<p>You can download an example project with this layout here:</p>
<ul>
<li><a href="example-1.zip">Example 1</a></li>
</ul>
<p>The source code for this module would live in the <code>foo/src/</code> folder, matching the name you assigned to the module. Output for this module (compiled files, resolved dependency lists, ...) would live in <code>out/foo/</code>.</p>
<p>This can be run from the Bash shell via:</p>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="bash">$ mill foo.compile # compile sources into classfiles
$ mill foo.run # run the main method, if any
$ mill foo.runBackground # run the main method in the background
$ mill foo.launcher # prepares a foo/launcher/dest/run you can run later
$ mill foo.jar # bundle the classfiles into a jar
$ mill foo.assembly # bundle classfiles and all dependencies into a jar
$ mill -i foo.console # start a Scala console within your project (in interactive mode: "-i")
$ mill -i foo.repl # start an Ammonite REPL within your project (in interactive mode: "-i")
</code></pre>
<p>You can run <code>mill resolve __</code> to see a full list of the different tasks that are available, <code>mill resolve foo._</code> to see the tasks within <code>foo</code>, <code>mill inspect
foo.compile</code> to inspect a task's doc-comment documentation or what it depends on, or <code>mill show foo.scalaVersion</code> to show the output of any task.</p>
<p>The most common <strong>tasks</strong> that Mill can run are cached <strong>targets</strong>, such as <code>compile</code>, and un-cached <strong>commands</strong> such as <code>foo.run</code>. Targets do not re-evaluate unless one of their inputs changes, where-as commands re-run every time.</p><h2 id="output" class="Styles-hoverBox">Output<a href="#output" class=" Styles-hoverLink"><i class="fa fa-link" aria-hidden="true"></i></a></h2>
<p>Mill puts all its output in the top-level <code>out/</code> folder. The above commands would end up in:</p>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="text">out/
foo/
compile/
run/
jar/
assembly/
</code></pre>
<p>Within the output folder for each task, there's a <code>meta.json</code> file containing the metadata returned by that task, and a <code>dest/</code> folder containing any files that the task generates. For example, <code>out/foo/compile/dest/</code> contains the compiled classfiles, while <code>out/foo/assembly/dest/</code> contains the self-contained assembly with the project's classfiles jar-ed up with all its dependencies.</p>
<p>Given a task <code>foo.bar</code>, all its output and results can be found be within its respective <code>out/foo/bar/</code> folder.</p><h2 id="multiple-modules" class="Styles-hoverBox">Multiple Modules<a href="#multiple-modules" class=" Styles-hoverLink"><i class="fa fa-link" aria-hidden="true"></i></a></h2><h3 id="java-example" class="Styles-hoverBox">Java Example<a href="#java-example" class=" Styles-hoverLink"><i class="fa fa-link" aria-hidden="true"></i></a></h3>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="scala">// build.sc
import mill._, scalalib._
object foo extends JavaModule
object bar extends JavaModule {
def moduleDeps = Seq(foo)
}
</code></pre><h3 id="scala-example" class="Styles-hoverBox">Scala Example<a href="#scala-example" class=" Styles-hoverLink"><i class="fa fa-link" aria-hidden="true"></i></a></h3>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="scala">// build.sc
import mill._, scalalib._
object foo extends ScalaModule {
def scalaVersion = "2.12.4"
}
object bar extends ScalaModule {
def moduleDeps = Seq(foo)
def scalaVersion = "2.12.4"
}
</code></pre>
<p>You can define multiple modules the same way you define a single module, using <code>def moduleDeps</code> to define the relationship between them. The above builds expects the following project layout:</p>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="">build.sc
foo/
src/
Main.scala
resources/
...
bar/
src/
Main2.scala
resources/
...
out/
foo/
...
bar/
...
