xtask: Get release changes after the commit

In case they were modified right before being committed.

xtask/src/cargo.rs

@@ -154,10 +154,21 @@ impl Package {
         Ok(())
     }
 
-    /// Get the changes for the version.
+    /// Update the changelog for the release of the current version, if needed.
+    pub fn update_changelog(&self, sh: &Shell) -> Result<()> {
+        self.changes_inner(sh, true)?;
+        Ok(())
+    }
+
+    /// Get the changes for the current version.
+    pub fn changes(&self, sh: &Shell) -> Result<String> {
+        self.changes_inner(sh, false)
+    }
+
+    /// Get the changes for the current version.
     ///
-    /// If `update` is `true`, update the changelog for the release of the given version.
-    pub fn changes(&self, sh: &Shell, update: bool) -> Result<String> {
+    /// If `update` is `true`, the changelog is updated if needed.
+    fn changes_inner(&self, sh: &Shell, update: bool) -> Result<String> {
         if self.name == "ruma-macros" {
             // ruma-macros doesn't have a changelog and won't create a tag.
             return Ok(String::new());
@@ -175,10 +186,11 @@ impl Package {
 
         let (update, title_start) = if let Some(pos) = changelog.find(&format!("# {version}\n")) {
             (false, pos)
-        } else if changelog.starts_with(&format!("# {version} (unreleased)\n"))
-            || changelog.starts_with("# [unreleased]\n")
+        } else if update
+            && (changelog.starts_with(&format!("# {version} (unreleased)\n"))
+                || changelog.starts_with("# [unreleased]\n"))
         {
-            (update, 0)
+            (true, 0)
         } else {
             return Err("Could not find version title in changelog".into());
         };

xtask/src/release.rs

@@ -122,16 +122,20 @@ impl ReleaseTask {
             false
         };
 
-        let changes = &self.package.changes(&self.sh, !prerelease && !self.dry_run)?;
-
-        if self.dry_run {
-            println!("Changes:\n{changes}");
+        if !prerelease && !self.dry_run {
+            self.package.update_changelog(&self.sh)?;
         }
 
         if create_commit {
             self.commit()?;
         }
 
+        let changes = &self.package.changes(&self.sh)?;
+
+        if self.dry_run {
+            println!("Changes:\n{changes}");
+        }
+
         self.package.publish(&self.sh, &self.http_client, self.dry_run)?;
 
         let branch = cmd!(&self.sh, "git rev-parse --abbrev-ref HEAD").read()?;