Improve stash view, support applying stash file/hunk/line path

src/default_config.toml

@@ -113,6 +113,7 @@ root.show = ["enter"]
 root.discard = ["K"]
 root.stage = ["s"]
 root.unstage = ["u"]
+root.apply = ["a"]
 root.copy_hash = ["y"]
 
 root.help_menu = ["h", "?"]

src/git/mod.rs

@@ -192,21 +192,110 @@ pub(crate) fn show(repo: &Repository, reference: &str) -> Res<Diff> {
     })
 }
 
-pub(crate) fn stash_show(repo: &Repository, stash_ref: &str) -> Res<Diff> {
-    let text = String::from_utf8_lossy(
-        &Command::new("git")
-            .current_dir(repo.workdir().expect("Bare repos unhandled"))
-            .args(["stash", "show", "-p", stash_ref])
+#[derive(Debug, Clone)]
+pub(crate) struct StashDiffs {
+    pub staged: Diff,
+    pub unstaged: Diff,
+    pub untracked: Option<Diff>,
+}
+
+pub(crate) fn stash_diffs(repo: &Repository, stash_ref: &str) -> Res<StashDiffs> {
+    let dir = repo.workdir().expect("Bare repos unhandled");
+
+    let stash_commit = repo
+        .revparse_single(stash_ref)
+        .map_err(Error::GitShowMeta)?
+        .peel_to_commit()
+        .map_err(Error::GitShowMeta)?;
+
+    let diff = |from: &str, to: &str, paths: &[std::ffi::OsString]| -> Res<Diff> {
+        let mut cmd = Command::new("git");
+        cmd.current_dir(dir);
+        cmd.args(["diff", "--no-ext-diff"]);
+        cmd.args([from, to]);
+        if !paths.is_empty() {
+            cmd.arg("--");
+            cmd.args(paths);
+        }
+
+        let text =
+            String::from_utf8_lossy(&cmd.output().map_err(Error::GitDiff)?.stdout).into_owned();
+
+        Ok(Diff {
+            file_diffs: gitu_diff::Parser::new(&text).parse_diff().unwrap(),
+            diff_type: DiffType::TreeToTree,
+            text,
+        })
+    };
+
+    let show = || -> Res<Diff> {
+        let text = String::from_utf8_lossy(
+            &Command::new("git")
+                .current_dir(dir)
+                .args(["stash", "show", "-p", stash_ref])
+                .output()
+                .map_err(Error::GitShow)?
+                .stdout,
+        )
+        .into_owned();
+
+        Ok(Diff {
+            file_diffs: gitu_diff::Parser::new(&text).parse_diff().unwrap(),
+            diff_type: DiffType::TreeToTree,
+            text,
+        })
+    };
+
+    if stash_commit.parent_count() < 2 {
+        let empty = Diff {
+            text: String::new(),
+            diff_type: DiffType::TreeToTree,
+            file_diffs: vec![],
+        };
+        return Ok(StashDiffs {
+            staged: empty,
+            unstaged: show()?,
+            untracked: None,
+        });
+    }
+
+    let base_ref = format!("{stash_ref}^");
+    let index_ref = format!("{stash_ref}^2");
+
+    let staged = diff(&base_ref, &index_ref, &[])?;
+    let unstaged = diff(&index_ref, stash_ref, &[])?;
+
+    let untracked = if stash_commit.parent_count() >= 3 {
+        let untracked_ref = format!("{stash_ref}^3");
+        let paths_out = Command::new("git")
+            .current_dir(dir)
+            .args([
+                "ls-tree",
+                "-z",
+                "--name-only",
+                "-r",
+                "--full-tree",
+                &untracked_ref,
+            ])
             .output()
             .map_err(Error::GitShow)?
-            .stdout,
-    )
-    .into_owned();
+            .stdout;
 
-    Ok(Diff {
-        file_diffs: gitu_diff::Parser::new(&text).parse_diff().unwrap(),
-        diff_type: DiffType::TreeToTree,
-        text,
+        let paths = paths_out
+            .split(|b| *b == b'\0')
+            .filter(|p| !p.is_empty())
+            .map(|p| std::ffi::OsString::from(String::from_utf8_lossy(p).into_owned()))
+            .collect::<Vec<_>>();
+
+        Some(diff(&base_ref, &untracked_ref, &paths)?)
+    } else {
+        None
+    };
+
+    Ok(StashDiffs {
+        staged,
+        unstaged,
+        untracked,
     })
 }
 