</code></pre>
<p>And can be built/run using:</p>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="bash">$ mill foo.compile
$ mill bar.compile
$ mill foo.run
$ mill bar.run
$ mill foo.jar
$ mill bar.jar
$ mill foo.assembly
$ mill bar.assembly
</code></pre>
<p>Mill's evaluator will ensure that the modules are compiled in the right order, and re-compiled as necessary when source code in each module changes.</p>
<p>Modules can also be nested:</p>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="scala">// build.sc
import mill._, scalalib._
object foo extends ScalaModule {
def scalaVersion = "2.12.4"
object bar extends ScalaModule {
def moduleDeps = Seq(foo)
def scalaVersion = "2.12.4"
}
}
</code></pre>
<p>Which would result in a similarly nested project layout:</p>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="">build.sc
foo/
src/
Main.scala
resources/
...
bar/
src/
Main2.scala
resources/
...
out/
foo/
...
bar/
...
</code></pre>
<p>Where the nested modules can be run via:</p>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="bash">$ mill foo.compile
$ mill foo.bar.compile
$ mill foo.run
$ mill foo.bar.run
$ mill foo.jar
$ mill foo.bar.jar
$ mill foo.assembly
$ mill foo.bar.assembly
</code></pre><h2 id="watch-and-re-evaluate" class="Styles-hoverBox">Watch and Re-evaluate<a href="#watch-and-re-evaluate" class=" Styles-hoverLink"><i class="fa fa-link" aria-hidden="true"></i></a></h2>
<p>You can use the <code>--watch</code> flag to make Mill watch a task's inputs, re-evaluating the task as necessary when the inputs change:</p>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="bash">$ mill --watch foo.compile
$ mill --watch foo.run
$ mill -w foo.compile
$ mill -w foo.run
</code></pre>
<p>Mill's <code>--watch</code> flag watches both the files you are building using Mill, as well as Mill's own <code>build.sc</code> file and anything it imports, so any changes to your <code>build.sc</code> will automatically get picked up.</p>
<p>For long-running processes like web-servers, you can use <code>.runBackground</code> to make sure they re-compile and re-start when code changes, forcefully terminating the previous process even though it may be still alive:</p>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="bash">$ mill -w foo.compile
$ mill -w foo.runBackground
</code></pre><h2 id="command-line-tools" class="Styles-hoverBox">Command-line Tools<a href="#command-line-tools" class=" Styles-hoverLink"><i class="fa fa-link" aria-hidden="true"></i></a></h2>
<p>Mill comes built in with a small number of useful command-line utilities:</p><h3 id="all" class="Styles-hoverBox">all<a href="#all" class=" Styles-hoverLink"><i class="fa fa-link" aria-hidden="true"></i></a></h3>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="bash">mill all foo.{compile,run}
mill all "foo.{compile,run}"
mill all foo.compile foo.run
mill all _.compile # run compile for every top-level module
mill all __.compile # run compile for every module
</code></pre>
<p><code>all</code> runs multiple tasks in a single command</p><h3 id="resolve" class="Styles-hoverBox">resolve<a href="#resolve" class=" Styles-hoverLink"><i class="fa fa-link" aria-hidden="true"></i></a></h3>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="bash">$ mill resolve _
main
moduledefs
core
scalaworker
scalalib
scalajslib
integration
testRepos
...
$ mill resolve _.compile
main.compile
moduledefs.compile
core.compile
scalalib.worker.compile
scalalib.compile
scalajslib.compile
integration.compile
$ mill resolve core._
core.test
core.compile
core.publishVersion
core.runClasspath
core.testArgs
core.sources
...
