Scaladoc 3.3.x falsely reports success despite errors #23561
Description
Compiler version
tested 3.3.4, 3.3.5, 3.3.6, and 3.3.7-RC1-bin-20250709-d743501-NIGHTLY
tested 3.7.1 did not have the bug.
Minimized code
in the affected versions, when a scaladoc error occurs, the error is not propagated to build tools. so, the build tools report a success but the docs output is incorrectly built, and this leads to downstream failures.
scaladoc-does-not-report-errors.tar.gz
to run the example:
tar xaf scaladoc-does-not-report-errors.tar.gz
cd scala-3-project-template
sbt doc && echo 'sbt success'
./mill foo.docJar && echo 'mill success'
Output
the sbt and mill commands above will report "successful" completion, despite the printed error.
because this affects both build tools, and because the issue is not present in 3.7.1, i believe that the bug is in scaladoc not informing the build tool of its errors.
$ sbt doc && echo 'sbt success'
[info] Main Scala API documentation to /tmp/scala-3-project-template/target/scala-3.3.6/api...
-- Error: src/main/scala/Main.scala:23:12 --------------------------------------
23 | println(m.parse(A))pile 0s
| ^^^^^^^^^
|undefined: m.parse # -1: TermRef(TermRef(NoPrefix,val m),parse) at readTasty
1 error found
[info] Main Scala API documentation successful.
[success] Total time: 5 s, completed 18 July 2025, 8:12:34 pm
sbt success$ ./mill foo.docJar && echo 'mill success'
[56/58] foo.compile
[56] [info] compiling 1 Scala source to /tmp/scala-3-project-template/out/foo/compile.dest/classes ...
[56] [info] done compiling
[58/58] foo.docJar
[58] -- Error: /tmp/scala-3-project-template/src/main/scala/Main.scala:23:12 --------
[58] 23 | println(m.parse(A))
[58] | ^^^^^^^^^
[58] |undefined: m.parse # -1: TermRef(TermRef(NoPrefix,val m),parse) at readTasty
[58] 1 error found
[58/58] ============================== foo.docJar ============================== 3s
mill successobserve that the produced folder is incomplete and broken (missing index.html, for example)
$ ls target/scala-3.3.6/api/
favicon.ico fonts hljs images scaladoc.version scripts styles webfontsExpectation
scaladoc 3.3.x should propagate doc errors to the build tool.
if you change the scalaVersion to 3.7.1, both build tools will correctly report a failure.
the mill code that detects errors uses the Reporter#hasErrors method. I believe the bug could come from that being set incorrectly.