copy-tracking: add support for diff --git

CHANGELOG.md

@@ -15,7 +15,7 @@ to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 ### New features
 
 * The following diff formats now include information about copies and moves:
-  `--color-words`, `--stat`, `--summary`, `--types`
+  `--color-words`, `--git`, `--stat`, `--summary`, `--types`
 
 * A tilde (`~`) at the start of the path will now be expanded to the user's home
   directory when configuring a `signing.key` for SSH commit signing.

cli/src/commit_templater.rs

@@ -1366,8 +1366,20 @@ fn builtin_tree_diff_methods<'repo>() -> CommitTemplateBuildMethodFnMap<'repo, T
         let template = (self_property, context_property)
             .map(|(diff, context)| {
                 let context = context.unwrap_or(diff_util::DEFAULT_CONTEXT_LINES);
-                diff.into_formatted(move |formatter, store, tree_diff| {
-                    diff_util::show_git_diff(formatter, store, tree_diff, context)
+                // TODO: don't pass separate copies of from_tree/to_tree/matcher
+                let from_tree = diff.from_tree.clone();
+                let to_tree = diff.to_tree.clone();
+                let matcher = diff.matcher.clone();
+                diff.into_formatted(move |formatter, store, _tree_diff| {
+                    diff_util::show_git_diff(
+                        formatter,
+                        store,
+                        &from_tree,
+                        &to_tree,
+                        matcher.as_ref(),
+                        &Default::default(), // TODO: real copy tracking
+                        context,
+                    )
                 })
             })
             .into_template();
@@ -1405,7 +1417,7 @@ fn builtin_tree_diff_methods<'repo>() -> CommitTemplateBuildMethodFnMap<'repo, T
                             &from_tree,
                             &to_tree,
                             matcher.as_ref(),
-                            &Default::default(),
+                            &Default::default(), // TODO: real copy tracking
                         )
                     })
                 })

cli/src/diff_util.rs

@@ -308,9 +308,15 @@ impl<'a> DiffRenderer<'a> {
                     show_names(formatter, tree_diff, path_converter)?;
                 }
                 DiffFormat::Git { context } => {
-                    let no_copy_tracking = Default::default();
-                    let tree_diff = from_tree.diff_stream(to_tree, matcher, &no_copy_tracking);
-                    show_git_diff(formatter, store, tree_diff, *context)?;
+                    show_git_diff(
+                        formatter,
+                        store,
+                        from_tree,
+                        to_tree,
+                        matcher,
+                        copy_records,
+                        *context,
+                    )?;
                 }
                 DiffFormat::ColorWords { context } => {
                     let tree_diff = from_tree.diff_stream(to_tree, matcher, copy_records);
@@ -1098,23 +1104,40 @@ fn show_unified_diff_hunks(
 pub fn show_git_diff(
     formatter: &mut dyn Formatter,
     store: &Store,
-    tree_diff: TreeDiffStream,
+    from_tree: &MergedTree,
+    to_tree: &MergedTree,
+    matcher: &dyn Matcher,
+    copy_records: &CopyRecords,
     num_context_lines: usize,
 ) -> Result<(), DiffRenderError> {
+    let tree_diff = from_tree.diff_stream(to_tree, matcher, copy_records);
     let mut diff_stream = materialized_diff_stream(store, tree_diff);
+    let copied_sources = collect_copied_sources(copy_records, matcher);
+
     async {
         while let Some(MaterializedTreeDiffEntry {
-            source: _, // TODO handle copy tracking
-            target: path,
+            source: left_path,
+            target: right_path,
             value: diff,
         }) = diff_stream.next().await
         {
-            let path_string = path.as_internal_file_string();
+            let left_path_string = left_path.as_internal_file_string();
+            let right_path_string = right_path.as_internal_file_string();
             let (left_value, right_value) = diff?;
-            let left_part = git_diff_part(&path, left_value)?;
-            let right_part = git_diff_part(&path, right_value)?;
+
+            let left_part = git_diff_part(&left_path, left_value)?;
+            let right_part = git_diff_part(&right_path, right_value)?;
+
+            // Skip the "delete" entry when there is a rename.
+            if right_part.mode.is_none() && copied_sources.contains(left_path.as_ref()) {
+                continue;
+            }
+
             formatter.with_label("file_header", |formatter| {
-                writeln!(formatter, "diff --git a/{path_string} b/{path_string}")?;
+                writeln!(
+                    formatter,
+                    "diff --git a/{left_path_string} b/{right_path_string}"
+                )?;
                 let left_hash = &left_part.hash;
                 let right_hash = &right_part.hash;
                 match (left_part.mode, right_part.mode) {
@@ -1127,6 +1150,16 @@ pub fn show_git_diff(
                         writeln!(formatter, "index {left_hash}..{right_hash}")?;
                     }
                     (Some(left_mode), Some(right_mode)) => {
+                        if left_path != right_path {
+                            let operation = if to_tree.path_value(&left_path).unwrap().is_absent() {
+                                "rename"
+                            } else {
+                                "copy"
+                            };
+                            // TODO: include similarity index?
+                            writeln!(formatter, "{operation} from {left_path_string}")?;
+                            writeln!(formatter, "{operation} to {right_path_string}")?;
+                        }
                         if left_mode != right_mode {
                             writeln!(formatter, "old mode {left_mode}")?;
                             writeln!(formatter, "new mode {right_mode}")?;
@@ -1147,11 +1180,11 @@ pub fn show_git_diff(
             }
 