</code></pre>
<p><code>resolve</code> lists the tasks that match a particular query, without running them. This is useful for "dry running" an <code>mill all</code> command to see what would be run before you run them, or to explore what modules or tasks are available from the command line using <code>resolve _</code>, <code>resolve foo._</code>, etc.</p>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="bash">mill resolve foo.{compile,run}
mill resolve "foo.{compile,run}"
mill resolve foo.compile foo.run
mill resolve _.compile # list the compile tasks for every top-level module
mill resolve __.compile # list the compile tasks for every module
mill resolve _ # list every top level module or task
mill resolve foo._ # list every task directly within the foo module
mill resolve __ # list every module or task recursively
mill resolve foo.__ # list every task recursively within the foo module
</code></pre><h3 id="inspect" class="Styles-hoverBox">inspect<a href="#inspect" class=" Styles-hoverLink"><i class="fa fa-link" aria-hidden="true"></i></a></h3>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="bash">$ mill inspect core.run
core.run(ScalaModule.scala:211)
Inputs:
core.mainClass
core.runClasspath
core.forkArgs
core.forkEnv
</code></pre>
<p><code>inspect</code> is a more verbose version of <a href="#resolve">resolve</a>. In addition to printing out the name of one-or-more tasks, it also displays its source location and a list of input tasks. This is very useful for debugging and interactively exploring the structure of your build from the command line.</p>
<p><code>inspect</code> also works with the same <code>_</code>/<code>__</code> wildcard/query syntaxes that <a href="#all">all</a>/<a href="#resolve">resolve</a> do:</p>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="bash">mill inspect foo.compile
mill inspect foo.{compile,run}
mill inspect "foo.{compile,run}"
mill inspect foo.compile foo.run
mill inspect _.compile
mill inspect __.compile
mill inspect _
mill inspect foo._
mill inspect __
mill inspect foo._
</code></pre><h3 id="show" class="Styles-hoverBox">show<a href="#show" class=" Styles-hoverLink"><i class="fa fa-link" aria-hidden="true"></i></a></h3>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="bash">$ mill show core.scalaVersion
"2.12.4"
</code></pre>
<p>By default, Mill does not print out the metadata from evaluating a task. Most people would not be interested in e.g. viewing the metadata related to incremental compilation: they just want to compile their code! However, if you want to inspect the build to debug problems, you can make Mill show you the metadata output for a task using the <code>show</code> command:</p>
<p>All tasks return values that can be <code>show</code>n, not just configuration values. e.g. <code>compile</code> returns that path to the <code>classes</code> and <code>analysisFile</code> that are produced by the compilation:</p>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="bash">$ mill show foo.compile
{
"analysisFile": "/Users/lihaoyi/Dropbox/Github/test/out/foo/compile/dest/zinc",
"classes": {
"path": "/Users/lihaoyi/Dropbox/Github/test/out/foo/compile/dest/classes"
}
}
</code></pre>
<p><code>show</code> is generally useful as a debugging tool, to see what is going on in your build:</p>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="bash">$ mill show foo.sources
[
"/Users/lihaoyi/Dropbox/Github/test/foo/src"
]
$ mill show foo.compileDepClasspath
[
".../org/scala-lang/scala-compiler/2.12.4/scala-compiler-2.12.4.jar",
".../org/scala-lang/scala-library/2.12.4/scala-library-2.12.4.jar",
".../org/scala-lang/scala-reflect/2.12.4/scala-reflect-2.12.4.jar",
".../org/scala-lang/modules/scala-xml_2.12/1.0.6/scala-xml_2.12-1.0.6.jar"
]
</code></pre>
<p><code>show</code> is also useful for interacting with Mill from external tools, since the JSON it outputs is structured and easily parsed & manipulated.</p><h3 id="path" class="Styles-hoverBox">path<a href="#path" class=" Styles-hoverLink"><i class="fa fa-link" aria-hidden="true"></i></a></h3>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="bash">$ mill path core.assembly core.sources
core.sources
core.allSources
core.allSourceFiles
core.compile
core.localClasspath
core.assembly
</code></pre>
