feat: Support arbitrary references as merge-base targets

CHANGELOG.md

@@ -1,47 +1,50 @@
 # Unreleased
 
+- Support arbitrary refs (i.e. tags like `v0.1.0` and full refspecs
+  like `ref/pull/ID`) as the merge-base selector.
+
 # Version 0.2.6
 
-* Fix and improve the experience of working with a main-only workflow.
+- Fix and improve the experience of working with a main-only workflow.
   - Provide a tailored error message if your current branch is the selected upstream branch
   - Work correctly with explicitly-defined remote upstream branches.
 
 # Version 0.2.5
 
-* Correctly find git repos in parent dirs of CWD
-* Enable experimental github release attestations in cargo-dist
+- Correctly find git repos in parent dirs of CWD
+- Enable experimental github release attestations in cargo-dist
 
 # Version 0.2.4
 
-* Retarget multiple branches pointing at the same commit, eg:
+- Retarget multiple branches pointing at the same commit, eg:
   > updated branch my-cool-branch: deadbeef -> c0ffee
 
 # Version 0.2.3
 
-* Allow setting the diff theme
-* Read configuration from git config as well as arguments and env vars
-* Choose whether to display full diff or just a diffstat based on terminal
+- Allow setting the diff theme
+- Read configuration from git config as well as arguments and env vars
+- Choose whether to display full diff or just a diffstat based on terminal
   height instead of a constant
-* Add -u alias for --default-upstream-branch
+- Add -u alias for --default-upstream-branch
 
 # Version 0.2.2
 
-* Correctly retarget branches if the target of the edit is also a branch (#24)
-* Check if main, master, develop, or trunk exist as reasonable default upstream branches
-* Leave the repo in a less confusing state if the edit target is a conflict
+- Correctly retarget branches if the target of the edit is also a branch (#24)
+- Check if main, master, develop, or trunk exist as reasonable default upstream branches
+- Leave the repo in a less confusing state if the edit target is a conflict
 
 # Version 0.2.1
 
-* Remove last dependency on external git binary, using libgit2 for all git interactions
-* Show backtraces on error if RUST_BACKTRACE=1 is in the environment
-* Correctly stash and unstash changes before the rebase
+- Remove last dependency on external git binary, using libgit2 for all git interactions
+- Show backtraces on error if RUST_BACKTRACE=1 is in the environment
+- Correctly stash and unstash changes before the rebase
 
 # Version 0.2.0
 
-* Rename to git-instafix because there are a bunch of existing projects named git-fixup
+- Rename to git-instafix because there are a bunch of existing projects named git-fixup
 
 # Version 0.1.9
 
-* CI and doc improvements
-* Use libgit2 instead of shelling out for more things.
-* Create binaries and install scripts with cargo-dist
+- CI and doc improvements
+- Use libgit2 instead of shelling out for more things.
+- Create binaries and install scripts with cargo-dist

src/selecter.rs

@@ -5,17 +5,14 @@ use std::collections::HashMap;
 use anyhow::{anyhow, bail};
 use console::style;
 use dialoguer::Select;
-use git2::BranchType;
-use git2::Commit;
-use git2::Oid;
-use git2::{Branch, Repository};
+use git2::{Branch, BranchType, Commit, Oid, Reference, Repository};
 
 use crate::config;
 use crate::format_ref;
 
 pub(crate) struct CommitSelection<'a> {
     pub commit: Commit<'a>,
-    pub branch: Branch<'a>,
+    pub reference: Reference<'a>,
 }
 
 pub(crate) fn select_commit_to_amend<'a>(
@@ -38,9 +35,9 @@ pub(crate) fn select_commit_to_amend<'a>(
         let head = repo.head()?;
         let current_branch_name = head
             .shorthand()
-            .ok_or_else(|| anyhow!("HEAD is not a branch"))?;
+            .ok_or_else(|| anyhow!("HEAD's name is invalid utf-8"))?;
         if repo.head()?.peel_to_commit()?.id() == upstream.commit.id()
-            && current_branch_name == upstream.branch.name().unwrap().unwrap()
+            && current_branch_name == upstream.reference.name().unwrap()
         {
             let upstream_setting = config::UPSTREAM_SETTING;
             bail!(
@@ -132,24 +129,18 @@ pub(crate) fn get_merge_base<'a>(
     upstream_name: Option<&str>,
 ) -> Result<Option<CommitSelection<'a>>, anyhow::Error> {
     let (upstream, branch) = if let Some(explicit_upstream_name) = upstream_name {
-        let mut bt = BranchType::Local;
-        let branch = repo
-            .find_branch(explicit_upstream_name, BranchType::Local)
-            .or_else(|_| {
-                bt = BranchType::Remote;
-                repo.find_branch(explicit_upstream_name, BranchType::Remote)
-            })?;
-        let b2 = repo.find_branch(explicit_upstream_name, bt)?;
-        (branch.into_reference().peel_to_commit()?, b2)
+        let reference = repo.resolve_reference_from_short_name(explicit_upstream_name)?;
+        let r2 = repo.resolve_reference_from_short_name(explicit_upstream_name)?;
+        (reference.peel_to_commit()?, r2)
     } else if let Some(branch) = find_default_upstream_branch(repo) {
         (
             branch.into_reference().peel_to_commit()?,
-            find_default_upstream_branch(repo).unwrap(),
+            find_default_upstream_branch(repo).unwrap().into_reference(),
         )
     } else if let Ok(upstream) = head_branch.upstream() {
         (
             upstream.into_reference().peel_to_commit()?,
-            head_branch.upstream().unwrap(),
+            head_branch.upstream().unwrap().into_reference(),
         )
     } else {
         return Ok(None);
@@ -166,7 +157,7 @@ pub(crate) fn get_merge_base<'a>(
 
