feat(smartlog): add --reverse option

git-branchless-lib/src/core/effects.rs

@@ -567,6 +567,15 @@ impl Effects {
         }
     }
 
+    /// Apply transformations to the returned `Effects` to support emitting
+    /// graphical output in the opposite of its usual order.
+    pub fn reverse_order(&self, reverse: bool) -> Self {
+        Self {
+            glyphs: self.glyphs.clone().reverse_order(reverse),
+            ..self.clone()
+        }
+    }
+
     /// Start reporting progress for the specified operation type.
     ///
     /// A progress spinner is shown until the returned `ProgressHandle` is

git-branchless-lib/src/core/formatting.rs

@@ -218,6 +218,15 @@ impl Glyphs {
         }
     }
 
+    /// Return a `Glyphs` object suitable for rendering graphs in the reverse of
+    /// their usual order.
+    pub fn reverse_order(mut self, reverse: bool) -> Self {
+        if reverse {
+            std::mem::swap(&mut self.split, &mut self.merge);
+        }
+        self
+    }
+
     /// Write the provided string to `out`, using ANSI escape codes as necessary to
     /// style it.
     ///

git-branchless-opts/src/lib.rs

@@ -279,6 +279,11 @@ pub struct SmartlogArgs {
     #[clap(value_parser)]
     pub revset: Option<Revset>,
 
+    /// Print the smartlog in the opposite of the usual order, with the latest
+    /// commits first.
+    #[clap(long)]
+    pub reverse: bool,
+
     /// Options for resolving revset expressions.
     #[clap(flatten)]
     pub resolve_revset_options: ResolveRevsetOptions,

git-branchless-smartlog/src/lib.rs

@@ -749,6 +749,10 @@ mod render {
 
         /// The options to use when resolving the revset.
         pub resolve_revset_options: ResolveRevsetOptions,
+
+        /// Reverse the ordering of items in the smartlog output, list the most
+        /// recent commits first.
+        pub reverse: bool,
     }
 
     impl Default for SmartlogOptions {
@@ -757,6 +761,7 @@ mod render {
                 event_id: Default::default(),
                 revset: Revset::default_smartlog_revset(),
                 resolve_revset_options: Default::default(),
+                reverse: false,
             }
         }
     }
@@ -771,9 +776,10 @@ pub fn smartlog(
 ) -> eyre::Result<ExitCode> {
     let SmartlogOptions {
         event_id,
-        revset,
-        resolve_revset_options,
-    } = options;
+        ref revset,
+        ref resolve_revset_options,
+        reverse,
+    } = *options;
 
     let repo = Repo::from_dir(&git_run_info.working_directory)?;
     let head_info = repo.get_head_info()?;
@@ -786,8 +792,8 @@ pub fn smartlog(
             None => (repo.get_references_snapshot()?, default_cursor),
             Some(event_id) => {
                 let event_cursor = match event_id.cmp(&0) {
-                    Ordering::Less => event_replayer.advance_cursor(default_cursor, *event_id),
-                    Ordering::Equal | Ordering::Greater => event_replayer.make_cursor(*event_id),
+                    Ordering::Less => event_replayer.advance_cursor(default_cursor, event_id),
+                    Ordering::Equal | Ordering::Greater => event_replayer.make_cursor(event_id),
                 };
                 let references_snapshot =
                     event_replayer.get_references_snapshot(&repo, event_cursor)?;
@@ -829,8 +835,8 @@ pub fn smartlog(
         &commits,
     )?;
 
-    let lines = render_graph(
-        effects,
+    let mut lines = render_graph(
+        &effects.reverse_order(reverse),
         &repo,
         &dag,
         &graph,
@@ -851,8 +857,13 @@ pub fn smartlog(
             &mut DifferentialRevisionDescriptor::new(&repo, &Redactor::Disabled)?,
             &mut CommitMessageDescriptor::new(&Redactor::Disabled)?,
         ],
-    )?;
-    for line in lines {
+    )?
+    .into_iter();
+    while let Some(line) = if reverse {
+        lines.next_back()
+    } else {
+        lines.next()
+    } {
         writeln!(
             effects.get_output_stream(),
             "{}",
@@ -912,6 +923,7 @@ pub fn command_main(ctx: CommandContext, args: SmartlogArgs) -> eyre::Result<Exi
         event_id,
         revset,
         resolve_revset_options,
+        reverse,
     } = args;
 
     smartlog(
@@ -921,6 +933,7 @@ pub fn command_main(ctx: CommandContext, args: SmartlogArgs) -> eyre::Result<Exi
             event_id,
             revset: revset.unwrap_or_else(Revset::default_smartlog_revset),
             resolve_revset_options,
+            reverse,
         },
     )
 }

