refactor: share NuGet config structure with hosted rewrites

Author: mikolalysenko

crates/socket-patch-cli/tests/e2e_nuget_dotnet_build.rs

@@ -752,6 +752,19 @@ fn nuget_hosted_dotnet_restore_then_manifestless_vex() {
     let store_fx = sb.dir("store-fixture");
     let registry = restore_fixture(&dn, &sb, &fixture, &store_fx);
 
+    // Regression #561/#585: templates often keep inactive sources/mappings.
+    // A forward rewrite must agree with NuGet and VEX about which XML is live.
+    let inactive = "<!-- <packageSources><add key=\"old\" value=\"https://old.invalid/v3/index.json\" /></packageSources><packageSourceMapping></packageSourceMapping> -->";
+    std::fs::write(
+        fixture.join("nuget.config"),
+        registry.0.replacen(
+            "<configuration>",
+            &format!("<configuration>\n  {inactive}"),
+            1,
+        ),
+    )
+    .unwrap();
+
     let pristine = std::fs::read(pkg_dir(&store_fx).join(FILE_KEY)).unwrap();
     let mut patched = pristine.clone();
     patched.extend_from_slice(MARKER);
@@ -794,6 +807,10 @@ fn nuget_hosted_dotnet_restore_then_manifestless_vex() {
     let doc: Value = serde_json::from_slice(&std::fs::read(&embedded).unwrap()).unwrap();
     assert_attested(&doc, PURL, HOSTED_UUID, Marker::Redirected, &vulns());
     let config = std::fs::read_to_string(fixture.join("nuget.config")).unwrap();
+    assert!(
+        config.contains(inactive),
+        "inactive XML left byte-exact: {config}"
+    );
     assert!(
         config.contains(&format!("socket-patch-{HOSTED_UUID}"))
             && config.contains(&format!("pattern=\"{ID}\"")),

crates/socket-patch-core/src/formats/nuget/mod.rs

@@ -11,6 +11,7 @@
 //! attribute or a mismatched close tag makes the whole file `None`.
 
 use std::collections::BTreeSet;
+use std::ops::Range;
 
 // ── pure reader ──
 
@@ -28,6 +29,47 @@ pub(crate) struct NugetConfig {
     pub(crate) mappings: Vec<(String, Vec<String>)>,
     /// Keys `configuration/disabledPackageSources` turns off.
     pub(crate) disabled: BTreeSet<String>,
+    /// Live XML locations for writers. Routing readers and writers share
+    /// the same treatment of comments, quoted attributes and element scope.
+    pub(crate) configuration: Option<ConfigSection>,
+    pub(crate) package_sources: Option<ConfigSection>,
+    pub(crate) source_mapping: Option<ConfigSection>,
+    /// Preserve the routing reader's behavior on repeated sections, but do
+    /// not let a writer guess which occurrence should receive an edit.
+    pub(crate) repeated_sections: bool,
+}
+
+#[derive(Debug)]
+pub(crate) struct ConfigSection {
+    pub(crate) open: Range<usize>,
+    /// `None` for a self-closing element (unclosed XML fails parsing).
+    pub(crate) close_start: Option<usize>,
+    /// After the last direct `<clear>` child, or the opening tag otherwise.
+    pub(crate) insert_at: usize,
+}
+
+fn section_mut<'a>(
+    cfg: &'a mut NugetConfig,
+    parents: &[&str],
+    name: &str,
+) -> Option<&'a mut Option<ConfigSection>> {
+    match (parents, name) {
+        ([], "configuration") => Some(&mut cfg.configuration),
+        (["configuration"], "packageSources") => Some(&mut cfg.package_sources),
+        (["configuration"], "packageSourceMapping") => Some(&mut cfg.source_mapping),
+        _ => None,
+    }
+}
+
+fn record_clear(cfg: &mut NugetConfig, parents: &[&str], end: usize) {
+    let section = match parents {
+        ["configuration", "packageSources"] => cfg.package_sources.as_mut(),
+        ["configuration", "packageSourceMapping"] => cfg.source_mapping.as_mut(),
+        _ => None,
+    };
+    if let Some(section) = section {
+        section.insert_at = end;
+    }
 }
 
 /// One open (or self-closing) tag.
@@ -68,13 +110,33 @@ pub(crate) fn parse_config(text: &str) -> Option<NugetConfig> {
             i = at + rest.find('>')? + 1;
         } else if let Some(close) = rest.strip_prefix("</") {
             let end = close.find('>')?;
-            if stack.pop()? != close[..end].trim() {
+            let name = stack.pop()?;
+            if name != close[..end].trim() {
                 return None;
             }
             i = at + 2 + end + 1;
+            if let Some(Some(section)) = section_mut(&mut cfg, &stack, name) {
+                section.close_start = Some(at);
+            }
+            if name == "clear" {
+                record_clear(&mut cfg, &stack, i);
+            }
         } else {
             let (tag, consumed) = parse_open_tag(&rest[1..])?;
             i = at + 1 + consumed;
+            if let Some(slot) = section_mut(&mut cfg, &stack, tag.name) {
+                let repeated = slot
+                    .replace(ConfigSection {
+                        open: at..i,
+                        close_start: None,
+                        insert_at: i,
+                    })
+                    .is_some();
+                cfg.repeated_sections |= repeated;
+            }
+            if tag.name == "clear" && tag.self_closing {
+                record_clear(&mut cfg, &stack, i);
+            }
             visit(&stack, &tag, &mut cfg, &mut open_mapping);
             if !tag.self_closing {
                 if stack.len() >= MAX_XML_DEPTH {