<p><code>mill path</code> prints out a dependency chain between the first task and the second. It is very useful for exploring the build graph and trying to figure out how data gets from one task to another. If there are multiple possible dependency chains, one of them is picked arbitrarily.</p><h3 id="plan" class="Styles-hoverBox">plan<a href="#plan" class=" Styles-hoverLink"><i class="fa fa-link" aria-hidden="true"></i></a></h3>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="bash">$ mill plan moduledefs.compileClasspath
moduledefs.transitiveLocalClasspath
moduledefs.resources
moduledefs.unmanagedClasspath
moduledefs.scalaVersion
moduledefs.platformSuffix
moduledefs.compileIvyDeps
moduledefs.scalaLibraryIvyDeps
moduledefs.ivyDeps
moduledefs.transitiveIvyDeps
moduledefs.compileClasspath
</code></pre>
<p><code>mill plan foo</code> prints out what tasks would be evaluated, in what order, if you ran <code>mill foo</code>, but without actually running them. This is a useful tool for debugging your build: e.g. if you suspect a task <code>foo</code> is running things that it shouldn't be running, a quick <code>mill plan</code> will list out all the upstream tasks that <code>foo</code> needs to run, and you can then follow up with <code>mill path</code> on any individual upstream task to see exactly how <code>foo</code> depends on it.</p><h3 id="visualize" class="Styles-hoverBox">visualize<a href="#visualize" class=" Styles-hoverLink"><i class="fa fa-link" aria-hidden="true"></i></a></h3>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="bash">$ mill show visualize core._
[
".../out/visualize/dest/out.txt",
".../out/visualize/dest/out.dot",
".../out/visualize/dest/out.json",
".../out/visualize/dest/out.png",
".../out/visualize/dest/out.svg"
]
</code></pre>
<p><code>mill show visualize</code> takes a subset of the Mill build graph (e.g. <code>core._</code> is every task directly under the <code>core</code> module) and draws out their relationships in <code>.svg</code> and <code>.png</code> form for you to inspect. It also generates <code>.txt</code>, <code>.dot</code> and <code>.json</code> for easy processing by downstream tools.</p>
<p>The above command generates the following diagram:</p>
<p><div style="text-align: center"><img src="VisualizeCore.svg" alt="VisualizeCore.svg" style="max-width: 100%; max-height: 500px" /></div></p>
<p>Another use case is to view the relationships between modules:</p>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="bash">$ mill show visualize __.compile
</code></pre>
<p>This command diagrams the relationships between the <code>compile</code> tasks of each module, which illustrates which module depends on which other module's compilation output:</p>
<p><div style="text-align: center"><img src="VisualizeCompile.svg" alt="VisualizeCompile.svg" style="max-width: 100%; max-height: 500px" /></div></p><h3 id="visualizeplan" class="Styles-hoverBox">visualizePlan<a href="#visualizeplan" class=" Styles-hoverLink"><i class="fa fa-link" aria-hidden="true"></i></a></h3>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="bash">$ mill show visualizePlan moduledefs.compile
[
".../out/visualizePlan/dest/out.txt",
".../out/visualizePlan/dest/out.dot",
".../out/visualizePlan/dest/out.json",
".../out/visualizePlan/dest/out.png",
".../out/visualizePlan/dest/out.svg"
]
</code></pre>
<p><code>mill show visualizePlan</code> is similar to <code>mill show visualize</code> except that it shows a graph of the entire build plan, including tasks not directly resolved by the query. Tasks directly resolved are shown with a solid border, and dependencies are shown with a dotted border.</p>
<p>The above command generates the following diagram:</p>
<p><div style="text-align: center"><img src="VisualizePlan.svg" alt="VisualizePlan.svg" style="max-width: 100%; max-height: 500px" /></div></p><h3 id="clean" class="Styles-hoverBox">clean<a href="#clean" class=" Styles-hoverLink"><i class="fa fa-link" aria-hidden="true"></i></a></h3>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="bash">$ mill clean
</code></pre>
<p><code>clean</code> deletes all the cached outputs of previously executed tasks. It can apply to the entire project, entire modules, or specific tasks.</p>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="bash">mill clean # clean all outputs
mill clean foo # clean all outputs for module 'foo' (including nested modules)
