temp(split): try out new commit message format

See arxanas#1462

Author: claytonrcarter

git-branchless-lib/src/git/diff.rs

@@ -3,7 +3,7 @@ use std::collections::HashMap;
 use std::path::PathBuf;
 use std::sync::{Arc, Mutex};
 
-use eyre::Context;
+use eyre::{Context, OptionExt};
 use itertools::Itertools;
 use scm_record::helpers::make_binary_description;
 use scm_record::{ChangeType, File, FileMode, Section, SectionChangedLine};
@@ -15,6 +15,17 @@ pub struct Diff<'repo> {
     pub(super) inner: git2::Diff<'repo>,
 }
 
+impl Diff<'_> {
+    /// Summarize this diff into a single line "short" format.
+    pub fn short_stats(&self) -> eyre::Result<String> {
+        let stats = self.inner.stats()?;
+        let buf = stats.to_buf(git2::DiffStatsFormat::SHORT, usize::MAX)?;
+        buf.as_str()
+            .ok_or_eyre("converting buf to str")
+            .map(|s| s.trim().to_string())
+    }
+}
+
 #[derive(Clone, Debug, PartialEq, Eq, Hash)]
 struct GitHunk {
     old_start: usize,
@@ -23,6 +34,59 @@ struct GitHunk {
     new_lines: usize,
 }
 
+/// Summarize a diff for use as part of a temporary commit message.
+pub fn summarize_diff_for_temporary_commit(diff: &Diff) -> eyre::Result<String> {
+    // this returns something like `1 file changed, 1 deletion(-)`
+    // diff.short_stats()
+
+    // this returns something like `test2.txt (-1)` or `2 files (+1/-2)`
+    let stats = diff.inner.stats()?;
+    let prefix = if stats.files_changed() == 1 {
+        let mut prefix = None;
+        // returning false terminates iteration, but that also returns Err, so
+        // catch and ignore it
+        let _ = diff.inner.foreach(
+            &mut |delta: git2::DiffDelta, _| {
+                if let Some(path) = delta.old_file().path() {
+                    // prefix = Some(format!("{}", path.file_name().unwrap().to_string_lossy()));
+                    prefix = Some(format!("{}", path.display()));
+                } else if let Some(path) = delta.new_file().path() {
+                    prefix = Some(format!("{}", path.display()));
+                }
+
+                false
+            },
+            None,
+            None,
+            None,
+        );
+        prefix
+    } else {
+        Some(format!("{} files", stats.files_changed()))
+    };
+
+    let i = stats.insertions();
+    let d = stats.deletions();
+    Ok(format!(
+        "{prefix} ({i}{slash}{d})",
+        prefix = prefix.unwrap(),
+        i = if i > 0 {
+            format!("+{i}")
+        } else {
+            String::new()
+        },
+        slash = if i > 0 && d > 0 { "/" } else { "" },
+        d = if d > 0 {
+            format!("-{d}")
+        } else {
+            String::new()
+        }
+    ))
+    // stats.files_changed()
+    // stats.insertions()
+    // stats.deletions()
+}
+
 /// Calculate the diff between the index and the working copy.
 pub fn process_diff_for_record(repo: &Repo, diff: &Diff) -> eyre::Result<Vec<File<'static>>> {
     let Diff { inner: diff } = diff;

git-branchless-lib/src/git/mod.rs

@@ -14,7 +14,7 @@ mod test;
 mod tree;
 
 pub use config::{Config, ConfigRead, ConfigValue, ConfigWrite};
-pub use diff::{process_diff_for_record, Diff};
+pub use diff::{process_diff_for_record, summarize_diff_for_temporary_commit, Diff};
 pub use index::{update_index, Index, IndexEntry, Stage, UpdateIndexCommand};
 pub use object::Commit;
 pub use oid::{MaybeZeroOid, NonZeroOid};

git-branchless/src/commands/split.rs

@@ -26,8 +26,8 @@ use lib::{
         },
     },
     git::{
-        make_empty_tree, CherryPickFastOptions, GitRunInfo, MaybeZeroOid, NonZeroOid, Repo,
-        ResolvedReferenceInfo,
+        make_empty_tree, summarize_diff_for_temporary_commit, CherryPickFastOptions, GitRunInfo,
+        MaybeZeroOid, NonZeroOid, Repo, ResolvedReferenceInfo,
     },
     try_exit_code,
     util::{ExitCode, EyreExitOr},
@@ -135,12 +135,6 @@ pub fn split(
         }
     };
 
