logger.info() messages should not be sent to stderr

[fcrwx]

🐞 Bug report

Command (mark with an x)

• new
• build
• serve
• test
• e2e
• generate
• add
• update
• lint
• xi18n
• run
• config
• help
• version
• doc

Is this a regression?

No

Description

logger.info() statements from ngcc are sent to stderr causing the informational messages to be displayed (in red) as ERRORs under a maven build. Please see the rejected PR at angular/angular#35310 which documents the incorrect behavior. The ngcc team believes this should be fixed in the cli.

🔬 Minimal Reproduction

In maven's pom.xml:

  ...
  <execution>
    <id>npm angular build</id>
      <goals>
        <goal>npm</goal>
      </goals>
      <configuration>
        <arguments>run build-dev</arguments>
      </configuration>
  </execution>
  ...

In package.json:

    "scripts": {
        ...
        "build-dev": "ng build",
        ...
    },

🔥 Exception or Error

Output from maven build:

[INFO] > ng build
[INFO]
[ERROR]
[ERROR] Compiling @angular/core : module as esm5
[ERROR]
[ERROR] Compiling @angular/common : module as esm5
[ERROR]
[ERROR] Compiling @angular/platform-browser : module as esm5
[ERROR]
[ERROR] Compiling @angular/platform-browser-dynamic : module as esm5
[ERROR]
...

🌍 Your Environment

Angular CLI: 9.0.1
Node: 12.13.1
OS: darwin x64

Angular: 9.0.0
... animations, cdk, common, compiler, compiler-cli, core, forms
... language-service, material, platform-browser
... platform-browser-dynamic, router, upgrade
Ivy Workspace: Yes

Package                           Version
-----------------------------------------------------------
@angular-devkit/architect         0.900.1
@angular-devkit/build-angular     0.900.1
@angular-devkit/build-optimizer   0.900.1
@angular-devkit/build-webpack     0.900.1
@angular-devkit/core              9.0.1
@angular-devkit/schematics        9.0.1
@angular/cli                      9.0.1
@angular/flex-layout              9.0.0-beta.29
@ngtools/webpack                  9.0.1
@schematics/angular               9.0.1
@schematics/update                0.900.1
rxjs                              6.5.4
typescript                        3.7.5
webpack                           4.41.2

Anything else relevant?

[alan-agius4]

Progress, diagnostic and status messages should be written to stderr. stdout should only be used for logs intended to be piped to another command.

//cc @clydin as he definitely has more stronger arguments why it should be stderr.

[alan-agius4]

Most likely we should offer a way to silence these, maybe hide the logs when using the no-progress or only show them in verbose mode.

Related to #16899

[clydin]

Is frontend-maven-plugin being used in that maven pom? If so, than version 1.8.0+ (changelog & related issue) appears to contain a fix so that it does not assume that anything written to stderr is an error. stderr is intended as a general vehicle for diagnostic information and should not be assumed to indicate an error.

[fcrwx]

@clydin - Thank you! Upgrading frontend-maven-plugin from 1.7.6 to 1.8.0 resolves the issue:

[INFO] --- frontend-maven-plugin:1.8.0:npm (npm angular build) @ newton-frontend ---
[INFO] Running 'npm run build-dev' in /Users/kolson/dev/Newton/webapps/newton-frontend
[INFO]
[INFO] > [email protected] build-dev /Users/kolson/dev/Newton/webapps/newton-frontend
[INFO] > ng build
[INFO]
[INFO]
[INFO] Compiling @angular/core : module as esm5
[INFO]
[INFO] Compiling @angular/common : module as esm5
[INFO]
[INFO] Compiling @angular/platform-browser : module as esm5
[INFO]
[INFO] Compiling @angular/platform-browser-dynamic : module as esm5
[INFO]
[INFO] Compiling @angular/upgrade/static : module as esm5
...

[clydin]

Good to hear. Since the issue appears to be resolved, I'm going to close.

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