From 5a02eb65ef2c4b860cebeb2e6329778d28f45d43 Mon Sep 17 00:00:00 2001
From: Robert Griesemer <gri@golang.org>
Date: Wed, 28 Oct 2009 10:14:59 -0700
Subject: [PATCH] fix for long label names impacting column width of previous
 lines

R=rsc
http://go/go-review/1013017
---
 src/pkg/go/printer/printer.go                 |  7 ++++++-
 src/pkg/go/printer/testdata/statements.go     | 17 +++++++++++++++++
 src/pkg/go/printer/testdata/statements.golden | 17 +++++++++++++++++
 3 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/src/pkg/go/printer/printer.go b/src/pkg/go/printer/printer.go
index 01f45356f6..50dcffd866 100644
--- a/src/pkg/go/printer/printer.go
+++ b/src/pkg/go/printer/printer.go
@@ -418,7 +418,12 @@ func (p *printer) writeWhitespace(n int) {
 			// part of the comment whitespace prefix and the comment
 			// will be positioned correctly indented.
 			if i+1 < n && p.buffer[i+1] == unindent {
-				p.buffer[i], p.buffer[i+1] = unindent, ch;
+				// Use a formfeed to terminate the current section.
+				// Otherwise, a long label name on the next line leading
+				// to a wide column may increase the indentation column
+				// of lines before the label; effectively leading to wrong
+				// indentation.
+				p.buffer[i], p.buffer[i+1] = unindent, formfeed;
 				i--;  // do it again
 				continue;
 			}
diff --git a/src/pkg/go/printer/testdata/statements.go b/src/pkg/go/printer/testdata/statements.go
index 85cb5989ce..c58131f0b6 100644
--- a/src/pkg/go/printer/testdata/statements.go
+++ b/src/pkg/go/printer/testdata/statements.go
@@ -156,3 +156,20 @@ func _() {
 		_ = 0;
 	}
 }
+
+
+func _() {
+	if {
+		_ = 0;
+	}
+	_ = 0;  // the indentation here should not be affected by the long label name
+AnOverlongLabel:
+	_ = 0;
+	
+	if {
+		_ = 0;
+	}
+	_ = 0;
+
+L:	_ = 0;
+}
diff --git a/src/pkg/go/printer/testdata/statements.golden b/src/pkg/go/printer/testdata/statements.golden
index 3d8d424c10..16392806ae 100644
--- a/src/pkg/go/printer/testdata/statements.golden
+++ b/src/pkg/go/printer/testdata/statements.golden
@@ -174,3 +174,20 @@ func _() {
 		_ = 0;
 	}
 }
+
+
+func _() {
+	if {
+		_ = 0;
+	}
+	_ = 0;	// the indentation here should not be affected by the long label name
+AnOverlongLabel:
+	_ = 0;
+
+	if {
+		_ = 0;
+	}
+	_ = 0;
+
+L:	_ = 0;
+}
-- 
2.50.0