From 3280d75ff479fba08c581b5843d3ba5e1e35f4a2 Mon Sep 17 00:00:00 2001
From: Martin von Zweigbergk <martinvonz@google.com>
Date: Sat, 26 Dec 2020 10:34:58 -0800
Subject: [PATCH] diff_edit: mark "before" directory readonly to clarify to
 user

Changes to the "before" side of the diff will have no effect, so let's
clarify that by marking it readonly. At least Meld checks the
permissions and shows in the UI that the left side is readonly.
---
 src/diff_edit.rs | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/src/diff_edit.rs b/src/diff_edit.rs
index 77e9f6a61..2b284e657 100644
--- a/src/diff_edit.rs
+++ b/src/diff_edit.rs
@@ -19,7 +19,7 @@ use jj_lib::tree::Tree;
 use jj_lib::tree_builder::TreeBuilder;
 use jj_lib::trees::merge_trees;
 use jj_lib::working_copy::{CheckoutError, TreeState};
-use std::path::PathBuf;
+use std::path::{Path, PathBuf};
 use std::process::Command;
 use std::sync::Arc;
 use tempfile::tempdir;
@@ -80,6 +80,17 @@ fn check_out(
     Ok(tree_state)
 }
 
+fn set_readonly_recursively(path: &Path) {
+    if path.is_dir() {
+        for entry in path.read_dir().unwrap() {
+            set_readonly_recursively(&entry.unwrap().path());
+        }
+    }
+    let mut perms = std::fs::metadata(path).unwrap().permissions();
+    perms.set_readonly(true);
+    std::fs::set_permissions(path, perms).unwrap();
+}
+
 pub fn edit_diff(left_tree: &Tree, right_tree: &Tree) -> Result<TreeId, DiffEditError> {
     // First create partial Trees of only the subset of the left and right trees
     // that affect files changed between them.
@@ -112,7 +123,7 @@ pub fn edit_diff(left_tree: &Tree, right_tree: &Tree) -> Result<TreeId, DiffEdit
         left_state_dir,
         left_partial_tree_id,
     )?;
-    // TODO: mark left dir readonly
+    set_readonly_recursively(&left_wc_dir);
     let mut right_tree_state = check_out(
         store.clone(),
         right_wc_dir.clone(),