check branch name validity while typing

CHANGELOG.md

@@ -7,6 +7,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+## Added
+- check branch name validity while typing ([#559](https://github.com/extrawurst/gitui/issues/559))
+
 ## Fixed
 - do not allow to ignore .gitignore files ([#825](https://github.com/extrawurst/gitui/issues/825))
 - crash in shallow repo ([#836](https://github.com/extrawurst/gitui/issues/836))

asyncgit/src/sync/branch/mod.rs

@@ -12,7 +12,7 @@ use crate::{
     error::{Error, Result},
     sync::{utils, CommitId},
 };
-use git2::{BranchType, Repository};
+use git2::{Branch, BranchType, Repository};
 use scopetime::scope_time;
 use utils::get_head_repo;
 
@@ -90,6 +90,15 @@ impl BranchInfo {
     }
 }
 
+///
+pub fn validate_branch_name(name: &str) -> Result<bool> {
+    scope_time!("validate_branch_name");
+
+    let valid = Branch::name_is_valid(name)?;
+
+    Ok(valid)
+}
+
 /// returns a list of `BranchInfo` with a simple summary on each branch
 /// `local` filters for local branches otherwise remote branches will be returned
 pub fn get_branches_info(

asyncgit/src/sync/mod.rs

@@ -35,7 +35,7 @@ pub use branch::{
     get_branches_info, merge_commit::merge_upstream_commit,
     merge_ff::branch_merge_upstream_fastforward,
     merge_rebase::merge_upstream_rebase, rename::rename_branch,
-    BranchCompare, BranchInfo,
+    validate_branch_name, BranchCompare, BranchInfo,
 };
 pub use commit::{amend, commit, tag};
 pub use commit_details::{

src/components/create_branch.rs

@@ -12,12 +12,16 @@ use crate::{
 use anyhow::Result;
 use asyncgit::{sync, CWD};
 use crossterm::event::Event;
-use tui::{backend::Backend, layout::Rect, Frame};
+use easy_cast::Cast;
+use tui::{
+    backend::Backend, layout::Rect, widgets::Paragraph, Frame,
+};
 
 pub struct CreateBranchComponent {
     input: TextInputComponent,
     queue: Queue,
     key_config: SharedKeyConfig,
+    theme: SharedTheme,
 }
 
 impl DrawableComponent for CreateBranchComponent {
@@ -26,7 +30,10 @@ impl DrawableComponent for CreateBranchComponent {
         f: &mut Frame<B>,
         rect: Rect,
     ) -> Result<()> {
-        self.input.draw(f, rect)?;
+        if self.is_visible() {
+            self.input.draw(f, rect)?;
+            self.draw_warnings(f);
+        }
 
         Ok(())
     }
@@ -95,12 +102,13 @@ impl CreateBranchComponent {
         Self {
             queue,
             input: TextInputComponent::new(
-                theme,
+                theme.clone(),
                 key_config.clone(),
                 &strings::create_branch_popup_title(&key_config),
                 &strings::create_branch_popup_msg(&key_config),
                 true,
             ),
+            theme,
             key_config,
         }
     }
@@ -134,4 +142,35 @@ impl CreateBranchComponent {
             }
         }
     }
+
+    fn draw_warnings<B: Backend>(&self, f: &mut Frame<B>) {
+        let current_text = self.input.get_text();
+
+        if !current_text.is_empty() {
+            let valid = sync::validate_branch_name(current_text)
+                .unwrap_or_default();
+
+            if !valid {
+                let msg = strings::branch_name_invalid();
+                let msg_length: u16 = msg.len().cast();
+                let w = Paragraph::new(msg)
+                    .style(self.theme.text_danger());
+
+                let rect = {
+                    let mut rect = self.input.get_area();
+                    rect.y += rect.height.saturating_sub(1);
+                    rect.height = 1;
+                    let offset =
+                        rect.width.saturating_sub(msg_length + 1);
+                    rect.width =
+                        rect.width.saturating_sub(offset + 1);
+                    rect.x += offset;
+
+                    rect
+                };
+
+                f.render_widget(w, rect);
+            }
+        }
+    }
 }

src/strings.rs

@@ -83,6 +83,9 @@ pub fn commit_msg(_key_config: &SharedKeyConfig) -> String {
 pub fn commit_first_line_warning(count: usize) -> String {
     format!("[subject length: {}]", count)
 }
+pub const fn branch_name_invalid() -> &'static str {
+    "[invalid name]"
+}
 pub fn commit_editor_msg(_key_config: &SharedKeyConfig) -> String {
     r##"
 # Edit your commit message