-    let mut message = match files_to_extract.as_slice() {
-        [] => unreachable!("Clap should have required at least 1 file"),
-        [_] => None,
-        other => Some(format!("{} files", other.len())),
-    };
-
     for file in files_to_extract.iter() {
         let path = Path::new(&file).to_path_buf();
         let cwd = std::env::current_dir()?;
@@ -176,7 +170,6 @@ pub fn split(
             path
         };
         let path = path.as_path();
-        message = message.or(Some(path.to_string_lossy().to_string()));
 
         if let Ok(Some(false)) = target_commit.contains_touched_path(path) {
             writeln!(
@@ -227,7 +220,19 @@ pub fn split(
             .find_tree(temp_tree_oid)?
             .expect("should have been found");
     }
-    let message = message.expect("at least 1 file should have been given");
+    let message = {
+        let (effects, _progress) =
+            effects.start_operation(lib::core::effects::OperationType::CalculateDiff);
+        let (old_tree, new_tree) = (&remainder_tree, &target_tree);
+        let diff = repo.get_diff_between_trees(
+            &effects,
+            Some(old_tree),
+            new_tree,
+            0, // we don't care about the context here
+        )?;
+
+        summarize_diff_for_temporary_commit(&diff)?
+    };
 
     let remainder_commit_oid =
         target_commit.amend_commit(None, None, None, None, Some(&remainder_tree))?;

git-branchless/tests/test_split.rs

@@ -32,7 +32,7 @@ fn test_split_detached_head() -> eyre::Result<()> {
             |
             @ 2932db7 first commit
             |
-            o c159d6a temp(split): test2.txt
+            o 01523cc temp(split): test2.txt (+1)
         "###);
     }
 
@@ -91,7 +91,7 @@ fn test_split_added_file() -> eyre::Result<()> {
             |
             @ 2f9e232 first commit
             |
-            o 067feb9 temp(split): test2.txt
+            o c4b067e temp(split): test2.txt (+1)
         "###);
     }
 
@@ -148,7 +148,7 @@ fn test_split_modified_file() -> eyre::Result<()> {
             |
             @ 495b4c0 first commit
             |
-            o 590b05e temp(split): test1.txt
+            o 5375cb6 temp(split): test1.txt (+1/-1)
         "###);
     }
 
@@ -215,7 +215,7 @@ fn test_split_deleted_file() -> eyre::Result<()> {
             |
             @ 495b4c0 first commit
             |
-            o bfc063a temp(split): test1.txt
+            o de6e4df temp(split): test1.txt (-1)
         "###);
     }
 
@@ -268,7 +268,7 @@ fn test_split_multiple_files() -> eyre::Result<()> {
             |
             @ 8e5c74b first commit
             |
-            o 0b1f3c6 temp(split): 2 files
+            o 57020b0 temp(split): 2 files (+2)
         "###);
     }
 
@@ -324,7 +324,7 @@ fn test_split_detached_branch() -> eyre::Result<()> {
             |
             @ 2932db7 (branch-name) first commit
             |
-            o c159d6a temp(split): test2.txt
+            o 01523cc temp(split): test2.txt (+1)
         "###);
     }
 