             let left_path = match left_part.mode {
-                Some(_) => format!("a/{path_string}"),
+                Some(_) => format!("a/{left_path_string}"),
                 None => "/dev/null".to_owned(),
             };
             let right_path = match right_part.mode {
-                Some(_) => format!("b/{path_string}"),
+                Some(_) => format!("b/{right_path_string}"),
                 None => "/dev/null".to_owned(),
             };
             if left_part.content.is_binary || right_part.content.is_binary {

cli/tests/test_diff_command.rs

@@ -80,7 +80,7 @@ fn test_diff_basic() {
     FF file2
     "###);
 
-    let stdout = test_env.jj_cmd_success(&repo_path, &["diff", "--git"]);
+    let stdout = test_env.jj_cmd_success(&repo_path, &["diff", "--git", "file1"]);
     insta::assert_snapshot!(stdout, @r###"
     diff --git a/file1 b/file1
     deleted file mode 100644
@@ -89,6 +89,10 @@ fn test_diff_basic() {
     +++ /dev/null
     @@ -1,1 +1,0 @@
     -foo
+    "###);
+
+    let stdout = test_env.jj_cmd_success(&repo_path, &["diff", "--git"]);
+    insta::assert_snapshot!(stdout, @r###"
     diff --git a/file2 b/file2
     index 523a4a9de8..485b56a572 100644
     --- a/file2
@@ -98,24 +102,13 @@ fn test_diff_basic() {
     -baz qux
     +bar
     +baz quux
-    diff --git a/file3 b/file3
-    new file mode 100644
-    index 0000000000..257cc5642c
-    --- /dev/null
-    +++ b/file3
-    @@ -1,0 +1,1 @@
-    +foo
+    diff --git a/file1 b/file3
+    rename from file1
+    rename to file3
     "###);
 
     let stdout = test_env.jj_cmd_success(&repo_path, &["diff", "--git", "--context=0"]);
     insta::assert_snapshot!(stdout, @r###"
-    diff --git a/file1 b/file1
-    deleted file mode 100644
-    index 257cc5642c..0000000000
-    --- a/file1
-    +++ /dev/null
-    @@ -1,1 +1,0 @@
-    -foo
     diff --git a/file2 b/file2
     index 523a4a9de8..485b56a572 100644
     --- a/file2
@@ -124,24 +117,13 @@ fn test_diff_basic() {
     -baz qux
     +bar
     +baz quux
-    diff --git a/file3 b/file3
-    new file mode 100644
-    index 0000000000..257cc5642c
-    --- /dev/null
-    +++ b/file3
-    @@ -1,0 +1,1 @@
-    +foo
+    diff --git a/file1 b/file3
+    rename from file1
+    rename to file3
     "###);
 
