Fix #4240: 旧版MC日志把每一条都给算成error

[Wulian233]

update：下面评论所有的版本都解决了

Close #4240

老版本日志的级别都是本地化中文的，所以还需要根据这个判断日志级别，不能不改Log4jLevel.java，否则全部日志都会变成信息级别

[woshixiaoheizi114514]

艹，竟然有人想起来这条issue

[woshixiaoheizi114514]

实际上原版1.6.4日志也是全算成error（info一觉起来成error）的。。。

(虽然我更多时候遇到此类情况并不是1.6.4forge，而是MITE模组)

[woshixiaoheizi114514]

后面又测了几个版本，1.5.2也是这种结构，但是再早（从1.1开始）就是图一这种了（艹上传顺序反了）

[Wulian233]

你能给一个所有日志都被算为error的一个版本范围吗

[woshixiaoheizi114514]

阿尔法1.0.1也有

[woshixiaoheizi114514]

正在找最早能实现的版本ing（因为rd版本日志已经没啥用了）

[woshixiaoheizi114514]

目前理论最早出现的是classic0.0.11a(貌似是镜像源能下到最早的classic了)

[Wulian233]

update：上面评论所有的版本都解决了，可以随时审查合并

[Wulian233]

/gemini review

[gemini-code-assist]

Code Review

This pull request refactors the log level guessing logic in Log4jLevel.java by introducing helper methods and predefined marker arrays to simplify the parsing code. It also updates LauncherHelper.java to leverage these new methods. The review identified two critical issues: first, redundant calls to guessLevel in LauncherHelper.java that degrade performance and can lead to a potential NullPointerException when level remains null; second, a regression in Log4jLevel.java where the check for [STDERR] was omitted during the refactoring of error markers.

Important

The consumer version of Gemini Code Assist on GitHub is being sunset. Starting June 18, 2026, new organization installations will be blocked, and all code review activity will officially cease on July 17, 2026.
For more details on the timeline and next steps, please review the Help Documentation.

[Wulian233]

/gemini review

[gemini-code-assist]

Code Review

This pull request refactors the log level guessing logic in Log4jLevel.java by introducing helper methods and predefined marker arrays to simplify parsing. In LauncherHelper.java, the log level guessing is updated to handle error streams. The review feedback highlights two improvement opportunities: first, Level.getLocalizedName() depends on the JVM locale and may fail to match Chinese localized logs on non-Chinese systems, so explicit Chinese markers should be added; second, there is a redundant call to Log4jLevel.guessLevel(log) in LauncherHelper.java when level is already determined to be null, which can be simplified to directly use Log4jLevel.INFO.

Important

The consumer version of Gemini Code Assist on GitHub is being sunset. Starting June 18, 2026, new organization installations will be blocked, and all code review activity will officially cease on July 17, 2026.
For more details on the timeline and next steps, please review the Help Documentation.

[gemini-code-assist]

在 LauncherHelper.java 中，如果 level 为 null，代码会再次调用 Log4jLevel.guessLevel(log)。然而，在第 937-939 行中，level 已经是通过 Log4jLevel.guessLevel 计算出来的。如果它为 null，再次调用也必然返回 null。

因此，这里可以直接使用 Log4jLevel.INFO 作为默认值，避免重复进行正则匹配，从而提高日志处理的效率。

Suggested change

	Log4jLevel level = log.startsWith("[authlib-injector]")
	? Log4jLevel.guessLevel(log)
	: Log4jLevel.guessLevel(log, isErrorStream);
	if (showLogs) {
	if (level == null)
	level = Lang.requireNonNullElse(Log4jLevel.guessLevel(log), Log4jLevel.INFO);
	Log4jLevel level = log.startsWith("[authlib-injector]")
	? Log4jLevel.guessLevel(log)
	: Log4jLevel.guessLevel(log, isErrorStream);
	if (showLogs) {
	if (level == null)
	level = Log4jLevel.INFO;