@@ -368,7 +368,7 @@ fn test_split_attached_branch() -> eyre::Result<()> {
             |
             o 2932db7 first commit
             |
-            @ c159d6a (> branch-name) temp(split): test2.txt
+            @ 01523cc (> branch-name) temp(split): test2.txt (+1)
         "###);
 
         let (stdout, _stderr) = git.run(&["status", "--short"])?;
@@ -407,17 +407,17 @@ fn test_split_restacks_descendents() -> eyre::Result<()> {
         let (stdout, _stderr) = git.branchless("split", &["HEAD~", "test2.txt"])?;
         insta::assert_snapshot!(&stdout, @r###"
             Attempting rebase in-memory...
-            [1/1] Committed as: 71d03a3 create test3.txt
+            [1/1] Committed as: a629a22 create test3.txt
             branchless: processing 1 rewritten commit
-            branchless: running command: <git-executable> checkout 71d03a33c534eda4253fc8772a4c0d5e9515127c
+            branchless: running command: <git-executable> checkout a629a22974b9232523701e66e6e2bcdf8ffc8ad1
             In-memory rebase succeeded.
             O f777ecc (master) create initial.txt
             |
             o 2932db7 first commit
             |
-            o c159d6a temp(split): test2.txt
+            o 01523cc temp(split): test2.txt (+1)
             |
-            @ 71d03a3 create test3.txt
+            @ a629a22 create test3.txt
         "###);
     }
 
@@ -468,17 +468,17 @@ fn test_split_undo_works() -> eyre::Result<()> {
         let (stdout, _stderr) = git.branchless("split", &["HEAD~", "test2.txt"])?;
         insta::assert_snapshot!(&stdout, @r###"
             Attempting rebase in-memory...
-            [1/1] Committed as: 71d03a3 create test3.txt
+            [1/1] Committed as: a629a22 create test3.txt
             branchless: processing 1 rewritten commit
-            branchless: running command: <git-executable> checkout 71d03a33c534eda4253fc8772a4c0d5e9515127c
+            branchless: running command: <git-executable> checkout a629a22974b9232523701e66e6e2bcdf8ffc8ad1
             In-memory rebase succeeded.
             O f777ecc (master) create initial.txt
             |
             o 2932db7 first commit
             |
-            o c159d6a temp(split): test2.txt
+            o 01523cc temp(split): test2.txt (+1)
             |
-            @ 71d03a3 create test3.txt
+            @ a629a22 create test3.txt
         "###);
     }
 
@@ -561,7 +561,7 @@ fn test_split_supports_absolute_relative_and_repo_relative_paths() -> eyre::Resu
             |
             @ d9d41a3 first commit
             |
-            o fc76a91 temp(split): subdir/test3.txt
+            o 98da165 temp(split): subdir/test3.txt (+1)
         "###);
 
         let (stdout, _stderr) = git.run(&["show", "--pretty=format:", "--stat", "HEAD"])?;
@@ -593,7 +593,7 @@ fn test_split_supports_absolute_relative_and_repo_relative_paths() -> eyre::Resu
             |
             @ 0cb8154 first commit
             |
-            o 5d2c1d0 temp(split): subdir/test1.txt
+            o 89564a0 temp(split): subdir/test1.txt (+1)
         "###);
 
         let (stdout, _stderr) = git.run(&["show", "--pretty=format:", "--stat", "HEAD"])?;
@@ -625,7 +625,7 @@ fn test_split_supports_absolute_relative_and_repo_relative_paths() -> eyre::Resu
             |
             @ 9122046 first commit
             |
-            o ba3abaf temp(split): test2.txt
+            o c3d37e6 temp(split): test2.txt (+1)
         "###);
 
         let (stdout, _stderr) = git.run(&["show", "--pretty=format:", "--stat", "HEAD"])?;
@@ -657,7 +657,7 @@ fn test_split_supports_absolute_relative_and_repo_relative_paths() -> eyre::Resu
             |
             @ 6d0cd9b first commit
             |
-            o 2f03a38 temp(split): test1.txt
+            o 9eeb11b temp(split): test1.txt (+1)
         "###);
 
         let (stdout, _stderr) = git.run(&["show", "--pretty=format:", "--stat", "HEAD"])?;