Eclipse不一致：资源泄漏：'< unssigned Closeable value>'永远不会关闭 [英] Eclipse inconsistencies: Resource leak: '<unassigned Closeable value>' is never closed

问题描述

如果我有以下代码：

public OutputStream test(boolean condition) throws FileNotFoundException {
    return condition ? null : new FileOutputStream("test.txt");
}

Eclipse将黄色字形置于 new FileOutputStream（ test .txt）并向我显示以下警告：

Eclipse puts yellow squiggles under new FileOutputStream("test.txt") and shows me the following warning:

资源泄漏：< unssigned Closeable value>永远不会关闭

奇怪的是，如果我删除三元运算，则：

The strange thing is, if I remove the ternary operation:

public OutputStream test() throws FileNotFoundException {
    return new FileOutputStream("test.txt");
}

警告消失了。

这是Eclipse中的不一致（错误吗？）还是缺少两种情况之间的根本区别？

Is this an inconsistency (bug?) in Eclipse or am I missing some fundamental difference between the two scenarios?

通常，Eclipse似乎很聪明足以理解当我返回 Closeable ，不让该方法关闭流是可以的（毕竟，返回关闭的流有什么意义？）。当我间接返回结果时，它甚至可以正确执行此操作：

In general, it seems like Eclipse is smart enough to understand that when I return a Closeable from a method, it is ok to not have the method close the stream (after-all, what's the point of returning a closed stream?). It even does this correctly when I return the result indirectly:

public OutputStream test() throws FileNotFoundException {
    FileOutputStream result = new FileOutputStream("test.txt");
    return result;
}

（此处无警告）

那么，Eclipse是否只是被三元操作所迷惑？如果是这样，我应该将其报告为错误吗？

So, is Eclipse just getting confused by the ternary operation? If so, should I report this as a bug?

另一件奇怪的事情：

如果我替换 FileOutputStream 和 ByteArrayOutputStream ，警告也消失了：

If I replace FileOutputStream with ByteArrayOutputStream, the warning goes away also:

public OutputStream test(boolean condition) {
    return condition ? null : new ByteArrayOutputStream();
}

如何区别对待这两个流？两者都是 OutputStream 并实现完全相同的接口（ 可关闭 ， Flushable ， AutoCloseable ）。是否以某种方式知道 ByteArrayOutputStream.close（） 是没有操作的吗？如果是这样，是将它硬编码到Eclipse中，还是实际上是解析源代码或字节码来解决这个问题？

How come it's treating these two streams differently? Both are direct descendents of OutputStream and implement the exact same interfaces (Closeable, Flushable, AutoCloseable). Does it somehow know that ByteArrayOutputStream.close() is a no-op? If so, is that hard-coded into Eclipse or does it actually parse the source or byte-code to figure this out?

推荐答案

这显然是一个错误。错误报告 https://bugs.eclipse.org/bugs/show_bug.cgi ？id = 434065 已被确认，但没有得到解决。

It is clearly a bug. The bug report https://bugs.eclipse.org/bugs/show_bug.cgi?id=434065 has been acknowledged, but not fixed.

该错误截至2019年7月仍未解决。

The bug is still open as of July 2019.

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