don't emit organize-imports code action when result is identical

src/features/code_actions.zig

@@ -8,6 +8,7 @@ const DocumentStore = @import("../DocumentStore.zig");
 const DocumentScope = @import("../DocumentScope.zig");
 const Analyser = @import("../analysis.zig");
 const ast = @import("../ast.zig");
+const diff = @import("../diff.zig");
 const types = @import("lsp").types;
 const offsets = @import("../offsets.zig");
 const tracy = @import("tracy");
@@ -682,6 +683,9 @@ fn handleUnorganizedImport(builder: *Builder) error{OutOfMemory}!void {
         }
     }
 
+    const resulting_source = try diff.applyTextEdits(builder.arena, tree.source, edits.items, builder.offset_encoding);
+    if (std.mem.eql(u8, resulting_source, tree.source)) return;
+
     const workspace_edit = try builder.createWorkspaceEdit(edits.items);
 
     try builder.actions.append(builder.arena, .{

tests/lsp_features/code_actions.zig

@@ -762,6 +762,31 @@ test "organize imports - edge cases" {
     );
 }
 
+test "organize imports - no action when already organized" {
+    // Single import plus the trailing blank line that organize would normalize to.
+    // https://github.com/zigtools/zls/issues/2523
+    try testOrganizeImportsNoAction(
+        \\const a = @import("a");
+        \\
+        \\
+    );
+    // Sorted imports from different kinds with the expected group separator and trailing blank line.
+    try testOrganizeImportsNoAction(
+        \\const std = @import("std");
+        \\
+        \\const abc = @import("abc.zig");
+        \\
+        \\
+    );
+    // Imports already sorted, separated from following decls by the expected blank line.
+    try testOrganizeImportsNoAction(
+        \\const std = @import("std");
+        \\
+        \\fn main() void {}
+        \\
+    );
+}
+
 test "convert multiline string literal" {
     try testConvertString(
         \\const foo = \\Hell<cursor>o
@@ -960,6 +985,42 @@ fn testOrganizeImports(before: []const u8, after: []const u8) !void {
     try testDiagnostic(before, after, .{ .filter_kind = .@"source.organizeImports" });
 }
 
+fn testOrganizeImportsNoAction(source: []const u8) !void {
+    var ctx: Context = try .init();
+    defer ctx.deinit();
+
+    var phr = try helper.collectClearPlaceholders(allocator, source);
+    defer phr.deinit(allocator);
+    const clean_source = phr.new_source;
+
+    const range: types.Range = .{
+        .start = .{ .line = 0, .character = 0 },
+        .end = offsets.indexToPosition(clean_source, clean_source.len, ctx.server.offset_encoding),
+    };
+
+    const uri = try ctx.addDocument(.{ .source = clean_source });
+
+    const params: types.CodeAction.Params = .{
+        .textDocument = .{ .uri = uri.raw },
+        .range = range,
+        .context = .{
+            .diagnostics = &.{},
+            .only = &.{.@"source.organizeImports"},
+        },
+    };
+
+    @setEvalBranchQuota(5000);
+    const response = try ctx.server.sendRequestSync(ctx.arena.allocator(), "textDocument/codeAction", params) orelse return;
+
+    for (response) |action| {
+        const kind = action.code_action.kind orelse continue;
+        if (kind == .@"source.organizeImports") {
+            std.debug.print("expected no organize-imports code action for already-organized source, got: {s}\n", .{action.code_action.title});
+            return error.UnexpectedOrganizeImportsAction;
+        }
+    }
+}
+
 fn testConvertString(before: []const u8, after: []const u8) !void {
     try testDiagnostic(before, after, .{ .filter_kind = .refactor });
 }