fix(overlay): overlay use and overlay hide now update config state (#16154)

- fixes #5986
- fixes #7760
- fixes #8856
- fixes #10592
- fixes #11082

# Description
Unconditionally update the config state after each `overlay use` and
`overlay hide`.

The fix looks simple, but only because of the constant improvements and
refactors to the codebase that have taken place over time made it
possible.

Fixing these issue when they were initially filed would have been much
harder.

# User-Facing Changes
Overlays can add hooks, change color_config, update the config in
general.

# Tests + Formatting
No tests added as I still haven't figured out how to simulate the repl
in tests.

# After Submitting
N/A

---------

Co-authored-by: Bahex <17417311+Bahex@users.noreply.github.com>

crates/nu-cmd-lang/src/core_commands/overlay/hide.rs

@@ -96,6 +96,7 @@ impl Command for OverlayHide {
         for (name, val) in env_vars_to_keep {
             stack.add_env_var(name, val);
         }
+        stack.update_config(engine_state)?;
         Ok(PipelineData::empty())
     }
 

crates/nu-cmd-lang/src/core_commands/overlay/use_.rs

@@ -178,6 +178,7 @@ impl Command for OverlayUse {
             }
         } else {
             caller_stack.add_overlay(overlay_name);
+            caller_stack.update_config(engine_state)?;
         }
 
         Ok(PipelineData::empty())

tests/overlays/mod.rs

@@ -918,6 +918,74 @@ fn overlay_use_export_env() {
     assert_eq!(actual_repl.out, "foo");
 }
 
+#[test]
+fn overlay_use_export_env_config_affected() {
+    let inp = &[
+        "mut out = []",
+        "$env.config.filesize.unit = 'metric'",
+        "$out ++= [(20MB | into string)]",
+        "module spam { export-env { $env.config.filesize.unit = 'binary' } }",
+        "overlay use spam",
+        "$out ++= [(20MiB | into string)]",
+        r#"$out | to json --raw"#,
+    ];
+
+    let actual = nu!(&inp.join("; "));
+    let actual_repl = nu!(nu_repl_code(inp));
+
+    assert_eq!(actual.out, r#"["20.0 MB","20.0 MiB"]"#);
+    assert_eq!(actual_repl.out, r#"["20.0 MB","20.0 MiB"]"#);
+}
+
+#[test]
+fn overlay_hide_config_affected() {
+    let inp = &[
+        "mut out = []",
+        "$env.config.filesize.unit = 'metric'",
+        "$out ++= [(20MB | into string)]",
+        "module spam { export-env { $env.config.filesize.unit = 'binary' } }",
+        "overlay use spam",
+        "$out ++= [(20MiB | into string)]",
+        "overlay hide",
+        "$out ++= [(20MB | into string)]",
+        r#"$out | to json --raw"#,
+    ];
+
+    // Can't hide overlay within the same source file
+    // let actual = nu!(&inp.join("; "));
+    let actual_repl = nu!(nu_repl_code(inp));
+
+    // assert_eq!(actual.out, r#"["20.0 MB","20.0 MiB","20.0 MB"]"#);
+    assert_eq!(actual_repl.out, r#"["20.0 MB","20.0 MiB","20.0 MB"]"#);
+}
+
+#[test]
+fn overlay_use_after_hide_config_affected() {
+    let inp = &[
+        "mut out = []",
+        "$env.config.filesize.unit = 'metric'",
+        "$out ++= [(20MB | into string)]",
+        "module spam { export-env { $env.config.filesize.unit = 'binary' } }",
+        "overlay use spam",
+        "$out ++= [(20MiB | into string)]",
+        "overlay hide",
+        "$out ++= [(20MB | into string)]",
+        "overlay use spam",
+        "$out ++= [(20MiB | into string)]",
+        r#"$out | to json --raw"#,
+    ];
+
+    // Can't hide overlay within the same source file
+    // let actual = nu!(&inp.join("; "));
+    let actual_repl = nu!(nu_repl_code(inp));
+
+    // assert_eq!(actual.out, r#"["20.0 MB","20.0 MiB","20.0 MB"]"#);
+    assert_eq!(
+        actual_repl.out,
+        r#"["20.0 MB","20.0 MiB","20.0 MB","20.0 MiB"]"#
+    );
+}
+
 #[test]
 fn overlay_use_export_env_hide() {
     let inp = &[