Improve enforcer rule error messages #343

elharo · 2025-01-09T11:50:55Z

Avoid abbreviations
Increase test coverage
Make messages platform independent
Don't double print paths to files
Verify test setup with assumptions rather than asserts

slawekjaranowski · 2025-01-13T15:07:36Z

enforcer-rules/src/main/java/org/apache/maven/enforcer/rules/files/AbstractRequireFiles.java

        StringBuilder buf = new StringBuilder();
        if (message != null) {
-            buf.append(message + System.lineSeparator());
+            buf.append(message + '\n');


I'm not sure how it will be worked on windows console ....
Can anybody confirm ...
@michael-o @Bukama

Agree, this isn't right

Note that this method does not print anything on the console. It throws an exception object that should be identical regardless of the platform that creates it. Where this message goes is outside the scope of this class. It might be written to a log file and never show up on a console. It might be suppressed completely.

In 2025 Windows shells behave in the obvious way if you send them a linefeed, so this works just fine across platforms if someone does happen to print this string to a console. Maybe System.lineSeparator was needed in Windows 95. It isn't now.

at least jshell handles them the same.

but not cmd

Are you sure about cmd on Windows 10+? I don't have a Windows system handy to test but I asked Gemini and it claims:

The Windows Command Prompt (cmd.exe) shell is typically configured to interpret a single Line Feed character (\n or ASCII 0x0A) as a full line break, even though the native Windows line-ending convention is Carriage Return followed by Line Feed (\r\n or ASCII 0x0D 0x0A).

Therefore, when a Java program sends a string containing only \n characters to the cmd console (via System.out.print or System.err.print):

The text will display on new lines correctly. The console window handles the single \n and translates it for proper display, moving the cursor to the beginning of the next line.

No display issues like "stair-stepping" will occur. The cursor will not get "stuck" at the end of the previous line without returning to the left margin.

The Key Distinction

The behavior depends on where the output is being sent:

Destination Line Ending Behavior Result for \n Only

Console/Shell (cmd.exe window) The console driver interprets the \n and correctly advances the cursor to the start of the next line. Correct Multiline Display

Plain Text File (using redirection like > file.txt) The stream is often treated as raw bytes, and the file system retains the single \n (Unix-style). Single Line Feed is preserved. Text editors like Notepad (pre-Windows 10) may show the output as a single, long line or with empty boxes for the missing \r. Modern editors (VS Code, Notepad++, and newer Windows Notepad) will display it correctly.

In summary, when printing directly to the cmd window, the Java \n will result in a clean, new line.

michael-o · 2025-01-13T15:13:49Z

enforcer-rules/src/main/java/org/apache/maven/enforcer/rules/files/AbstractRequireFiles.java

        StringBuilder buf = new StringBuilder();
        if (message != null) {
-            buf.append(message + System.lineSeparator());
+            buf.append(message + '\n');


Agree, this isn't right

Bukama · 2025-01-13T16:49:37Z

Build (mvn clean verify site) of this branch breaks (on Windows 10): Please have a look.

[INFO] Reactor Summary for Apache Maven Enforcer 3.6.0-SNAPSHOT:
[INFO]
[INFO] Apache Maven Enforcer ................................................................................ SUCCESS [ 28.782 s]
[INFO] Apache Maven Enforcer API ............................................................................ SUCCESS [  4.314 s]
[INFO] Apache Maven Enforcer Built-In Rules ................................................................. SUCCESS [ 13.093 s]
[INFO] Apache Maven Enforcer Plugin ......................................................................... FAILURE [ 10.733 s]
[INFO] Apache Maven Enforcer Extension ...................................................................... SKIPPED
[INFO] --------------------------------------------------------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] --------------------------------------------------------------------------------------------------------------------------
[INFO] Total time:  57.264 s
[INFO] Finished at: 2025-01-13T17:27:56+01:00
[INFO] --------------------------------------------------------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-site-plugin:3.12.1:site (default-site) on project maven-enforcer-plugin: Error generating maven-plugin-report-plugin:3.13.1:report report: Cannot invoke "org.codehaus.plexus.configuration.PlexusConfiguration.getChild(String)" because "this.configuration" is null -> [Help 1]

