fix: Fixed markdown verbose printing too large outputs

[Benjas333]

Changed

• sem diff --format markdown now uses TextDiff to reduce the output length.

Decided to open a PR so that when you can review #65, you can decide to accept or deny this PR.
Closes #65

Before

crates/sem-cli/src/formatters/markdown.rs

Status	Type	Name
Δ	function	format_markdown

format_markdown

- pub fn format_markdown(result: &DiffResult, verbose: bool) -> String {
-     if result.changes.is_empty() {
-         return "No semantic changes detected.".to_string();
-     }
-
-     let mut lines: Vec<String> = Vec::new();
-
-     // Group changes by file (BTreeMap for sorted output)
-     let mut by_file: BTreeMap<&str, Vec<usize>> = BTreeMap::new();
-     for (i, change) in result.changes.iter().enumerate() {
-         by_file.entry(&change.file_path).or_default().push(i);
-     }
-
-     for (file_path, indices) in &by_file {
-         lines.push(format!("### {file_path}"));
-         lines.push(String::new());
-         lines.push("| Status | Type | Name |".to_string());
-         lines.push("|--------|------|------|".to_string());
-
-         let mut post_table: Vec<String> = Vec::new();
-
-         for &idx in indices {
-             let change = &result.changes[idx];
-             let status = match change.change_type {
-                 ChangeType::Added => "+",
-                 ChangeType::Deleted => "-",
-                 ChangeType::Modified => {
-                     if change.structural_change == Some(false) {
-                         "~"
-                     } else {
-                         "Δ"
-                     }
-                 }
-                 ChangeType::Moved => "→",
-                 ChangeType::Renamed => "↻",
-             };
-
-             let name_display = if let Some(ref old_name) = change.old_entity_name {
-                 format!("{old_name} -> {}", change.entity_name)
-             } else {
-                 change.entity_name.clone()
-             };
-             lines.push(format!(
-                 "| {} | {} | {} |",
-                 status, change.entity_type, name_display
-             ));
-
-             // Show content diff
-             if verbose {
-                 match change.change_type {
-                     ChangeType::Added => {
-                         if let Some(ref content) = change.after_content {
-                             post_table.push(String::new());
-                             post_table.push(format!("**`{}`**", change.entity_name));
-                             post_table.push("```diff".to_string());
-                             for line in content.lines() {
-                                 post_table.push(format!("+ {line}"));
-                             }
-                             post_table.push("```".to_string());
-                         }
-                     }
-                     ChangeType::Deleted => {
-                         if let Some(ref content) = change.before_content {
-                             post_table.push(String::new());
-                             post_table.push(format!("**`{}`**", change.entity_name));
-                             post_table.push("```diff".to_string());
-                             for line in content.lines() {
-                                 post_table.push(format!("- {line}"));
-                             }
-                             post_table.push("```".to_string());
-                         }
-                     }
-                     ChangeType::Modified => {
-                         if let (Some(before), Some(after)) =
-                             (&change.before_content, &change.after_content)
-                         {
-                             post_table.push(String::new());
-                             post_table.push(format!("**`{}`**", change.entity_name));
-                             post_table.push("```diff".to_string());
-                             for line in before.lines() {
-                                 post_table.push(format!("- {line}"));
-                             }
-                             for line in after.lines() {
-                                 post_table.push(format!("+ {line}"));
-                             }
-                             post_table.push("```".to_string());
-                         }
-                     }
-                     _ => {}
-                 }
-             } else if change.change_type == ChangeType::Modified {
-                 if let (Some(before), Some(after)) =
-                     (&change.before_content, &change.after_content)
-                 {
-                     let before_lines: Vec<&str> = before.lines().collect();
-                     let after_lines: Vec<&str> = after.lines().collect();
-
-                     if before_lines.len() <= 3 && after_lines.len() <= 3 {
-                         post_table.push(String::new());
-                         post_table.push(format!("**`{}`**", change.entity_name));
-                         post_table.push("```diff".to_string());
-                         for line in &before_lines {
-                             post_table.push(format!("- {}", line.trim()));
-                         }
-                         for line in &after_lines {
-                             post_table.push(format!("+ {}", line.trim()));
-                         }
-                         post_table.push("```".to_string());
-                     }
-                 }
-             }
-
-             // Show rename/move details
-             if matches!(
-                 change.change_type,
-                 ChangeType::Renamed | ChangeType::Moved
-             ) {
-                 if let Some(ref old_path) = change.old_file_path {
-                     post_table.push(String::new());
-                     post_table.push(format!("> from {old_path}"));
-                 }
-             }
-         }
-
-         lines.extend(post_table);
-         lines.push(String::new());
-     }
-
-     // Summary
-     let mut parts: Vec<String> = Vec::new();
-     if result.added_count > 0 {
-         parts.push(format!("{} added", result.added_count));
-     }
-     if result.modified_count > 0 {
-         parts.push(format!("{} modified", result.modified_count));
-     }
-     if result.deleted_count > 0 {
-         parts.push(format!("{} deleted", result.deleted_count));
-     }
-     if result.moved_count > 0 {
-         parts.push(format!("{} moved", result.moved_count));
-     }
-     if result.renamed_count > 0 {
-         parts.push(format!("{} renamed", result.renamed_count));
-     }
-
-     let files_label = if result.file_count == 1 {
-         "file"
-     } else {
-         "files"
-     };
-
-     lines.push(format!(
-         "**Summary:** {} across {} {files_label}",
-         parts.join(", "),
-         result.file_count,
-     ));
-
-     lines.join("\n")
- }
+ pub fn format_markdown(result: &DiffResult, verbose: bool) -> String {
+     if result.changes.is_empty() {
+         return "No semantic changes detected.".to_string();
+     }
+
+     let mut lines: Vec<String> = Vec::new();
+
+     // Group changes by file (BTreeMap for sorted output)
+     let mut by_file: BTreeMap<&str, Vec<usize>> = BTreeMap::new();
+     for (i, change) in result.changes.iter().enumerate() {
+         by_file.entry(&change.file_path).or_default().push(i);
+     }
+
+     for (file_path, indices) in &by_file {
+         lines.push(format!("### {file_path}"));
+         lines.push(String::new());