     let stdout = test_env.jj_cmd_success(&repo_path, &["diff", "--git", "--color=debug"]);
     insta::assert_snapshot!(stdout, @r###"
-    <<diff file_header::diff --git a/file1 b/file1>>
-    <<diff file_header::deleted file mode 100644>>
-    <<diff file_header::index 257cc5642c..0000000000>>
-    <<diff file_header::--- a/file1>>
-    <<diff file_header::+++ /dev/null>>
-    <<diff hunk_header::@@ -1,1 +1,0 @@>>
-    <<diff removed::->><<diff removed token::foo>>
     <<diff file_header::diff --git a/file2 b/file2>>
     <<diff file_header::index 523a4a9de8..485b56a572 100644>>
     <<diff file_header::--- a/file2>>
@@ -151,26 +133,15 @@ fn test_diff_basic() {
     <<diff removed::-baz >><<diff removed token::qux>><<diff removed::>>
     <<diff added::+>><<diff added token::bar>>
     <<diff added::+baz >><<diff added token::quux>><<diff added::>>
-    <<diff file_header::diff --git a/file3 b/file3>>
-    <<diff file_header::new file mode 100644>>
-    <<diff file_header::index 0000000000..257cc5642c>>
-    <<diff file_header::--- /dev/null>>
-    <<diff file_header::+++ b/file3>>
-    <<diff hunk_header::@@ -1,0 +1,1 @@>>
-    <<diff added::+>><<diff added token::foo>>
+    <<diff file_header::diff --git a/file1 b/file3>>
+    <<diff file_header::rename from file1>>
+    <<diff file_header::rename to file3>>
     "###);
 
     let stdout = test_env.jj_cmd_success(&repo_path, &["diff", "-s", "--git"]);
     insta::assert_snapshot!(stdout, @r###"
     M file2
     R {file1 => file3}
-    diff --git a/file1 b/file1
-    deleted file mode 100644
-    index 257cc5642c..0000000000
-    --- a/file1
-    +++ /dev/null
-    @@ -1,1 +1,0 @@
-    -foo
     diff --git a/file2 b/file2
     index 523a4a9de8..485b56a572 100644
     --- a/file2
@@ -180,13 +151,9 @@ fn test_diff_basic() {
     -baz qux
     +bar
     +baz quux
-    diff --git a/file3 b/file3
-    new file mode 100644
-    index 0000000000..257cc5642c
-    --- /dev/null
-    +++ b/file3
-    @@ -1,0 +1,1 @@
-    +foo
+    diff --git a/file1 b/file3
+    rename from file1
+    rename to file3
     "###);
 
     let stdout = test_env.jj_cmd_success(&repo_path, &["diff", "--stat"]);

cli/tests/test_show_command.rs

@@ -136,13 +136,6 @@ fn test_show_basic() {
 
         (no description set)
 
-    diff --git a/file1 b/file1
-    deleted file mode 100644
-    index 257cc5642c..0000000000
-    --- a/file1
-    +++ /dev/null
-    @@ -1,1 +1,0 @@
-    -foo
     diff --git a/file2 b/file2
     index 523a4a9de8..485b56a572 100644
     --- a/file2
@@ -152,13 +145,9 @@ fn test_show_basic() {
     -baz qux
     +bar
     +baz quux
-    diff --git a/file3 b/file3
-    new file mode 100644
-    index 0000000000..257cc5642c
-    --- /dev/null
-    +++ b/file3
-    @@ -1,0 +1,1 @@
-    +foo
+    diff --git a/file1 b/file3
+    rename from file1
+    rename to file3
     "###);
 
     let stdout = test_env.jj_cmd_success(&repo_path, &["show", "--git", "--context=0"]);
@@ -170,13 +159,6 @@ fn test_show_basic() {
 
