Quick fix "Add throws declaration" removes backslashes and qute fragments

[LukasLeppich]

There are some unwanted changes made by the "Add throws declaration" Quick fix action.

If you use the QuickFix action Add throws declarat... the java extension will remove the fragment name of the second Template specification and the escaped backslashes from the string.

Before executing the QuickFix:

    String someString = "Escaped\\Test\\Path";

    @CheckedTemplate
    static class Templates {
        public static native TemplateInstance page();
        public static native TemplateInstance page$content();
    }

After performing the QuickFix:

    String someString = "Escaped\Test\Path";

    @CheckedTemplate
    static class Templates {
        public static native TemplateInstance page();
        public static native TemplateInstance page();
    }

Steps to reproduce:

1. Clone reproducer repository: https://github.com/LukasLeppich/vscode-java-quickfix-bug
2. Create a new VSCode Profile
3. Install the Extension Pack for Java extension
4. Open the SomePage.java class and perform the Add throws declarat... Quick Fix on line 30 service.test();

Tested with the following setup:

Vscode:
Version: 1.108.1 (user setup)
Commit: 585eba7c0c34fd6b30faac7c62a42050bfbc0086
Date: 2026-01-14T14:55:44.241Z

Extensions:
redhat.java@1.51.0
vscjava.vscode-gradle@3.17.2
vscjava.vscode-java-debug@0.58.5
vscjava.vscode-java-dependency@0.27.0
vscjava.vscode-java-pack@0.30.5
vscjava.vscode-java-test@0.44.0
vscjava.vscode-maven@0.45.1

[fbricon]

Can't reproduce it in Eclipse IDE, meaning it's a bug in JDT.LS

[fbricon]

When resolving the code action, the server returns

[Trace - 10:57:51 AM] Received response 'codeAction/resolve - (665)' in 9ms.
Result: {
    "title": "Add throws declaration",
    "kind": "quickfix",
    "diagnostics": [
        {
            "range": {
                "start": {
                    "line": 28,
                    "character": 8
                },
                "end": {
                    "line": 28,
                    "character": 22
                }
            },
            "severity": 1,
            "code": "16777384",
            "source": "Java",
            "message": "Unhandled exception type ExecutionException"
        }
    ],
    "edit": {
        "changes": {},
        "documentChanges": [
            {
                "textDocument": {
                    "version": null,
                    "uri": "file:///Users/fbricon/Dev/souk/quickfix-bug/src/main/java/org/acme/SomePage.java"
                },
                "edits": [
                    {
                        "snippet": {
                            "value": "import java.util.concurrent.ExecutionException;\n\nimport io.quarkus.qute.CheckedTemplate;\nimport io.quarkus.qute.TemplateInstance;\nimport jakarta.ws.rs.GET;\nimport jakarta.ws.rs.Path;\nimport jakarta.ws.rs.Produces;\nimport jakarta.ws.rs.core.MediaType;\n\n@Path(\"/some-page\")\npublic class SomePage {\n    \n    String someString = \"Escaped\\\\Test\\\\Path\";\n\n    static class Templates {\n        public static native TemplateInstance page();\n        public static native TemplateInstance page$content();\n    }\n    \n    private Service service;\n    public SomePage() {\n    }\n\n    @GET\n    @Produces(MediaType.TEXT_HTML)\n    public TemplateInstance get() throws ${1|ExecutionException,Exception,Throwable|}"
                        },
                        "range": {
                            "start": {
                                "line": 4,
                                "character": 0
                            },
                            "end": {
                                "line": 27,
                                "character": 33
                            }
                        },
                        "newText": ""
                    }
                ]
            }
        ]
    }
}

I suspect that, because it's a snippet, VS Code goes through another pass at unescaping backslashes and dollar signs, and ends up applying

[Trace - 10:57:51 AM] Sending notification 'textDocument/didChange'.
Params: {
    "textDocument": {
        "uri": "file:///Users/fbricon/Dev/souk/quickfix-bug/src/main/java/org/acme/SomePage.java",
        "version": 66
    },
    "contentChanges": [
        {
            "range": {
                "start": {
                    "line": 4,
                    "character": 0
                },
                "end": {
                    "line": 27,
                    "character": 33
                }
            },
            "rangeLength": 593,
            "text": "import java.util.concurrent.ExecutionException;\n\nimport io.quarkus.qute.CheckedTemplate;\nimport io.quarkus.qute.TemplateInstance;\nimport jakarta.ws.rs.GET;\nimport jakarta.ws.rs.Path;\nimport jakarta.ws.rs.Produces;\nimport jakarta.ws.rs.core.MediaType;\n\n@Path(\"/some-page\")\npublic class SomePage {\n    \n    String someString = \"Escaped\\Test\\Path\";\n\n    static class Templates {\n        public static native TemplateInstance page();\n        public static native TemplateInstance page();\n    }\n    \n    private Service service;\n    public SomePage() {\n    }\n\n    @GET\n    @Produces(MediaType.TEXT_HTML)\n    public TemplateInstance get() throws ExecutionException"
        }
    ]
}

[fbricon]

I tried opening the same project in LazyVim and code action was properly applied there. So the problem is vscode client specific.

[Gourav2580]

/assign