git-branchless-smartlog/tests/test_smartlog.rs

@@ -178,6 +178,43 @@ fn test_merge_commit() -> eyre::Result<()> {
     Ok(())
 }
 
+#[test]
+fn test_merge_commit_reverse_order() -> eyre::Result<()> {
+    let git = make_git()?;
+
+    git.init_repo()?;
+    git.run(&["checkout", "-b", "test1", "master"])?;
+    git.commit_file("test1", 1)?;
+    git.run(&["checkout", "-b", "test2and3", "master"])?;
+    git.commit_file("test2", 2)?;
+    git.commit_file("test3", 3)?;
+    git.run_with_options(
+        &["merge", "test1"],
+        &GitRunOptions {
+            time: 4,
+            ..Default::default()
+        },
+    )?;
+
+    let (stdout, _) = git.branchless("smartlog", &["--reverse"])?;
+    insta::assert_snapshot!(stdout, @r###"
+    @ fa4e4e1 (> test2and3) Merge branch 'test1' into test2and3
+    |\
+    | & (merge) 62fc20d (test1) create test1.txt
+    |
+    o 0206717 create test3.txt
+    |
+    o fe65c1f create test2.txt
+    |
+    | & (merge) fa4e4e1 (> test2and3) Merge branch 'test1' into test2and3
+    | o 62fc20d (test1) create test1.txt
+    |/
+    O f777ecc (master) create initial.txt
+    "###);
+
+    Ok(())
+}
+
 #[test]
 fn test_rebase_conflict() -> eyre::Result<()> {
     let git = make_git()?;
@@ -462,6 +499,39 @@ fn test_smartlog_hint_abandoned_except_current_commit() -> eyre::Result<()> {
     Ok(())
 }
 
+/// When --reverse is specified hints still appear at the end of output
+#[test]
+fn test_smartlog_hint_abandoned_reverse_order() -> eyre::Result<()> {
+    let git = make_git()?;
+
+    if !git.supports_reference_transactions()? {
+        return Ok(());
+    }
+    git.init_repo()?;
+
+    git.detach_head()?;
+    git.commit_file("test1", 1)?;
+    git.commit_file("test2", 2)?;
+    git.run(&["checkout", "HEAD^"])?;
+    git.run(&["commit", "--amend", "-m", "amended test1"])?;
+
+    let (stdout, _) = git.branchless("smartlog", &["--reverse"])?;
+    insta::assert_snapshot!(stdout, @r###"
+    o 96d1c37 create test2.txt
+    |
+    x 62fc20d (rewritten as ae94dc2a) create test1.txt
+    |
+    | @ ae94dc2 amended test1
+    |/
+    O f777ecc (master) create initial.txt
+    hint: there is 1 abandoned commit in your commit graph
+    hint: to fix this, run: git restack
+    hint: disable this hint by running: git config --global branchless.hint.smartlogFixAbandoned false
+    "###);
+
+    Ok(())
+}
+
 #[test]
 fn test_smartlog_sparse() -> eyre::Result<()> {
     let git = make_git()?;

git-branchless/tests/test_init.rs

@@ -316,9 +316,9 @@ fn test_main_branch_not_found_error_message() -> eyre::Result<()> {
 
        0: branchless::core::eventlog::from_event_log_db with effects=<Output fancy=false> repo=<Git repository at: "<repo-path>/.git/"> event_log_db=<EventLogDb>
           at some/file/path.rs:123
-       1: git_branchless_smartlog::smartlog with effects=<Output fancy=false> git_run_info=<GitRunInfo path_to_git="<git-executable>" working_directory="<repo-path>" env=not shown> options=SmartlogOptions { event_id: None, revset: Revset("((draft() | branches() | @) % main()) | branches() | @"), resolve_revset_options: ResolveRevsetOptions { show_hidden_commits: false } }
+       1: git_branchless_smartlog::smartlog with effects=<Output fancy=false> git_run_info=<GitRunInfo path_to_git="<git-executable>" working_directory="<repo-path>" env=not shown> options=SmartlogOptions { event_id: None, revset: Revset("((draft() | branches() | @) % main()) | branches() | @"), resolve_revset_options: ResolveRevsetOptions { show_hidden_commits: false }, reverse: false }
           at some/file/path.rs:123
-       2: git_branchless_smartlog::command_main with ctx=CommandContext { effects: <Output fancy=false>, git_run_info: <GitRunInfo path_to_git="<git-executable>" working_directory="<repo-path>" env=not shown> } args=SmartlogArgs { event_id: None, revset: None, resolve_revset_options: ResolveRevsetOptions { show_hidden_commits: false } }
+       2: git_branchless_smartlog::command_main with ctx=CommandContext { effects: <Output fancy=false>, git_run_info: <GitRunInfo path_to_git="<git-executable>" working_directory="<repo-path>" env=not shown> } args=SmartlogArgs { event_id: None, revset: None, reverse: false, resolve_revset_options: ResolveRevsetOptions { show_hidden_commits: false } }
           at some/file/path.rs:123
 
     Suggestion: