662 submodule diffs (#699)

4 files changed, 119 insertions, 5 deletions

diff --git a/etc/examples/662-submodules b/etc/examples/662-submodules
new file mode 100755
index 00000000..1f4a5189
--- /dev/null
+++ b/etc/examples/662-submodules
@@ -0,0 +1,45 @@
+#!/bin/bash
+REPO_ROOT=/tmp/submodule-diff-example
+REPO_DATE_FMT=%H:%M:%S.%N
+mkdir ${REPO_ROOT} && git -C ${REPO_ROOT} init && cd ${REPO_ROOT}
+date +${REPO_DATE_FMT} >> baserepo && git add baserepo && git commit -m "Base repo commit 1"
+
+for sub in A B C; do
+    git init submodule${sub}
+    for iter in $(seq 1 4); do
+        date +${REPO_DATE_FMT} >> submodule${sub}/subcontent
+        git -C submodule${sub} add subcontent && git -C submodule${sub} commit -m "Submodule ${sub} initial commit $iter"
+    done
+    # Add initial submodule, message of "Submodule submoduleX 0000000...xxxxxxx (new submodule)", no individual commits
+    git submodule add ../bogus-url-${sub} submodule${sub} && \
+        git commit -m "Add submodule${sub}" # the diff handling for this is correct in delta
+
+    # Create additional submodule commits
+    for iter in $(seq 1 2); do
+        date +${REPO_DATE_FMT} >> submodule${sub}/subcontent
+        git -C submodule${sub} add subcontent && git -C submodule${sub} commit -m "Submodule ${sub} extra change ${iter}"
+    done
+    git add submodule${sub} && git commit -m "Update submodule${sub}"
+done
+
+git -C submoduleA reset --hard HEAD~4
+git -C submoduleC reset --hard HEAD~2
+
+for sub in B C; do
+    for iter in $(seq 1 3); do
+        date +${REPO_DATE_FMT} >> submodule${sub}/subcontent
+        git -C submodule${sub} add subcontent && git -C submodule${sub} commit -m "Submodule ${sub} stage change ${iter}"
+    done
+done
+
+# Add all submodule updates in single commit to test multiple submodule updates in single commit
+git add submodule[A-C] && git commit -m "Update all submodules"
+
+# submoduleA end state is only removed commits
+# submoduleB end state is only added commits
+# submoduleC is a mixture of removed and added commits (e.g. different branch)
+
+# Manual, inspect superproject history via:
+#    "git -c diff.submodule=short log -p | delta --no-gitconfig"
+#    "git -c diff.submodule=log log -p | delta --no-gitconfig"
+#    "git -c diff.submodule=diff log -p | delta --no-gitconfig"
diff --git a/src/config.rs b/src/config.rs
index b0a8cb3c..acf7d0c9 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -100,6 +100,7 @@ impl Config {
             State::CommitMeta => &self.commit_style,
             State::FileMeta => &self.file_style,
             State::HunkHeader => &self.hunk_header_style,
+            State::Submodule => &self.file_style,
             _ => delta_unreachable("Unreachable code reached in get_style."),
         }
     }
diff --git a/src/delta.rs b/src/delta.rs
index e1770b7e..c42ba9f1 100644
--- a/src/delta.rs
+++ b/src/delta.rs
@@ -24,6 +24,7 @@ pub enum State {
     HunkZero, // In hunk; unchanged line
     HunkMinus(Option<String>), // In hunk; removed line (raw_line)
     HunkPlus(Option<String>), // In hunk; added line (raw_line)
+    Submodule,
     Unknown,
 }
 
@@ -140,10 +141,11 @@ impl<'a> StateMachine<'a> {
             } else if line.starts_with("@@") {
                 self.handle_hunk_header_line()?
             } else if self.source == Source::DiffUnified && line.starts_with("Only in ")
-                || line.starts_with("Submodule ")
                 || line.starts_with("Binary files ")
             {
-                self.handle_additional_file_meta_cases()?
+                self.handle_additional_cases(State::FileMeta)?
+            } else if line.starts_with("Submodule ") {
+                self.handle_additional_cases(State::Submodule)?
             } else if self.state.is_in_hunk() {
                 // A true hunk line should start with one of: '+', '-', ' '. However, handle_hunk_line
                 // handles all lines until the state transitions away from the hunk states.
@@ -381,10 +383,10 @@ impl<'a> StateMachine<'a> {
         _write_generic_file_meta_header_line(&line, &line, &mut self.painter, self.config)
     }
 
