feat: add --strict option to enforce strict checking of configuration.

src/plumbing/main.rs

@@ -71,7 +71,7 @@ pub fn main() -> Result<()> {
         let config = config.clone();
         move |mode: Mode| -> Result<git::Repository> {
             let mut mapping: git::sec::trust::Mapping<git::open::Options> = Default::default();
-            let strict_toggle = matches!(mode, Mode::Strict | Mode::StrictWithGitInstallConfig);
+            let strict_toggle = matches!(mode, Mode::Strict | Mode::StrictWithGitInstallConfig) || args.strict;
             mapping.full = mapping.full.strict_config(strict_toggle);
             mapping.reduced = mapping.reduced.strict_config(strict_toggle);
             let git_installation = matches!(

src/plumbing/options/mod.rs

@@ -35,6 +35,14 @@ pub struct Args {
     #[clap(long, conflicts_with("verbose"))]
     pub progress: bool,
 
+    /// Don't default malformed configuration flags, but show an error instead.
+    ///
+    /// Note that some subcommands use strict mode by default.
+    // TODO: needs a 'lenient' mutually exclusive counterpart. Opens the gate to auto-verbose some commands, and add --no-verbose
+    //       for these.
+    #[clap(long, short = 's')]
+    pub strict: bool,
+
     /// The progress TUI will stay up even though the work is already completed.
     ///
     /// Use this to be able to read progress messages or additional information visible in the TUI log pane.