+         lines.push("| Status | Type | Name |".to_string());
+         lines.push("|--------|------|------|".to_string());
+
+         let mut post_table: Vec<String> = Vec::new();
+
+         for &idx in indices {
+             let change = &result.changes[idx];
+             let status = match change.change_type {
+                 ChangeType::Added => "+",
+                 ChangeType::Deleted => "-",
+                 ChangeType::Modified => {
+                     if change.structural_change == Some(false) {
+                         "~"
+                     } else {
+                         "Δ"
+                     }
+                 }
+                 ChangeType::Moved => "→",
+                 ChangeType::Renamed => "↻",
+             };
+
+             let name_display = if let Some(ref old_name) = change.old_entity_name {
+                 format!("{old_name} -> {}", change.entity_name)
+             } else {
+                 change.entity_name.clone()
+             };
+             lines.push(format!(
+                 "| {} | {} | {} |",
+                 status, change.entity_type, name_display
+             ));
+
+             // Show content diff
+             if verbose {
+                 match change.change_type {
+                     ChangeType::Added => {
+                         if let Some(ref content) = change.after_content {
+                             post_table.push(String::new());
+                             post_table.push(format!("**`{}`**", change.entity_name));
+                             post_table.push("```diff".to_string());
+                             for line in content.lines() {
+                                 post_table.push(format!("+ {line}"));
+                             }
+                             post_table.push("```".to_string());
+                         }
+                     }
+                     ChangeType::Deleted => {
+                         if let Some(ref content) = change.before_content {
+                             post_table.push(String::new());
+                             post_table.push(format!("**`{}`**", change.entity_name));
+                             post_table.push("```diff".to_string());
+                             for line in content.lines() {
+                                 post_table.push(format!("- {line}"));
+                             }
+                             post_table.push("```".to_string());
+                         }
+                     }
+                     ChangeType::Modified => {
+                         if let (Some(before), Some(after)) =
+                             (&change.before_content, &change.after_content)
+                         {
+                             post_table.push(String::new());
+                             post_table.push(format!("**`{}`**", change.entity_name));
+                             post_table.push("```diff".to_string());
+                             let diff = TextDiff::from_lines(before.as_str(), after.as_str());
+                             for hunk in diff.unified_diff().context_radius(2).iter_hunks() {
+                                 post_table.push(hunk.header().to_string());
+                                 for op in hunk.ops() {
+                                     let mut deletes: Vec<String> = Vec::new();
+                                     let mut inserts: Vec<String> = Vec::new();
+
+                                     for diff_change in diff.iter_changes(op) {
+                                         let line = diff_change.value().trim_end_matches('\n');
+                                         match diff_change.tag() {
+                                             ChangeTag::Delete => deletes.push(line.to_string()),
+                                             ChangeTag::Insert => inserts.push(line.to_string()),
+                                             ChangeTag::Equal => post_table.push(format!("  {line}")),
+                                         }
+                                     }
+
+                                     let paired = deletes.len().min(inserts.len());
+                                     for i in 0..paired {
+                                         post_table.push(format!("- {}", deletes[i]));
+                                         post_table.push(format!("+ {}", inserts[i]));
+                                     }
+                                     for d in &deletes[paired..] {
+                                         post_table.push(format!("- {d}"));
+                                     }
+                                     for i in &inserts[paired..] {
+                                         post_table.push(format!("+ {i}"));
+                                     }
+                                 }
+                             }
+                             post_table.push("```".to_string());
+                         }
+                     }
+                     _ => {}
+                 }
+             } else if change.change_type == ChangeType::Modified {
+                 if let (Some(before), Some(after)) =
+                     (&change.before_content, &change.after_content)
+                 {
+                     let before_lines: Vec<&str> = before.lines().collect();
+                     let after_lines: Vec<&str> = after.lines().collect();
+
+                     if before_lines.len() <= 3 && after_lines.len() <= 3 {
+                         post_table.push(String::new());
+                         post_table.push(format!("**`{}`**", change.entity_name));
+                         post_table.push("```diff".to_string());
+                         for line in &before_lines {
+                             post_table.push(format!("- {}", line.trim()));
+                         }
+                         for line in &after_lines {
+                             post_table.push(format!("+ {}", line.trim()));
+                         }
+                         post_table.push("```".to_string());
+                     }
+                 }
+             }
+
+             // Show rename/move details
+             if matches!(
+                 change.change_type,
+                 ChangeType::Renamed | ChangeType::Moved
+             ) {
+                 if let Some(ref old_path) = change.old_file_path {
+                     post_table.push(String::new());
+                     post_table.push(format!("> from {old_path}"));
+                 }
+             }
+         }
+
+         lines.extend(post_table);
+         lines.push(String::new());
+     }
+
+     // Summary
+     let mut parts: Vec<String> = Vec::new();
+     if result.added_count > 0 {
+         parts.push(format!("{} added", result.added_count));
+     }
+     if result.modified_count > 0 {
+         parts.push(format!("{} modified", result.modified_count));
+     }
+     if result.deleted_count > 0 {
+         parts.push(format!("{} deleted", result.deleted_count));
+     }
+     if result.moved_count > 0 {
+         parts.push(format!("{} moved", result.moved_count));
+     }
+     if result.renamed_count > 0 {
+         parts.push(format!("{} renamed", result.renamed_count));
+     }
+
+     let files_label = if result.file_count == 1 {
+         "file"
+     } else {
+         "files"
+     };
+
+     lines.push(format!(
+         "**Summary:** {} across {} {files_label}",
+         parts.join(", "),
+         result.file_count,
+     ));
+
+     lines.join("\n")
+ }

