autostage: enable behavior only if enabled via config

README.md

@@ -104,6 +104,17 @@ To always have this behavior, set
     oneFixupPerCommit = true
 ```
 
+### Auto-stage all changes if nothing staged
+
+By default, git-absorb will only consider files that you've staged to the index via `git add`. However, sometimes one wants to try and absorb from all changes, which would require to stage them first via `git add .`. To avoid this extra step, set
+
+```ini
+[absorb]
+	autoStageIfNothingStaged = true
+```
+
+which tells git-absorb, when no changes are staged, to auto-stage them all, create fixup commits where possible, and unstage remaining changes from the index.
+
 ## TODO
 
 - implement force flag

src/config.rs

@@ -4,6 +4,9 @@ pub const MAX_STACK: usize = 10;
 pub const ONE_FIXUP_PER_COMMIT_CONFIG_NAME: &str = "absorb.oneFixupPerCommit";
 pub const ONE_FIXUP_PER_COMMIT_DEFAULT: bool = false;
 
+pub const AUTO_STAGE_IF_NOTHING_STAGED_CONFIG_NAME: &str = "absorb.autoStageIfNothingStaged";
+pub const AUTO_STAGE_IF_NOTHING_STAGED_DEFAULT: bool = false;
+
 pub fn max_stack(repo: &git2::Repository) -> usize {
     match repo
         .config()
@@ -23,3 +26,13 @@ pub fn one_fixup_per_commit(repo: &git2::Repository) -> bool {
         _ => ONE_FIXUP_PER_COMMIT_DEFAULT,
     }
 }
+
+pub fn auto_stage_if_nothing_staged(repo: &git2::Repository) -> bool {
+    match repo
+        .config()
+        .and_then(|config| config.get_bool(AUTO_STAGE_IF_NOTHING_STAGED_CONFIG_NAME))
+    {
+        Ok(val) => val,
+        _ => AUTO_STAGE_IF_NOTHING_STAGED_DEFAULT,
+    }
+}

src/lib.rs

@@ -45,8 +45,9 @@ fn run_with_repo(config: &Config, repo: &git2::Repository) -> Result<()> {
         return Ok(());
     }
 
+    let autostage_enabled: bool = config::auto_stage_if_nothing_staged(repo);
     let mut we_added_everything_to_index = false;
-    if nothing_left_in_index(repo)? {
+    if autostage_enabled && nothing_left_in_index(repo)? {
         we_added_everything_to_index = true;
 
         // no matter from what subdirectory we're executing,
@@ -333,7 +334,7 @@ fn run_with_repo(config: &Config, repo: &git2::Repository) -> Result<()> {
         }
     }
 
-    if we_added_everything_to_index {
+    if autostage_enabled && we_added_everything_to_index {
         // now that the fixup commits have been created,
         // we should unstage the remaining changes from the index.
 
@@ -601,20 +602,33 @@ lines
         assert!(nothing_left_in_index(&ctx.repo).unwrap());
     }
 
-    #[test]
-    fn auto_add_everything_to_index_if_index_was_empty() {
-        let (ctx, file_path) = prepare_repo();
-
-        // 1 modification w/o staging - should get fixup commit created
+    fn autostage_common(ctx: &Context, file_path: &PathBuf) -> (PathBuf, PathBuf) {
+        // 1 modification w/o staging
         let path = ctx.join(&file_path);
         let contents = std::fs::read_to_string(&path).unwrap();
         let modifications = format!("{contents}\nnew_line2");
         std::fs::write(&path, &modifications).unwrap();
 
-        // 1 extra file that should get staged & later removed from the index
+        // 1 extra file
         let fp2 = PathBuf::from("unrel.txt");
         std::fs::write(ctx.join(&fp2), "foo").unwrap();
 
+        (path, fp2)
+    }
+
+    #[test]
+    fn auto_add_everything_to_index_if_index_was_empty() {
+        let (ctx, file_path) = prepare_repo();
+
+        // requires enabled config var
+        ctx.repo
+            .config()
+            .unwrap()
+            .set_bool(config::AUTO_STAGE_IF_NOTHING_STAGED_CONFIG_NAME, true)
+            .unwrap();
+
+        autostage_common(&ctx, &file_path);
+
         // run 'git-absorb'
         let drain = slog::Discard;
         let logger = slog::Logger::root(drain, o!());
@@ -637,18 +651,40 @@ lines
     }
 
     #[test]
-    fn do_not_add_anything_extra_if_index_was_not_empty() {
+    fn do_not_auto_add_anything_to_index_if_not_enabled_by_config_var() {
         let (ctx, file_path) = prepare_repo();
 
-        // 1 modification w/o staging - should not get staged nor fixed up
-        let path = ctx.join(&file_path);
-        let contents = std::fs::read_to_string(&path).unwrap();
-        let modifications = format!("{contents}\nnew_line2");
-        std::fs::write(&path, &modifications).unwrap();
+        assert_eq!(config::auto_stage_if_nothing_staged(&ctx.repo), false);
 
-        // 1 extra file that we'll stage - should stay in index
-        let fp2 = PathBuf::from("unrel.txt");
-        std::fs::write(ctx.join(&fp2), "foo").unwrap();
+        autostage_common(&ctx, &file_path);
+
+        // run 'git-absorb'
+        let drain = slog::Discard;
+        let logger = slog::Logger::root(drain, o!());
+        let config = Config {
+            dry_run: false,
+            force: false,
+            base: None,
+            and_rebase: false,
+            whole_file: false,
+            one_fixup_per_commit: false,
+            logger: &logger,
+        };
+        run_with_repo(&config, &ctx.repo).unwrap();
+
+        let mut revwalk = ctx.repo.revwalk().unwrap();
+        revwalk.push_head().unwrap();
+        assert_eq!(revwalk.count(), 1);
+
+        assert_eq!(index_stats(&ctx.repo).unwrap().files_changed(), 0);
+    }
+
+    #[test]
+    fn do_not_add_anything_extra_if_index_was_not_empty() {
+        let (ctx, file_path) = prepare_repo();
+
+        let (_, fp2) = autostage_common(&ctx, &file_path);
+        // we stage the extra file - should stay in index
         add(&ctx.repo, &fp2);
 
         // run 'git-absorb'