-    fn handle_additional_file_meta_cases(&mut self) -> std::io::Result<bool> {
+    fn handle_additional_cases(&mut self, to_state: State) -> std::io::Result<bool> {
         let mut handled_line = false;
 
-        // Additional FileMeta cases:
+        // Additional cases:
         //
         // 1. When comparing directories with diff -u, if filenames match between the
         //    directories, the files themselves will be compared. However, if an equivalent
@@ -398,7 +400,7 @@ impl<'a> StateMachine<'a> {
         // proposal for more robust parsing logic.
 
         self.painter.paint_buffered_minus_and_plus_lines();
-        self.state = State::FileMeta;
+        self.state = to_state;
         if self.should_handle() {
             self.painter.emit()?;
             _write_generic_file_meta_header_line(
diff --git a/src/tests/test_example_diffs.rs b/src/tests/test_example_diffs.rs
index 3f28d200..3b249eff 100644
--- a/src/tests/test_example_diffs.rs
+++ b/src/tests/test_example_diffs.rs
@@ -201,6 +201,16 @@ mod tests {
     }
 
     #[test]
+    fn test_submodule_diff_log() {
+        // See etc/examples/662-submodules
+        // diff.submodule = log
+        let config = integration_test_utils::make_config_from_args(&["--width", "49"]);
+        let output = integration_test_utils::run_delta(SUBMODULE_DIFF_LOG, &config);
+        let output = strip_ansi_codes(&output);
+        assert_eq!(output, SUBMODULE_DIFF_LOG_EXPECTED_OUTPUT);
+    }
+
+    #[test]
     fn test_submodule_contains_untracked_content() {
         let config = integration_test_utils::make_config_from_args(&[]);
         let output =
@@ -1902,6 +1912,62 @@ This is a regular file that contains:
 +Some text with a plus
 ";
 
+    // See etc/examples/662-submodules
+    // diff.submodule = log
+    const SUBMODULE_DIFF_LOG: &str = "\
+commit ccb444baa861fdcb14d411b471a74614ed28776d
+Author: Dan Davison <dandavison7@gmail.com>
+Date:   Sat Aug 21 18:56:34 2021 -0700
+
+    Update all submodules
+
+Submodule submoduleA f4f55af..310b551 (rewind):
+  < Submodule A extra change 2
+  < Submodule A extra change 1
+  < Submodule A initial commit 4
+  < Submodule A initial commit 3
+Submodule submoduleB 0ffa700..0c8b00d:
+  > Submodule B stage change 3
+  > Submodule B stage change 2
+  > Submodule B stage change 1
+Submodule submoduleC 9f3b744...e04f848:
+  > Submodule C stage change 3
+  > Submodule C stage change 2
+  < Submodule C extra change 2
+  > Submodule C stage change 1
+  < Submodule C extra change 1
+";
+
+    const SUBMODULE_DIFF_LOG_EXPECTED_OUTPUT: &str = "\
+commit ccb444baa861fdcb14d411b471a74614ed28776d
+Author: Dan Davison <dandavison7@gmail.com>
+Date:   Sat Aug 21 18:56:34 2021 -0700
+
+    Update all submodules
+
+
+Submodule submoduleA f4f55af..310b551 (rewind):
+─────────────────────────────────────────────────
+  < Submodule A extra change 2
+  < Submodule A extra change 1
+  < Submodule A initial commit 4
+  < Submodule A initial commit 3
+
+Submodule submoduleB 0ffa700..0c8b00d:
+─────────────────────────────────────────────────
+  > Submodule B stage change 3
+  > Submodule B stage change 2
+  > Submodule B stage change 1
+
+Submodule submoduleC 9f3b744...e04f848:
+─────────────────────────────────────────────────
+  > Submodule C stage change 3
+  > Submodule C stage change 2
+  < Submodule C extra change 2
+  > Submodule C stage change 1
+  < Submodule C extra change 1
+";
+
     const SUBMODULE_CONTAINS_UNTRACKED_CONTENT_INPUT: &str = "\
 --- a
 +++ b