Merge pull request #14700 from gitbutlerapp/GB-1745/support-anonymous-segments-in-but-status

fix(but): assign short IDs to anonymous segments

Author: slarse

crates/but/src/command/legacy/status/mod.rs

@@ -1281,16 +1281,22 @@ fn print_group(
                 branch_suffix.push(Span::styled(no_commits, t.hint));
             }
 
+            let (decoration_start, decoration_end) = if branch.is_empty() {
+                ("", "")
+            } else {
+                (" [", "]")
+            };
+
             output.branch(
                 Vec::from([Span::raw(format!("┊{notch}┄"))]),
                 BranchLineContent {
                     id: Vec::from([Span::styled(segment.short_id.clone(), t.cli_id)]),
-                    decoration_start: Vec::from([Span::raw(" [")]),
+                    decoration_start: Vec::from([Span::raw(decoration_start)]),
                     branch_name: Vec::from([
                         Span::styled(branch, t.local_branch),
                         Span::raw(workspace),
                     ]),
-                    decoration_end: Vec::from([Span::raw("]")]),
+                    decoration_end: Vec::from([Span::raw(decoration_end)]),
                     suffix: branch_suffix,
                 },
                 branch_cli_id,

crates/but/src/id/mod.rs

@@ -779,6 +779,10 @@ impl IdMap {
     }
 
     fn parse_element<'a>(&'a self, element: &str) -> anyhow::Result<Vec<Box<dyn Node<'a> + 'a>>> {
+        if element.is_empty() {
+            return Ok(vec![]);
+        }
+
         // Parse known suffixes.
         if let Some(prefix) = element.strip_suffix("@{stack}") {
             let mut matches = Vec::<Box<dyn Node<'a> + 'a>>::new();

crates/but/src/id/stacks_info.rs

@@ -88,24 +88,25 @@ fn populate_branch_short_ids(
         .iter_mut()
         .flat_map(|stack| stack.segments.iter_mut())
     {
-        let Some(branch_name) = segment.branch_name() else {
-            // The branch CliId is its name, so if this segment doesn't have a
-            // name, it doesn't need an ID.
-            continue;
-        };
-        segment.short_id = 'short_id: {
-            // Find first non-conflicting pair or triple (i.e. used in
-            // exactly one branch) and use it.
-            for candidate in branch_name.windows(2).chain(branch_name.windows(3)) {
-                if let Ok(short_id) = str::from_utf8(candidate)
-                    && let Some(true) = maybe_mark_used(candidate, id_usage)
-                {
-                    break 'short_id short_id.to_owned();
+        if let Some(branch_name) = segment.branch_name() {
+            segment.short_id = 'short_id: {
+                // Find first non-conflicting pair or triple (i.e. used in
+                // exactly one branch) and use it.
+                for candidate in branch_name.windows(2).chain(branch_name.windows(3)) {
+                    if let Ok(short_id) = str::from_utf8(candidate)
+                        && let Some(true) = maybe_mark_used(candidate, id_usage)
+                    {
+                        break 'short_id short_id.to_owned();
+                    }
                 }
-            }
-            // If none available, use next available ID.
-            id_usage.next_available()?.to_short_id()
-        };
+                // If none available, use next available ID.
+                id_usage.next_available()?.to_short_id()
+            };
+        } else {
+            // This sgement is anonymous, so we have no name to base the ID on. We just assign it a
+            // generic ID, which allows some rudimentary stuff to work (e.g. `but status`).
+            segment.short_id = id_usage.next_available()?.to_short_id();
+        }
     }
 
     Ok(())

crates/but/tests/but/command/status.rs

@@ -46,6 +46,33 @@ fn worktrees() {
         ]);
 }
 
+#[test]
+fn anonymous_segment() {
+    let env =
+        Sandbox::init_scenario_with_target_and_default_settings("one-stack-anonymous-segment");
+    env.setup_metadata(&["A"]);
+
+    env.but("status")
+        .assert()
+        .success()
+        .stderr_eq(snapbox::str![])
+        .stdout_eq(snapbox::str![[r#"
+╭┄zz [uncommitted] (no changes)
+┊
+┊╭┄g0
+┊●   b36b65c anonymous (no changes)
+┊│
+┊├┄h0 [A]
+┊●   9477ae7 add A
+├╯
+┊
+┴ 0dc3733 (common base) 2000-01-02 add M
+
+Hint: run `but help` for all commands
+
+"#]]);
+}
+
 #[test]
 fn unborn() {
     let env = Sandbox::open_scenario_with_target_and_default_settings("unborn");

crates/but/tests/fixtures/scenario/one-stack-anonymous-segment.sh

@@ -0,0 +1,23 @@
+#!/usr/bin/env bash
+
+set -eu -o pipefail
+
+source "${BASH_SOURCE[0]%/*}/shared.sh"
+
+### General Description
+
+# A workspace with one named branch and an unreferenced commit above it, projected as an
+# anonymous stack segment.
+git-init-frozen
+commit-file M
+setup_target_to_match_main
+
+git checkout -b A
+  commit-file A
+
+git checkout --detach
+  commit anonymous
+git branch -f A HEAD^
+
+# HEAD remains on the anonymous commit, so the workspace commit is created above it.
+create_workspace_commit_once