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| author | Andrew Gerrand <adg@golang.org> | 2019-05-31 16:58:44 +1000 |
|---|---|---|
| committer | Andrew Gerrand <adg@golang.org> | 2019-06-03 01:37:58 +0000 |
| commit | 98100c56da0da1503e7612921eff821409aa6cce (patch) | |
| tree | 391e06eb2476bfc0b59e22183c0a6d84f9744716 /src/cmd/cover | |
| parent | ce656af9b5d9acb817b4de5170a11a2c42ad2047 (diff) | |
| download | go-98100c56da0da1503e7612921eff821409aa6cce.tar.gz go-98100c56da0da1503e7612921eff821409aa6cce.zip | |
cmd/cover: fix counting of blocks split by goto statements
When adding coverage counters to a block, the block's statement list is
mutated. CL 77150 removed the part where the mutated list is assigned
back to its parent node; this was confusing ast.Walk, which would then
lose its place and stop walking the current block, dropping counters in
the process.
This change has addCounters make a copy of the list before mutating
it, so that the original list doesn't change under Walk's feet.
Fix #32200
Change-Id: Ia3b67d8cee860ceb7caf8748cb7a80ff9c6276e0
Reviewed-on: https://go-review.googlesource.com/c/go/+/179581
Reviewed-by: Rob Pike <r@golang.org>
Diffstat (limited to 'src/cmd/cover')
| -rw-r--r-- | src/cmd/cover/cover.go | 3 | ||||
| -rw-r--r-- | src/cmd/cover/testdata/test.go | 4 |
2 files changed, 7 insertions, 0 deletions
diff --git a/src/cmd/cover/cover.go b/src/cmd/cover/cover.go index 1748606c5e..e04c8834bd 100644 --- a/src/cmd/cover/cover.go +++ b/src/cmd/cover/cover.go @@ -386,6 +386,9 @@ func (f *File) addCounters(pos, insertPos, blockEnd token.Pos, list []ast.Stmt, f.edit.Insert(f.offset(insertPos), f.newCounter(insertPos, blockEnd, 0)+";") return } + // Make a copy of the list, as we may mutate it and should leave the + // existing list intact. + list = append([]ast.Stmt(nil), list...) // We have a block (statement list), but it may have several basic blocks due to the // appearance of statements that affect the flow of control. for { diff --git a/src/cmd/cover/testdata/test.go b/src/cmd/cover/testdata/test.go index 0b03ef91ab..b794962205 100644 --- a/src/cmd/cover/testdata/test.go +++ b/src/cmd/cover/testdata/test.go @@ -132,6 +132,10 @@ func testBlockRun() { func testSwitch() { for i := 0; i < 5; func() { i++; check(LINE, 5) }() { + goto label2 + label1: + goto label1 + label2: switch i { case 0: check(LINE, 1) |