Merge pull request #2643 from cgwalters/rust-2021

rust: Switch to 2021 edition, bump MSRV, a few `format!` updates

tests/inst/Cargo.toml

@@ -2,7 +2,7 @@
 name = "ostree-test"
 version = "0.1.0"
 authors = ["Colin Walters <walters@verbum.org>"]
-edition = "2018"
+edition = "2021"
 
 [workspace]
 

tests/inst/src/destructive.rs

@@ -363,7 +363,7 @@ fn impl_transaction_test<M: AsRef<str>>(
             booted: booted_commit.to_string(),
             orig: sysrepo_obj.resolve_rev(ORIGREF, false)?.unwrap().into(),
             prev: srvrepo_obj
-                .resolve_rev(&format!("{}^", TESTREF), false)?
+                .resolve_rev(&format!("{TESTREF}^"), false)?
                 .unwrap()
                 .into(),
             target: srvrepo_obj.resolve_rev(TESTREF, false)?.unwrap().into(),
@@ -568,7 +568,7 @@ pub(crate) fn itest_transactionality() -> Result<()> {
         ..Default::default()
     };
     with_webserver_in(&srvrepo, &webserver_opts, move |addr| {
-        let url = format!("http://{}", addr);
+        let url = format!("http://{addr}");
         bash!(
             "ostree remote delete --if-exists testrepo
              ostree remote add --set=gpg-verify=false testrepo ${url}",

tests/inst/src/treegen.rs

@@ -31,9 +31,9 @@ pub(crate) fn mkvroot<P: AsRef<Path>>(p: P, v: u32) -> Result<()> {
         std::fs::create_dir_all(p.join(v))?;
     }
     let verpath = p.join("etc/.mkrootversion");
-    write_file(&verpath, &format!("{}", v))?;
-    write_file(p.join("usr/bin/somebinary"), &format!("somebinary v{}", v))?;
-    write_file(p.join("etc/someconf"), &format!("someconf v{}", v))?;
+    write_file(&verpath, &format!("{v}"))?;
+    write_file(p.join("usr/bin/somebinary"), &format!("somebinary v{v}"))?;
+    write_file(p.join("etc/someconf"), &format!("someconf v{v}"))?;
     write_file(p.join("usr/bin/vmod2"), &format!("somebinary v{}", v % 2))?;
     write_file(p.join("usr/bin/vmod3"), &format!("somebinary v{}", v % 3))?;
     Ok(())
@@ -134,7 +134,7 @@ pub(crate) fn update_os_tree<P: AsRef<Path>>(
                 tempdir.ensure_dir(v, 0o755)?;
                 let dest = tempdir.sub_dir(v)?;
                 mutated += mutate_executables_to(&src, &dest, percentage)
-                    .with_context(|| format!("Replacing binaries in {}", v))?;
+                    .with_context(|| format!("Replacing binaries in {v}"))?;
             }
         }
     }