     Ok(Some(CommitSelection {
         commit: commit.peel_to_commit()?,
-        branch,
+        reference: branch,
     }))
 }
 

tests/basic.rs

@@ -153,6 +153,127 @@ new
     );
 }
 
+#[test]
+fn simple_straightline_tag_and_reference() {
+    let td = assert_fs::TempDir::new().unwrap();
+    git_init(&td);
+
+    let base = "v0.1.0";
+
+    git_commits(&["a", "b"], &td);
+    git(&["tag", base], &td);
+    git(&["checkout", "-b", "changes"], &td);
+    git_commits(&["target", "d"], &td);
+
+    let log = git_log(&td);
+    assert_eq!(
+        log,
+        "\
+* d HEAD -> changes
+* target
+* b tag: v0.1.0, main
+* a
+",
+        "log:\n{}",
+        log
+    );
+
+    td.child("new").touch().unwrap();
+    git(&["add", "new"], &td);
+
+    fixup(&td)
+        .args(["-P", "target", "-u", base])
+        .assert()
+        .success();
+
+    let (files, err) = git_changed_files("target", &td);
+
+    assert_eq!(
+        files,
+        "\
+file_target
+new
+",
+        "out: {} err: {}",
+        files,
+        err
+    );
+
+    // also check that we can use the full refspec definition
+
+    td.child("new-full-ref").touch().unwrap();
+    git(&["add", "new-full-ref"], &td);
+    fixup(&td)
+        .args(["-P", "target", "-u", &format!("refs/tags/{base}")])
+        .unwrap();
+
+    let (files, err) = git_changed_files("target", &td);
+    assert_eq!(
+        files,
+        "\
+file_target
+new
+new-full-ref
+",
+        "out: {} err: {}",
+        files,
+        err
+    );
+}
+
+#[test]
+fn simple_straightline_remote_branch() {
+    let remote_td = assert_fs::TempDir::new().unwrap();
+    git_init(&remote_td);
+    git_commits(&["a", "b"], &remote_td);
+
+    let td = assert_fs::TempDir::new().unwrap();
+    git_init(&td);
+    let remote_path = &remote_td
+        .path()
+        .as_os_str()
+        .to_owned()
+        .into_string()
+        .unwrap();
+    git(&["remote", "add", "origin", remote_path], &td);
+    git(&["pull", "origin", "main:main"], &td);
+    git_commits(&["target", "d"], &td);
+
+    let log = git_log(&td);
+    assert_eq!(
+        log,
+        "\
+* d HEAD -> main
+* target
+* b origin/main
+* a
+",
+        "log:\n{}",
+        log
+    );
+
+    td.child("new").touch().unwrap();
+    git(&["add", "new"], &td);
+
+    fixup(&td)
+        .args(["-P", "target", "-u", "origin/main"])
+        .assert()
+        .success();
+
+    let (files, err) = git_changed_files("target", &td);
+
+    assert_eq!(
+        files,
+        "\
+file_target
+new
+",
+        "out: {} err: {}",
+        files,
+        err
+    );
+}
+
 #[test]
 fn stashes_before_rebase() {
     let td = assert_fs::TempDir::new().unwrap();
@@ -389,7 +510,7 @@ fn git_init_default_branch_name(name: &str, tempdir: &assert_fs::TempDir) {
 fn git_file_commit(name: &str, tempdir: &assert_fs::TempDir) {
     tempdir.child(format!("file_{}", name)).touch().unwrap();
     git(&["add", "-A"], tempdir);
-    git(&["commit", "-m", &name], tempdir);
+    git(&["commit", "-m", name], tempdir);
 }
 
 /// Get the git shown output for the target commit