Summary: 1 modified across 1 file

After

crates/sem-cli/src/formatters/markdown.rs

Status	Type	Name
Δ	function	format_markdown

format_markdown

@@ -78,9 +78,32 @@
                              post_table.push(format!("**`{}`**", change.entity_name));
                              post_table.push("```diff".to_string());
-                             for line in before.lines() {
+                             let diff = TextDiff::from_lines(before.as_str(), after.as_str());
-                                 post_table.push(format!("- {line}"));
+                             for hunk in diff.unified_diff().context_radius(2).iter_hunks() {
-                             }
+                                 post_table.push(hunk.header().to_string());
-                             for line in after.lines() {
+                                 for op in hunk.ops() {
-                                 post_table.push(format!("+ {line}"));
+                                     let mut deletes: Vec<String> = Vec::new();
+                                     let mut inserts: Vec<String> = Vec::new();
+
+                                     for diff_change in diff.iter_changes(op) {
+                                         let line = diff_change.value().trim_end_matches('\n');
+                                         match diff_change.tag() {
+                                             ChangeTag::Delete => deletes.push(line.to_string()),
+                                             ChangeTag::Insert => inserts.push(line.to_string()),
+                                             ChangeTag::Equal => post_table.push(format!("  {line}")),
+                                         }
+                                     }
+
+                                     let paired = deletes.len().min(inserts.len());
+                                     for i in 0..paired {
+                                         post_table.push(format!("- {}", deletes[i]));
+                                         post_table.push(format!("+ {}", inserts[i]));
+                                     }
+                                     for d in &deletes[paired..] {
+                                         post_table.push(format!("- {d}"));
+                                     }
+                                     for i in &inserts[paired..] {
+                                         post_table.push(format!("+ {i}"));
+                                     }
+                                 }
                              }
                              post_table.push("```".to_string());

Summary: 1 modified across 1 file

[rs545837]

Thanks for opening the PR, yeah I didn't get time to design a solid case for markdown files. I will review this PR soon.

[Benjas333]

Sorry for the large commit history. Didn't know I was doing git rebase wrong this whole time. My bad.

[Benjas333]

Now it's fixed. Sorry for the inconvenience.