feat(ssh_config): Add check for duplicate host names

handlers/ssh_config/analyzer/analyzer.go

@@ -40,6 +40,7 @@ func Analyze(
 	analyzeDependents(ctx)
 	analyzeBlocks(ctx)
 	analyzeMatchBlocks(ctx)
+	analyzeHostBlock(ctx)
 
 	return ctx.diagnostics
 }

handlers/ssh_config/analyzer/block.go

@@ -14,6 +14,7 @@ func analyzeBlocks(
 			continue
 		}
 
+		// Check if block is empty
 		if block.GetOptions().Size() == 0 {
 			ctx.diagnostics = append(ctx.diagnostics, protocol.Diagnostic{
 				Range:    block.GetEntryOption().LocationRange.ToLSPRange(),

handlers/ssh_config/analyzer/host.go

@@ -0,0 +1,33 @@
+package analyzer
+
+import (
+	"config-lsp/common"
+	hostparser "config-lsp/handlers/ssh_config/host-parser"
+	"fmt"
+
+	protocol "github.com/tliron/glsp/protocol_3_16"
+)
+
+func analyzeHostBlock(
+	ctx *analyzerContext,
+) {
+	hosts := make(map[string]*hostparser.HostValue, 0)
+
+	for _, block := range ctx.document.GetAllHostBlocks() {
+		if block == nil || block.HostValue == nil {
+			continue
+		}
+
+		for _, host := range block.HostValue.Hosts {
+			if _, found := hosts[host.Value.Value]; found {
+				ctx.diagnostics = append(ctx.diagnostics, protocol.Diagnostic{
+					Range:    host.ToLSPRange(),
+					Message:  fmt.Sprintf("Host %s has already been defined on line %d", host.Value.Value, hosts[host.Value.Value].Start.Line+1),
+					Severity: &common.SeverityError,
+				})
+			} else {
+				hosts[host.Value.Value] = host
+			}
+		}
+	}
+}

handlers/ssh_config/analyzer/host_test.go

@@ -0,0 +1,74 @@
+package analyzer
+
+import (
+	testutils_test "config-lsp/handlers/ssh_config/test_utils"
+	"testing"
+
+	protocol "github.com/tliron/glsp/protocol_3_16"
+)
+
+func TestDuplicateHostExample(
+	t *testing.T,
+) {
+	d := testutils_test.DocumentFromInput(t, `
+Host example.com
+	User root
+
+Host example.com
+	User test
+`)
+	ctx := &analyzerContext{
+		document:    d,
+		diagnostics: make([]protocol.Diagnostic, 0),
+	}
+
+	analyzeHostBlock(ctx)
+
+	if !(len(ctx.diagnostics) == 1) {
+		t.Errorf("Expected 1 error, got %v", len(ctx.diagnostics))
+	}
+}
+
+func TestDuplicateMultipleHostExample(
+	t *testing.T,
+) {
+	d := testutils_test.DocumentFromInput(t, `
+Host example.com google.com 
+	User root
+
+Host test.com example.com
+	User test
+`)
+	ctx := &analyzerContext{
+		document:    d,
+		diagnostics: make([]protocol.Diagnostic, 0),
+	}
+
+	analyzeHostBlock(ctx)
+
+	if !(len(ctx.diagnostics) == 1) {
+		t.Errorf("Expected 1 error, got %v", len(ctx.diagnostics))
+	}
+}
+
+func TestNonDuplicateHostExample(
+	t *testing.T,
+) {
+	d := testutils_test.DocumentFromInput(t, `
+Host example.com
+	User root
+
+Host example2.com
+	User test
+`)
+	ctx := &analyzerContext{
+		document:    d,
+		diagnostics: make([]protocol.Diagnostic, 0),
+	}
+
+	analyzeHostBlock(ctx)
+
+	if !(len(ctx.diagnostics) == 0) {
+		t.Errorf("Expected 0 error, got %v", len(ctx.diagnostics))
+	}
+}