depfixer: silence fix_jar() and make it do something

fix_jar() tries to remove an existing Class-Path entry from the jar
manifest by postprocessing the manifest and passing it to `jar -um`.
However, `jar -um` can only add/replace manifest entries, not remove
them, and it also complains loudly when replacing an entry:

    Dec 13, 2022 7:11:19 PM java.util.jar.Attributes read
    WARNING: Duplicate name in Manifest: Manifest-Version.
    Ensure that the manifest does not have duplicate entries, and
    that blank lines separate individual sections in both your
    manifest and in the META-INF/MANIFEST.MF entry in the jar file.

Thus fix_jar() produces one such warning for each entry in the manifest
and accomplishes nothing else.

Use jar -uM instead.  This completely removes the manifest from the jar
and allows adding it back as a normal zip member, fixing fix_jar() and
avoiding the warnings.

Fixes: https://github.com/mesonbuild/meson/issues/10491
Fixes: c70a051e93 ("java: remove manifest classpath from installed jar")

1 files changed, 7 insertions, 0 deletions

diff --git a/test cases/unit/110 classpath/com/mesonbuild/Simple.java b/test cases/unit/110 classpath/com/mesonbuild/Simple.java
new file mode 100644
index 000000000..325a49a21
--- /dev/null
+++ b/test cases/unit/110 classpath/com/mesonbuild/Simple.java
@@ -0,0 +1,7 @@
+package com.mesonbuild;
+
+class Simple {
+    public static void main(String [] args) {
+        System.out.println("Java is working.\n");
+    }
+}