Better support for dumb terminals

[jglick]

Split from #116. Emacs 26.3. M-x shell produces a quasi-shell with

$ echo $TERM
emacs

ANSI highlighting is supported, as well as simple cursor movement (so for example dynamic display from git pull works fine). mvnd’s dynamic display gets mangled, though; some attempt to move between lines is just too much:

$ mvnd -f …/jenkinsci/build-token-root-plugin clean verify
Building...
build-token-root:<unknown>:build-token-root         :org.apache.maven.plugins:maven-clean-plugin:3.1.0:clean {execution: default-clean}jenkins-ci.tools:maven-hpi-plugin:3.15:validate {execution: default-validate  }apache.maven.plugins:maven-enforcer-plugin:3.0.0-M3:display-info {execution: display-info }enforce                                {execution: display-info}no-snapshots-in-release }codehaus.gmavenplus:gmavenplus-plugin:1.10.1:addTestSources {execution: test-in-groovy          }jvnet.localizer:maven-localizer-plugin:1.26:generate {execution: default               }apache.maven.plugins:maven-resources-plugin:3.2.0:resources {execution: default-resources }compiler-plugin:3.8.1:compile {execution: default-compile      }kohsuke:access-modifier-checker:1.16:enforce {execution: default-enforc              e}jenkins-ci.tools:maven-hpi-plugin:3.15:insert-test {execution: default-insert-test }codehaus.gmavenplus:gmavenplus-plugin:1.10.1:generateTestStubs {execution: test-in-groovy }apache.maven.plugins:maven-antrun-plugin:3.0.0:run {execution: createTempDir              }resources-plugin:3.2.0:testResources {execution: default-testResourcecompiler-plugin:3.8.1:testCompile {execution: default-testCompile}   jenkins-ci.tools:maven-hpi-plugin:3.15:test-hpl {execution: default-test-hpl                 }resolve-test-dependencies {execution: default-resolve-tescodehaus.gmavenplus:gmavenplus-plugin:1.10.1:compileTests {execution: test-in-groovy}           apache.maven.plugins:maven-surefire-plugin:3.0.0-M4:test {execution: default-test    }codehaus.mojo:animal-sniffer-maven-plugin:1.19:check {execution: check            }com.cloudbees:maven-license-plugin:1.8:process {execution: default         }org.jenkins-ci.tools:maven-hpi-plugin:3.15:hpi {execution: default-hpi }apache.maven.plugins:maven-jar-plugin:3.2.0:test-jar {execution: maybe-test-jar }com.github.spotbugs:spotbugs-maven-plugin:4.0.4:spotbugs {execution: spotbugs       }check                          {execution: spotbugs}build-token-root:<unknown>                                                                              
                          [INFO] Scanning for projects...
[INFO] BuildTimeEventSpy is registered.
[INFO] 
[INFO] Using the SmartBuilder implementation with a thread count of 12
[INFO] Task segments : [clean, verify]
[INFO] Build maximum degree of concurrency is 12
[INFO] Total number of projects is 1
[INFO] 
[INFO] --------------< org.jenkins-ci.plugins:build-token-root >---------------
[INFO] Building Build Authorization Token Root Plugin 1.8-SNAPSHOT
[INFO] --------------------------------[ hpi ]---------------------------------
[INFO] 
[INFO] --- maven-clean-plugin:3.1.0:clean (default-clean) @ build-token-root ---
…
[INFO] --- spotbugs-maven-plugin:4.0.4:check (spotbugs) @ build-token-root ---
[INFO] BugInstance size is 0
[INFO] Error size is 0
[INFO] No errors/warnings found
[INFO] Segment walltime 21 s, segment projects service time 21 s, effective/maximum degree of concurrency 1.00/12
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  21.491 s (Wall Clock)
[INFO] Finished at: 2020-10-23T04:30:54-04:00
[INFO] ------------------------------------------------------------------------

(The full build log looks fine, including colorization.)

[jglick]

Just noticed that the fancy output is turned on even when TERM=dumb, or for that matter when stdout is not a tty, like when you pipe to some other tool. Commands using ANSI magic need to disable that automatically when appropriate.

[gnodet]

That's right, we should change the output method when the created terminal is a dumb one.

[gnodet]

Fwiw, mvnd runs fine in Emacs term mode M-x term.

[ppalaga]

Can we close this then?

[gnodet]

Can we close this then?

No, I think we should definitely make mvnd smarter and adapt to the fact that the terminal is dumb. In the emacs M-x shell, it's not completely dumb though as it does support ANSI coloring, so we don't necessarily have to strip those. But we do need to avoid the multi-thread logging somehow.

[jglick]

Note that for multimodule projects I still need to pass --serial to get reasonable output.