src/item_data.rs

@@ -87,4 +87,8 @@ pub(crate) enum SectionHeader {
     Stashes,
     RecentCommits,
     Commit(String),
+    StashRef(String),
+    StagedChanges(usize),
+    UnstagedChanges(usize),
+    UntrackedFiles(usize),
 }

src/items.rs

@@ -152,6 +152,10 @@ impl Item {
                     SectionHeader::Stashes => "Stashes".to_string(),
                     SectionHeader::RecentCommits => "Recent commits".to_string(),
                     SectionHeader::Commit(oid) => format!("commit {oid}"),
+                    SectionHeader::StashRef(stash_ref) => stash_ref,
+                    SectionHeader::StagedChanges(count) => format!("Staged changes ({count})"),
+                    SectionHeader::UnstagedChanges(count) => format!("Unstaged changes ({count})"),
+                    SectionHeader::UntrackedFiles(count) => format!("Untracked files ({count})"),
                 };
 
                 Line::styled(content, &config.style.section_header)

src/ops/apply.rs

@@ -0,0 +1,79 @@
+use super::OpTrait;
+use crate::{
+    Action,
+    app::{App, State},
+    git::diff::{Diff, PatchMode},
+    item_data::ItemData,
+    term::Term,
+};
+use std::{process::Command, rc::Rc};
+
+pub(crate) struct Apply;
+impl OpTrait for Apply {
+    fn get_action(&self, target: &ItemData) -> Option<Action> {
+        let action = match target {
+            ItemData::Stash { stash_ref, .. } => apply_stash(stash_ref.clone()),
+            ItemData::Delta { diff, file_i } => apply_patch(diff.format_file_patch(*file_i)),
+            ItemData::Hunk {
+                diff,
+                file_i,
+                hunk_i,
+            } => apply_patch(diff.format_hunk_patch(*file_i, *hunk_i)),
+            ItemData::HunkLine {
+                diff,
+                file_i,
+                hunk_i,
+                line_i,
+                ..
+            } => apply_line(diff, *file_i, *hunk_i, *line_i),
+            _ => return None,
+        };
+
+        Some(action)
+    }
+
+    fn is_target_op(&self) -> bool {
+        true
+    }
+
+    fn display(&self, _state: &State) -> String {
+        "Apply".into()
+    }
+}
+
+fn apply_stash(stash_ref: String) -> Action {
+    Rc::new(move |app: &mut App, term: &mut Term| {
+        let mut cmd = Command::new("git");
+        cmd.args(["stash", "apply", "-q"]);
+        cmd.arg(&stash_ref);
+
+        app.close_menu();
+        app.run_cmd(term, &[], cmd)
+    })
+}
+
+fn apply_line(diff: &Rc<Diff>, file_i: usize, hunk_i: usize, line_i: usize) -> Action {
+    let patch = diff
+        .format_line_patch(file_i, hunk_i, line_i..(line_i + 1), PatchMode::Normal)
+        .into_bytes();
+
+    Rc::new(move |app: &mut App, term: &mut Term| {
+        let mut cmd = Command::new("git");
+        cmd.args(["apply", "--recount"]);
+
+        app.close_menu();
+        app.run_cmd(term, &patch, cmd)
+    })
+}
+
+fn apply_patch(patch: String) -> Action {
+    let patch = patch.into_bytes();
+
+    Rc::new(move |app: &mut App, term: &mut Term| {
+        let mut cmd = Command::new("git");
+        cmd.arg("apply");
+
+        app.close_menu();
+        app.run_cmd(term, &patch, cmd)
+    })
+}

src/ops/mod.rs

@@ -9,6 +9,7 @@ use crate::{
 };
 use std::{fmt::Display, rc::Rc};
 
+pub(crate) mod apply;
 pub(crate) mod branch;
 pub(crate) mod commit;
 pub(crate) mod copy_hash;
@@ -100,6 +101,7 @@ pub(crate) enum Op {
     Unstage,
     Show,
     Discard,
+    Apply,
     CopyHash,
 
     ToggleSection,
@@ -187,6 +189,7 @@ impl Op {
             Op::Show => Box::new(show::Show),
             Op::Stage => Box::new(stage::Stage),
             Op::Unstage => Box::new(unstage::Unstage),
+            Op::Apply => Box::new(apply::Apply),
             Op::CopyHash => Box::new(copy_hash::CopyHash),
 
