go/printer: fix format with leading comments in composite literal
This fix is less pervasive than it seems. The only change affecting
formatting is on printer.go:760. The remaining changes have no effect
on formatting since the value of p.level is ignored except on this
specific line.
The remaining changes are:
- renamed adjBlock to funcBody since that's how it is used
- introduced new printer field 'level' tracking the composite
literal nesting level
- update/restore the composite literal nesting level as needed
Fixes #18782.
Change-Id: Ie833a9b5a559c4ec0f2eef2c5dc97aa263dca53a
Reviewed-on: https://go-review.googlesource.com/35811
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
diff --git a/src/go/printer/nodes.go b/src/go/printer/nodes.go
index 11f26d4..ea43286 100644
--- a/src/go/printer/nodes.go
+++ b/src/go/printer/nodes.go
@@ -733,7 +733,7 @@
case *ast.FuncLit:
p.expr(x.Type)
- p.adjBlock(p.distanceFrom(x.Type.Pos()), blank, x.Body)
+ p.funcBody(p.distanceFrom(x.Type.Pos()), blank, x.Body)
case *ast.ParenExpr:
if _, hasParens := x.X.(*ast.ParenExpr); hasParens {
@@ -825,6 +825,7 @@
if x.Type != nil {
p.expr1(x.Type, token.HighestPrec, depth)
}
+ p.level++
p.print(x.Lbrace, token.LBRACE)
p.exprList(x.Lbrace, x.Elts, 1, commaTerm, x.Rbrace)
// do not insert extra line break following a /*-style comment
@@ -837,6 +838,7 @@
mode |= noExtraBlank
}
p.print(mode, x.Rbrace, token.RBRACE, mode)
+ p.level--
case *ast.Ellipsis:
p.print(token.ELLIPSIS)
@@ -1557,18 +1559,23 @@
return bodySize
}
-// adjBlock prints an "adjacent" block (e.g., a for-loop or function body) following
-// a header (e.g., a for-loop control clause or function signature) of given headerSize.
+// funcBody prints a function body following a function header of given headerSize.
// If the header's and block's size are "small enough" and the block is "simple enough",
// the block is printed on the current line, without line breaks, spaced from the header
// by sep. Otherwise the block's opening "{" is printed on the current line, followed by
// lines for the block's statements and its closing "}".
//
-func (p *printer) adjBlock(headerSize int, sep whiteSpace, b *ast.BlockStmt) {
+func (p *printer) funcBody(headerSize int, sep whiteSpace, b *ast.BlockStmt) {
if b == nil {
return
}
+ // save/restore composite literal nesting level
+ defer func(level int) {
+ p.level = level
+ }(p.level)
+ p.level = 0
+
const maxSize = 100
if headerSize+p.bodySize(b, maxSize) <= maxSize {
p.print(sep, b.Lbrace, token.LBRACE)
@@ -1613,7 +1620,7 @@
}
p.expr(d.Name)
p.signature(d.Type.Params, d.Type.Results)
- p.adjBlock(p.distanceFrom(d.Pos()), vtab, d.Body)
+ p.funcBody(p.distanceFrom(d.Pos()), vtab, d.Body)
}
func (p *printer) decl(decl ast.Decl) {
diff --git a/src/go/printer/printer.go b/src/go/printer/printer.go
index eabf23e..be61dad 100644
--- a/src/go/printer/printer.go
+++ b/src/go/printer/printer.go
@@ -58,6 +58,7 @@
// Current state
output []byte // raw printer result
indent int // current indentation
+ level int // level == 0: outside composite literal; level > 0: inside composite literal
mode pmode // current printer mode
impliedSemi bool // if set, a linebreak implies a semicolon
lastTok token.Token // last token printed (token.ILLEGAL if it's whitespace)
@@ -744,15 +745,19 @@
// follows on the same line but is not a comma, and not a "closing"
// token immediately following its corresponding "opening" token,
// add an extra separator unless explicitly disabled. Use a blank
- // as separator unless we have pending linebreaks and they are not
- // disabled, in which case we want a linebreak (issue 15137).
+ // as separator unless we have pending linebreaks, they are not
+ // disabled, and we are outside a composite literal, in which case
+ // we want a linebreak (issue 15137).