         (no description set)
 
-    diff --git a/file1 b/file1
-    deleted file mode 100644
-    index 257cc5642c..0000000000
-    --- a/file1
-    +++ /dev/null
-    @@ -1,1 +1,0 @@
-    -foo
     diff --git a/file2 b/file2
     index 523a4a9de8..485b56a572 100644
     --- a/file2
@@ -185,13 +167,9 @@ fn test_show_basic() {
     -baz qux
     +bar
     +baz quux
-    diff --git a/file3 b/file3
-    new file mode 100644
-    index 0000000000..257cc5642c
-    --- /dev/null
-    +++ b/file3
-    @@ -1,0 +1,1 @@
-    +foo
+    diff --git a/file1 b/file3
+    rename from file1
+    rename to file3
     "###);
 
     let stdout = test_env.jj_cmd_success(&repo_path, &["show", "--git", "--color=debug"]);
@@ -203,13 +181,6 @@ fn test_show_basic() {
 
     <<description placeholder::    (no description set)>>
 
-    <<diff file_header::diff --git a/file1 b/file1>>
-    <<diff file_header::deleted file mode 100644>>
-    <<diff file_header::index 257cc5642c..0000000000>>
-    <<diff file_header::--- a/file1>>
-    <<diff file_header::+++ /dev/null>>
-    <<diff hunk_header::@@ -1,1 +1,0 @@>>
-    <<diff removed::->><<diff removed token::foo>>
     <<diff file_header::diff --git a/file2 b/file2>>
     <<diff file_header::index 523a4a9de8..485b56a572 100644>>
     <<diff file_header::--- a/file2>>
@@ -219,13 +190,9 @@ fn test_show_basic() {
     <<diff removed::-baz >><<diff removed token::qux>><<diff removed::>>
     <<diff added::+>><<diff added token::bar>>
     <<diff added::+baz >><<diff added token::quux>><<diff added::>>
-    <<diff file_header::diff --git a/file3 b/file3>>
-    <<diff file_header::new file mode 100644>>
-    <<diff file_header::index 0000000000..257cc5642c>>
-    <<diff file_header::--- /dev/null>>
-    <<diff file_header::+++ b/file3>>
-    <<diff hunk_header::@@ -1,0 +1,1 @@>>
-    <<diff added::+>><<diff added token::foo>>
+    <<diff file_header::diff --git a/file1 b/file3>>
+    <<diff file_header::rename from file1>>
+    <<diff file_header::rename to file3>>
     "###);
 
     let stdout = test_env.jj_cmd_success(&repo_path, &["show", "-s", "--git"]);
@@ -239,13 +206,6 @@ fn test_show_basic() {
 
     M file2
     R {file1 => file3}
-    diff --git a/file1 b/file1
-    deleted file mode 100644
-    index 257cc5642c..0000000000
-    --- a/file1
-    +++ /dev/null
-    @@ -1,1 +1,0 @@
-    -foo
     diff --git a/file2 b/file2
     index 523a4a9de8..485b56a572 100644
     --- a/file2
@@ -255,13 +215,9 @@ fn test_show_basic() {
     -baz qux
     +bar
     +baz quux
-    diff --git a/file3 b/file3
-    new file mode 100644
-    index 0000000000..257cc5642c
-    --- /dev/null
-    +++ b/file3
-    @@ -1,0 +1,1 @@
-    +foo
+    diff --git a/file1 b/file3
+    rename from file1
+    rename to file3
     "###);
 
     let stdout = test_env.jj_cmd_success(&repo_path, &["show", "--stat"]);