IdMap unit'y test with assignments (and add but-testsupport::Sandbox)

This also makes the Sandbox more generally available, in support of a more
generalised testing style of somewhat higher-level functions that use the context.

Author: Byron

Cargo.lock

@@ -124,6 +124,7 @@ regex = { version = "1.11.3", default-features = false, features = ["std", "unic
 clap = { version = "4.5.53", default-features = false, features = ["derive", "std", "help", "unstable-markdown"]}
 tracing-forest = { version = "0.3.0" }
 sysinfo = { version = "0.37.2", default-features = false }
+shell-words = "1.1.0"
 
 [profile.release]
 # There are no overrides here as we optimise for fast release builds,

Cargo.toml

@@ -217,17 +217,44 @@ impl Snapshot {
 
         let ws = graph.to_workspace()?;
         let mut seen = BTreeSet::new();
-        for (ws_stack, in_workspace_stack_id) in
-            ws.stacks.iter().filter_map(|s| s.id.map(|id| (s, id)))
-        {
-            seen.insert(in_workspace_stack_id);
-            let Some(vb_stack) = self.content.branches.get_mut(&in_workspace_stack_id) else {
-                tracing::warn!(
-                    "Didn't find stack with id {in_workspace_stack_id} in branches metadata, and it would have to be created or old code may fail"
-                );
-                continue;
-            };
 
+        // Make sure we have a stack id, which is something that may not be the case in
+        // single-branch mode or in tests that start off with just a Git repository.
+        // Having stack IDs is useful and maybe one day we can pre-generate them just like we do here
+        // as they only have to be locally unique.
+        let workspace_unique_stack_id = |mut idx: usize| -> StackId {
+            let mut stack_id = StackId::from_number_for_testing(idx as u128);
+            while self.content.branches.contains_key(&stack_id) {
+                idx += 1;
+                stack_id = StackId::from_number_for_testing(idx as u128);
+            }
+            stack_id
+        };
+        let ws_stacks_to_represent_in_vb_toml: Vec<_> = ws
+            .stacks
+            .iter()
+            .enumerate()
+            .map(|(idx, s)| {
+                let id = s.id.unwrap_or_else(|| workspace_unique_stack_id(idx + 1));
+                (s, id, idx)
+            })
+            .collect();
+        for (ws_stack, in_workspace_stack_id, ws_stack_idx) in ws_stacks_to_represent_in_vb_toml {
+            seen.insert(in_workspace_stack_id);
+            let mut inserted_new_stack = false;
+            let vb_stack = self
+                .content
+                .branches
+                .entry(in_workspace_stack_id)
+                .or_insert_with(|| {
+                    inserted_new_stack = true;
+                    Stack::new_with_just_heads(
+                        vec![],
+                        gix::date::Time::now_utc().seconds as u128 * 1000,
+                        ws_stack_idx,
+                        true,
+                    )
+                });
             let made_heads_match = make_heads_match(ws_stack, vb_stack);
             if !vb_stack.in_workspace {
                 tracing::warn!(
@@ -242,16 +269,19 @@ impl Snapshot {
                 );
                 self.set_changed_to_necessitate_write();
             }
+            if inserted_new_stack {
+                self.set_changed_to_necessitate_write();
+            }
         }
 
-        let stack_ids_to_put_in_workspace: Vec<_> = sideeffect_free_meta
+        let stack_ids_to_remove_from_workspace: Vec<_> = sideeffect_free_meta
             .data()
             .branches
             .keys()
             .filter(|stack_id| !seen.contains(stack_id))
             .copied()
             .collect();
-        for stack_id_not_in_workspace in stack_ids_to_put_in_workspace {
+        for stack_id_not_in_workspace in stack_ids_to_remove_from_workspace {
             let vb_stack = self
                 .content
                 .branches

crates/but-meta/src/legacy.rs

@@ -11,13 +11,23 @@ doctest = false
 
 [features]
 snapbox = ["dep:snapbox"]
+sandbox = [
+    "dep:but-settings",
+    "dep:shell-words",
+    "dep:but-meta",
+    "dep:but-ctx"
+]
 
 [dependencies]
 but-graph.workspace = true
 but-core.workspace = true
+but-settings = { workspace = true, optional = true }
+but-meta = { workspace = true, optional = true }
+but-ctx = { workspace = true, optional = true }
 
-gix-testtools.workspace = true
+shell-words = {  workspace = true, optional = true }
 
+gix-testtools.workspace = true
 gix.workspace = true
 anyhow.workspace = true
 termtree = "0.5.1"

crates/but-testsupport/Cargo.toml

@@ -13,6 +13,11 @@ use gix_testtools::{Creation, tempfile};
 mod in_memory_meta;
 pub use in_memory_meta::{InMemoryRefMetadata, InMemoryRefMetadataHandle, StackState};
 
+#[cfg(feature = "sandbox")]
+mod sandbox;
+#[cfg(feature = "sandbox")]
+pub use sandbox::Sandbox;
+
 /// Choose a slightly more obvious, yet easy to type syntax than a function with 4 parameters.
 /// i.e. `hunk_header("-1,10", "+1,10")`.
 /// Returns `( (old_start, old_lines), (new_start, new_lines) )`.