mill clean foo.compile # only clean outputs for task 'compile' in module 'foo'
mill clean foo.{compile,run}
mill clean "foo.{compile,run}"
mill clean foo.compile foo.run
mill clean _.compile
mill clean __.compile
</code></pre><h3 id="search-for-dependency-updates" class="Styles-hoverBox">Search for dependency updates<a href="#search-for-dependency-updates" class=" Styles-hoverLink"><i class="fa fa-link" aria-hidden="true"></i></a></h3>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="bash">$ mill mill.scalalib.Dependency/updates
</code></pre>
<p>Mill can search for updated versions of your project's dependencies, if available from your project's configured repositories. Note that it uses heuristics based on common versionning schemes, so it may not work as expected for dependencies with particularly weird version numbers.</p>
<p>Current limitations: - Only works for <code>JavaModule</code>s (including <code>ScalaModule</code>s, <code>CrossScalaModule</code>s, etc.) and Maven repositories. - Always applies to all modules in the build. - Doesn't apply to <code>$ivy</code> dependencies used in the build definition itself.</p>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="bash">mill mill.scalalib.Dependency/updates
mill mill.scalalib.Dependency/updates --allowPreRelease true # also show pre-release versions
</code></pre><h2 id="intellij-support" class="Styles-hoverBox">IntelliJ Support<a href="#intellij-support" class=" Styles-hoverLink"><i class="fa fa-link" aria-hidden="true"></i></a></h2>
<p>Mill supports IntelliJ by default. Use <code>mill mill.scalalib.GenIdea/idea</code> to generate an IntelliJ project config for your build.</p>
<p>This also configures IntelliJ to allow easy navigate & code-completion within your build file itself.</p><h2 id="the-build-repl" class="Styles-hoverBox">The Build Repl<a href="#the-build-repl" class=" Styles-hoverLink"><i class="fa fa-link" aria-hidden="true"></i></a></h2>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="bash">$ mill -i
Loading...
@ foo
res1: foo.type = ammonite.predef.build#foo:2
Commands:
.runLocal(args: String*)()
.run(args: String*)()
.runMainLocal(mainClass: String, args: String*)()
.runMain(mainClass: String, args: String*)()
.console()()
Targets:
.allSources()
.artifactId()
.artifactName()
...
@ foo.compile
res3: mill.package.T[mill.scalalib.CompilationResult] = mill.scalalib.ScalaModule#compile:152
Inputs:
foo.scalaVersion
foo.allSources
foo.compileDepClasspath
...
@ foo.compile()
res2: mill.scalalib.CompilationResult = CompilationResult(
root/'Users/'lihaoyi/'Dropbox/'Github/'test/'out/'foo/'compile/'dest/'zinc,
PathRef(root/'Users/'lihaoyi/'Dropbox/'Github/'test/'out/'foo/'compile/'dest/'classes, false)
)
</code></pre>
<p>You can run <code>mill -i</code> to open a build REPL; this is a Scala console with your <code>build.sc</code> loaded, which lets you run tasks interactively. The task-running syntax is slightly different from the command-line, but more in-line with how you would depend on tasks from within your build file.</p>
<p>You can use this REPL to interactively explore your build to see what is available.</p><h2 id="deploying-your-code" class="Styles-hoverBox">Deploying your code<a href="#deploying-your-code" class=" Styles-hoverLink"><i class="fa fa-link" aria-hidden="true"></i></a></h2>
<p>The two most common things to do once your code is complete is to make an assembly (e.g. for deployment/installation) or publishing (e.g. to Maven Central). Mill comes with both capabilities built in.</p>
<p>Mill comes built-in with the ability to make assemblies. Given a simple Mill build:</p>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="scala">// build.sc
import mill._, scalalib._
object foo extends ScalaModule {
def scalaVersion = "2.12.4"
}
</code></pre>
<p>You can make a self-contained assembly via:</p>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="bash">$ mill foo.assembly
$ ls -lh out/foo/assembly/dest/out.jar
-rw-r--r-- 1 lihaoyi staff 5.0M Feb 17 11:14 out/foo/assembly/dest/out.jar
</code></pre>
<p>You can then move the <code>out.jar</code> file anywhere you would like, and run it standalone using <code>java</code>:</p>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="bash">$ java -cp out/foo/assembly/dest/out.jar foo.Example
Hello World!