+ // TODO(gri) This has become overly complicated. We should be able
+ // to track whether we're inside an expression or statement and
+ // use that information to decide more directly.
needsLinebreak := false
if p.mode&noExtraBlank == 0 &&
last.Text[1] == '*' && p.lineFor(last.Pos()) == next.Line &&
tok != token.COMMA &&
(tok != token.RPAREN || p.prevOpen == token.LPAREN) &&
(tok != token.RBRACK || p.prevOpen == token.LBRACK) {
- if p.containsLinebreak() && p.mode&noExtraLinebreak == 0 {
+ if p.containsLinebreak() && p.mode&noExtraLinebreak == 0 && p.level == 0 {
needsLinebreak = true
} else {
p.writeByte(' ', 1)
diff --git a/src/go/printer/testdata/comments2.golden b/src/go/printer/testdata/comments2.golden
index 7676a26..8b3a94d 100644
--- a/src/go/printer/testdata/comments2.golden
+++ b/src/go/printer/testdata/comments2.golden
@@ -103,3 +103,62 @@
mask := uint64(1)<<c - 1 // Allocation mask
used := atomic.LoadUint64(&h.used) // Current allocations
}
+
+// Test cases for issue 18782
+var _ = [][]int{
+ /* a, b, c, d, e */
+ /* a */ {0, 0, 0, 0, 0},
+ /* b */ {0, 5, 4, 4, 4},
+ /* c */ {0, 4, 5, 4, 4},
+ /* d */ {0, 4, 4, 5, 4},
+ /* e */ {0, 4, 4, 4, 5},
+}
+
+var _ = T{ /* a */ 0}
+
+var _ = T{ /* a */ /* b */ 0}
+
+var _ = T{ /* a */ /* b */
+ /* c */ 0,
+}
+
+var _ = T{ /* a */ /* b */
+ /* c */
+ /* d */ 0,
+}
+
+var _ = T{
+ /* a */
+ /* b */ 0,
+}
+
+var _ = T{ /* a */ {}}
+
+var _ = T{ /* a */ /* b */ {}}
+
+var _ = T{ /* a */ /* b */
+ /* c */ {},
+}
+
+var _ = T{ /* a */ /* b */
+ /* c */
+ /* d */ {},
+}
+
+var _ = T{
+ /* a */
+ /* b */ {},
+}
+
+var _ = []T{
+ func() {
+ var _ = [][]int{
+ /* a, b, c, d, e */
+ /* a */ {0, 0, 0, 0, 0},
+ /* b */ {0, 5, 4, 4, 4},
+ /* c */ {0, 4, 5, 4, 4},
+ /* d */ {0, 4, 4, 5, 4},
+ /* e */ {0, 4, 4, 4, 5},
+ }
+ },
+}
diff --git a/src/go/printer/testdata/comments2.input b/src/go/printer/testdata/comments2.input
index 4a055c8..8d38c41 100644
--- a/src/go/printer/testdata/comments2.input
+++ b/src/go/printer/testdata/comments2.input
@@ -103,3 +103,66 @@
mask := uint64(1)<<c - 1 // Allocation mask
used := atomic.LoadUint64(&h.used) // Current allocations
}
+
+// Test cases for issue 18782
+var _ = [][]int{
+ /* a, b, c, d, e */
+ /* a */ {0, 0, 0, 0, 0},
+ /* b */ {0, 5, 4, 4, 4},
+ /* c */ {0, 4, 5, 4, 4},
+ /* d */ {0, 4, 4, 5, 4},
+ /* e */ {0, 4, 4, 4, 5},
+}
+
+var _ = T{ /* a */ 0,
+}
+
+var _ = T{ /* a */ /* b */ 0,
+}
+
+var _ = T{ /* a */ /* b */
+ /* c */ 0,
+}
+
+var _ = T{ /* a */ /* b */
+ /* c */
+ /* d */ 0,
+}
+
+var _ = T{
+ /* a */
+ /* b */ 0,
+}
+
+var _ = T{ /* a */ {},
+}
+
+var _ = T{ /* a */ /* b */ {},
+}
+
+var _ = T{ /* a */ /* b */
+ /* c */ {},
+}
+
+var _ = T{ /* a */ /* b */
+ /* c */
+ /* d */ {},
+}
+
+var _ = T{
+ /* a */
+ /* b */ {},
+}
+
+var _ = []T{
+ func() {
+ var _ = [][]int{
+ /* a, b, c, d, e */
+ /* a */ {0, 0, 0, 0, 0},
+ /* b */ {0, 5, 4, 4, 4},
+ /* c */ {0, 4, 5, 4, 4},
+ /* d */ {0, 4, 4, 5, 4},
+ /* e */ {0, 4, 4, 4, 5},
+ }
+ },
+}