>mvn --version
Apache Maven 4.0.0-rc-2 (273314404f85ec3c089e295d8b4e0cb18c287cf5)
Maven home: C:\apache-maven-4.0.0-rc-2
Java version: 21.0.1, vendor: Eclipse Adoptium, runtime: C:\JDK\Java21
Default locale: de_DE, platform encoding: UTF-8
OS name: "windows 10", version: "10.0", arch: "amd64", family: "windows"```

Bukama · 2025-01-13T16:50:07Z

...cer-rules/src/test/java/org/apache/maven/enforcer/rules/files/TestRequireFilesDontExist.java

-import static org.junit.jupiter.api.Assertions.assertNotNull;
-import static org.junit.jupiter.api.Assertions.assertTrue;
-import static org.junit.jupiter.api.Assertions.fail;
+import static org.junit.jupiter.api.Assertions.*;


Is the introduction of star imports on purpose? (here and in other test files)

should was be catched by checkstyle ... 🤔

apache/maven-parent#228

no, not intentional. Let me fix it.

slawekjaranowski · 2025-01-13T16:56:54Z

@Bukama site is broken for all maven-plugins and Maven 4.x
https://issues.apache.org/jira/browse/MPLUGIN-502

slawekjaranowski · 2025-02-01T12:14:21Z

enforcer-rules/src/test/java/org/apache/maven/enforcer/rules/files/TestRequireFilesSize.java

-        assertFalse(f.exists());
+        assumeFalse(f.exists());


It will change test logic ... at all
When file will be not deleted .. test will be marked as skipped not failed

Is it intentional?

Yes, we don't want to test that the JDK's delete method works as expected, and if the code under test isn't even executed then the test has been skipped, not failed. This case inspired me to write https://cafe.elharo.com/testing/assume-vs-assert/

elharo

PTAL

elharo · 2025-02-20T13:24:46Z

Ping

Bukama · 2025-02-21T12:44:32Z

...cer-rules/src/test/java/org/apache/maven/enforcer/rules/files/TestRequireFilesDontExist.java

        f.delete();

-        assertFalse(f.exists());
+        assumeTrue(f.exists());


I don't get this one. The file is shall not be there (method name says and f.delete) but you assume it exists?

It's a mistake. Fixed

slawekjaranowski

We need use a system specific line separator ....

github-actions · 2025-08-07T04:48:06Z

This pull request is stale because it has been waiting for feedback for 60 days. Remove the stale label or comment on this PR, or it will be automatically closed in 30 days.

elharo added 2 commits January 9, 2025 06:50

Make exception messages platform independent

78dd344

tests

d1fa7a2

elharo changed the title ~~Make exception messages platform independent~~ Improve enforcer rule error messages Jan 9, 2025

elharo marked this pull request as ready for review January 12, 2025 14:16

elharo requested review from khmarbaise and slawekjaranowski January 12, 2025 14:17

slawekjaranowski reviewed Jan 13, 2025

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michael-o requested changes Jan 13, 2025

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elharo added 5 commits January 13, 2025 13:01

import

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Merge branch 'master' into line

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imports

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no wildcard imports

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no wildcard imports

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elharo commented Feb 1, 2025

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spotless

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elharo added 2 commits September 29, 2025 07:57

merge master

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import

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Destination	Line Ending Behavior	Result for `\n` Only
Console/Shell (`cmd.exe` window)	The console driver interprets the `\n` and correctly advances the cursor to the start of the next line.	Correct Multiline Display
Plain Text File (using redirection like `> file.txt`)	The stream is often treated as raw bytes, and the file system retains the single `\n` (Unix-style).	Single Line Feed is preserved. Text editors like Notepad (pre-Windows 10) may show the output as a single, long line or with empty boxes for the missing `\r`. Modern editors (VS Code, Notepad++, and newer Windows Notepad) will display it correctly.

Improve enforcer rule error messages #343

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Improve enforcer rule error messages #343

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elharo commented Jan 9, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Bukama Feb 21, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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The Key Distinction

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Bukama commented Jan 13, 2025

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elharo commented Jan 9, 2025 •

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