</code></pre>
<p>To publish to Maven Central, you need to make <code>foo</code> also extend Mill's <code>PublishModule</code> trait:</p>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="scala">// build.sc
import mill._, scalalib._, publish._
object foo extends ScalaModule with PublishModule {
def scalaVersion = "2.12.4"
def publishVersion = "0.0.1"
def pomSettings = PomSettings(
description = "Hello",
organization = "com.lihaoyi",
url = "https://github.com/lihaoyi/example",
licenses = Seq(License.MIT),
versionControl = VersionControl.github("lihaoyi", "example"),
developers = Seq(
Developer("lihaoyi", "Li Haoyi","https://github.com/lihaoyi")
)
)
}
</code></pre>
<p>You can change the name of the published artifact (artifactId in the Maven POM) by overriding <code>artifactName</code> in the module you want to publish.</p>
<p>You can download an example project with this layout here:</p>
<ul>
<li><a href="example-2.zip">Example 2</a></li>
</ul>
<p>Which you can then publish using the <code>mill foo.publish</code> command, which takes your sonatype credentials (e.g. <code>lihaoyi:foobarbaz</code>) and GPG password as inputs:</p>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="bash">$ mill foo.publish
Missing arguments: (--sonatypeCreds: String, --release: Boolean)
Arguments provided did not match expected signature:
publish
--sonatypeCreds String (format: "username:password")
--gpgPassphrase String (default null)
--gpgKeyName String (default null)
--signed Boolean (default true)
--release Boolean
</code></pre>
<p>You also need to specify <code>release</code> as <code>true</code> or <code>false</code>, depending on whether you just want to stage your module on <code>oss.sonatype.org</code> or you want Mill to complete the release process to Maven Central.</p>
<p>If you are publishing multiple artifacts, you can also use <code>mill mill.scalalib.PublishModule/publishAll</code> as described <a href="http://www.lihaoyi.com/mill/page/common-project-layouts.html#publishing">here</a></p><h2 id="structure-of-the-out-folder" class="Styles-hoverBox">Structure of the <code>out/</code> folder<a href="#structure-of-the-out-folder" class=" Styles-hoverLink"><i class="fa fa-link" aria-hidden="true"></i></a></h2>
<p>The <code>out/</code> folder contains all the generated files & metadata for your build. It is structured with one folder per <code>Target</code>/<code>Command</code>, that is run, e.g.:</p>
<ul>
<li><code>out/core/compile/</code></li>
<li><code>out/main/test/compile/</code></li>
<li><code>out/main/test/forkTest/</code></li>
<li><code>out/scalalib/compile/</code></li>
</ul>
<p>There are also top-level build-related files in the <code>out/</code> folder, prefixed as <code>mill-*</code>. The most useful is <code>mill-profile.json</code>, which logs the tasks run and time taken for the last Mill command you executed. This is very useful if you want to find out exactly what tasks are being run and Mill is being slow.</p>
<p>Each folder currently contains the following files:</p>
<ul>
<li>
<p><code>dest/</code>: a path for the <code>Task</code> to use either as a scratch space, or to place generated files that are returned using <code>PathRef</code>s. <code>Task</code>s should only output files within their given <code>dest/</code> folder (available as <code>T.ctx().dest</code>) to avoid conflicting with other <code>Task</code>s, but files within <code>dest/</code> can be named arbitrarily.</p></li>
<li>
<p><code>log</code>: the <code>stdout</code>/<code>stderr</code> of the <code>Task</code>. This is also streamed to the console during evaluation.</p></li>
<li>
<p><code>meta.json</code>: the cache-key and JSON-serialized return-value of the <code>Target</code>/<code>Command</code>. The return-value can also be retrieved via <code>mill show
