[app-server] feat: add old_content and new_content to FileChange update patches

codex-rs/apply-patch/src/lib.rs

@@ -194,6 +194,8 @@ pub enum ApplyPatchFileChange {
         move_path: Option<PathBuf>,
         /// new_content that will result after the unified_diff is applied.
         new_content: String,
+        /// original content before the diff was applied.
+        old_content: String,
     },
 }
 
@@ -329,6 +331,7 @@ pub fn maybe_parse_apply_patch_verified(argv: &[String], cwd: &Path) -> MaybeApp
                         let ApplyPatchFileUpdate {
                             unified_diff,
                             content: contents,
+                            old_content,
                         } = match unified_diff_from_chunks(&path, &chunks) {
                             Ok(diff) => diff,
                             Err(e) => {
@@ -341,6 +344,7 @@ pub fn maybe_parse_apply_patch_verified(argv: &[String], cwd: &Path) -> MaybeApp
                                 unified_diff,
                                 move_path: move_path.map(|p| effective_cwd.join(p)),
                                 new_content: contents,
+                                old_content,
                             },
                         );
                     }
@@ -846,6 +850,7 @@ fn apply_replacements(
 pub struct ApplyPatchFileUpdate {
     unified_diff: String,
     content: String,
+    old_content: String,
 }
 
 pub fn unified_diff_from_chunks(
@@ -869,6 +874,7 @@ pub fn unified_diff_from_chunks_with_context(
     Ok(ApplyPatchFileUpdate {
         unified_diff,
         content: new_contents,
+        old_content: original_contents,
     })
 }
 
@@ -1467,6 +1473,7 @@ PATCH"#,
         let expected = ApplyPatchFileUpdate {
             unified_diff: expected_diff.to_string(),
             content: "foo\nBAR\nbaz\nQUX\n".to_string(),
+            old_content: "foo\nbar\nbaz\nqux\n".to_string(),
         };
         assert_eq!(expected, diff);
     }
@@ -1503,6 +1510,7 @@ PATCH"#,
         let expected = ApplyPatchFileUpdate {
             unified_diff: expected_diff.to_string(),
             content: "FOO\nbar\nbaz\n".to_string(),
+            old_content: "foo\nbar\nbaz\n".to_string(),
         };
         assert_eq!(expected, diff);
     }
@@ -1540,6 +1548,7 @@ PATCH"#,
         let expected = ApplyPatchFileUpdate {
             unified_diff: expected_diff.to_string(),
             content: "foo\nbar\nBAZ\n".to_string(),
+            old_content: "foo\nbar\nbaz\n".to_string(),
         };
         assert_eq!(expected, diff);
     }
@@ -1574,6 +1583,7 @@ PATCH"#,
         let expected = ApplyPatchFileUpdate {
             unified_diff: expected_diff.to_string(),
             content: "foo\nbar\nbaz\nquux\n".to_string(),
+            old_content: "foo\nbar\nbaz\n".to_string(),
         };
         assert_eq!(expected, diff);
     }
@@ -1629,6 +1639,7 @@ PATCH"#,
         let expected = ApplyPatchFileUpdate {
             unified_diff: expected_diff.to_string(),
             content: "a\nB\nc\nd\nE\nf\ng\n".to_string(),
+            old_content: "a\nb\nc\nd\ne\nf\n".to_string(),
         };
 
         assert_eq!(expected, diff);
@@ -1688,6 +1699,7 @@ g
                         .to_string(),
                         move_path: None,
                         new_content: "updated session directory content\n".to_string(),
+                        old_content: "session directory content\n".to_string(),
                     },
                 )]),
                 patch: argv[1].clone(),