             Op::AddRemote => Box::new(remote::AddRemote),

src/screen/show_stash.rs

@@ -23,25 +23,70 @@ pub(crate) fn create(
         size,
         Box::new(move || {
             let commit = git::show_summary(repo.as_ref(), &stash_ref)?;
-            let show = git::stash_show(repo.as_ref(), &stash_ref)?;
             let details = commit.details.lines();
 
-            Ok(iter::once(Item {
-                id: hash(["stash_section", &commit.hash]),
+            let git::StashDiffs {
+                staged,
+                unstaged,
+                untracked,
+            } = git::stash_diffs(repo.as_ref(), &stash_ref)?;
+
+            let mut out: Vec<Item> = Vec::new();
+            out.extend(iter::once(Item {
+                id: hash(["stash_section", &stash_ref]),
                 depth: 0,
-                data: ItemData::Header(SectionHeader::Commit(commit.hash.clone())),
+                data: ItemData::Header(SectionHeader::StashRef(stash_ref.clone())),
                 ..Default::default()
-            })
-            .chain(details.into_iter().map(|line| Item {
-                id: hash(["stash", &commit.hash]),
+            }));
+            out.extend(details.into_iter().map(|line| Item {
+                id: hash(["stash", &stash_ref]),
                 depth: 1,
                 unselectable: true,
                 data: ItemData::Raw(line.to_string()),
                 ..Default::default()
-            }))
-            .chain([items::blank_line()])
-            .chain(items::create_diff_items(&Rc::new(show), 0, false))
-            .collect())
+            }));
+
+            let push_diff_section = |out: &mut Vec<Item>, header: SectionHeader, diff| {
+                let diff = Rc::new(diff);
+                out.extend([
+                    items::blank_line(),
+                    Item {
+                        id: hash(["stash_diff_section", &commit.hash, &format!("{header:?}")]),
+                        depth: 0,
+                        data: ItemData::Header(header),
+                        ..Default::default()
+                    },
+                ]);
+                out.extend(items::create_diff_items(&diff, 1, false));
+            };
+
+            if !staged.file_diffs.is_empty() {
+                push_diff_section(
+                    &mut out,
+                    SectionHeader::StagedChanges(staged.file_diffs.len()),
+                    staged,
+                );
+            }
+
+            if !unstaged.file_diffs.is_empty() {
+                push_diff_section(
+                    &mut out,
+                    SectionHeader::UnstagedChanges(unstaged.file_diffs.len()),
+                    unstaged,
+                );
+            }
+
+            if let Some(untracked) = untracked
+                && !untracked.file_diffs.is_empty()
+            {
+                push_diff_section(
+                    &mut out,
+                    SectionHeader::UntrackedFiles(untracked.file_diffs.len()),
+                    untracked,
+                );
+            }
+
+            Ok(out)
         }),
     )
 }

src/tests/mod.rs

@@ -170,11 +170,30 @@ fn show() {
 fn show_stash() {
     let ctx = setup_clone!();
 
-    fs::write(ctx.dir.join("file1.txt"), "content").unwrap();
-    run(&ctx.dir, &["git", "add", "file1.txt"]);
-    // Unstaged changes to "file1.txt"
-    fs::write(ctx.dir.join("file1.txt"), "content\nmodified content").unwrap();
-    run(&ctx.dir, &["git", "stash", "save", "firststash"]);
+    // Unstaged changes should be shown as a diff against a tracked file.
+    commit(&ctx.dir, "unstaged.txt", "");
+
+    // Staged changes
+    fs::write(ctx.dir.join("staged.txt"), "staged\n").unwrap();
+    run(&ctx.dir, &["git", "add", "staged.txt"]);
+
+    // Unstaged changes
+    fs::write(ctx.dir.join("unstaged.txt"), "unstaged\n").unwrap();
+
+    // Untracked changes
+    fs::write(ctx.dir.join("untracked.txt"), "untracked\n").unwrap();
+
+    run(
+        &ctx.dir,
+        &[
+            "git",
+            "stash",
+            "push",
+            "--include-untracked",
+            "--message",
+            "firststash",
+        ],
+    );
 
     snapshot!(ctx, "jj<enter>");
 }
@@ -285,7 +304,8 @@ fn hide_untracked() {
 
     let mut app = ctx.init_app();
     let mut config = app.state.repo.config().unwrap();
-    config.set_str("status.showUntrackedFiles", "off").unwrap();
+    // Git expects "no|normal|all" here; "off" can error on some versions and break `git status`.
+    config.set_str("status.showUntrackedFiles", "no").unwrap();
 
     ctx.update(&mut app, keys("g"));
     insta::assert_snapshot!(ctx.redact_buffer());