core.compile</code>. Binary blobs are typically not included in <code>meta.json</code>, and instead stored as separate binary files in <code>dest/</code> which are then referenced by <code>meta.json</code> via <code>PathRef</code>s</p></li>
</ul>
<p>The <code>out/</code> folder is intentionally kept simplistic and user-readable. If your build is not behaving as you would expect, feel free to poke around the various <code>dest/</code> folders to see what files are being created, or the <code>meta.json</code> files to see what is being returned by a particular task. You can also simply delete folders within <code>out/</code> if you want to force portions of your project to be re-built, e.g. deleting the <code>out/main/</code> or <code>out/main/test/compile/</code> folders.</p><h2 id="overriding-mill-versions" class="Styles-hoverBox">Overriding Mill Versions<a href="#overriding-mill-versions" class=" Styles-hoverLink"><i class="fa fa-link" aria-hidden="true"></i></a></h2>
<p>Apart from downloading and installing new versions of Mill globally, there are a few ways of selecting/updating your Mill version:</p>
<ul>
<li>Create a <code>.mill-version</code> file to specify the version of Mill you wish to use:</li>
</ul>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="bash">echo "0.5.0" > .mill-version
</code></pre>
<p><code>.mill-version</code> takes precedence over the version of Mill specified in the <code>./mill</code> script.</p>
<ul>
<li>ass in a <code>MILL_VERSION</code> environment variable, e.g.</li>
</ul>
<pre style="background-color: #f8f8f8"><code style="white-space:pre; background-color: #f8f8f8" class="bash">MILL_VERSION=0.5.0-3-4faefb mill __.compile
```
or
</code></pre>
<p>MILL_VERSION=0.5.0-3-4faefb ./mill __.compile ```</p>
<p>to override the Mill version manually. This takes precedence over the version specified in <code>./mill</code> or <code>.mill-version</code></p>
<p>Note that both of these overrides only work for versions 0.5.0 and above.</p><h3 id="development-releases" class="Styles-hoverBox">Development Releases<a href="#development-releases" class=" Styles-hoverLink"><i class="fa fa-link" aria-hidden="true"></i></a></h3>
<p>In case you want to try out the latest features and improvements that are currently in master, unstable versions of Mill are <a href="https://github.com/lihaoyi/mill/releases">available</a> as binaries named <code>#.#.#-n-hash</code> linked to the latest tag. Installing the latest unstable release is recommended for bootstrapping mill.</p>
<p>The easiest way to use a development release is by updating the <a href="#bootstrap-scripts-linuxos-x-only">Bootstrap Script</a>, or <a href="#overriding-mill-versions">Overriding Mill Versions</a> via an environment variable or <code>.mill-version</code> file.</p>
<p>Come by our <a href="https://gitter.im/lihaoyi/mill">Gitter Channel</a> if you want to ask questions or say hi!</p><hr /><p><b>About the Author:</b><i> Haoyi is a software engineer, an early contributor to <a href="http://www.scala-js.org/">Scala.js</a>, and the author of many open-source Scala tools such as Mill, the <a href="http://lihaoyi.com/Ammonite">Ammonite REPL</a> and <a href="https://github.com/lihaoyi/fastparse">FastParse</a>. </i></p><p><i>If you've enjoy using Mill, or enjoyed using Haoyi's other open source libraries, please chip in (or get your Company to chip in!) via <a href="https://www.patreon.com/lihaoyi">Patreon</a> so he can continue his open-source work</i></p><hr /><div style="display: flex;flex-direction: row;justify-content: space-between;"><div></div><a href="page/configuring-mill.html">Configuring Mill <i class="fa fa-arrow-right" aria-hidden="true"></i></a></div></div></body></html>
|
