Files
act_runner/act/runner/action_composite_test.go
Nicolas eeb479ea89 fix: prevent exponential growth of RunContext masks in composite actions (#1059)
A composite action's `RunContext` is **seeded with its parent's `Masks` slice** in `newCompositeRunContext`. After the composite finished running, the *entire* `compositeRC.Masks` (the seeded parent masks plus any added during the run) was appended straight back into the parent:

```go
rc.Masks = append(rc.Masks, compositeRC.Masks...)
```

Because the composite already contained the parent's masks, every composite action roughly **doubled** the parent's `Masks` length. With many nested/repeated composite actions this grows exponentially:

```
before=1152 after=2304 compositeLen=1152
before=2304 after=4608 compositeLen=2304
before=4608 after=9216 compositeLen=4608
...
```

### Impact

The bloated `Masks` slice made per-log-line secret redaction (`strings.makeGenericReplacer`, rebuilt per line since #1001) extremely slow. Log writes fell behind enough to keep subprocess pipes open after the process had already exited, surfacing as seemingly random CI failures — most often in later steps of mask-heavy workflows:

```
Error: exec: WaitDelay expired before I/O complete
```

The split of `cmd.Run()` into `cmd.Start()` + `cmd.Wait()` (#883) is what turned this long-standing latency into a hard failure.

### Fix

Only append masks that aren't already present in the parent, via a small `appendUniqueMasks` helper. This keeps the mask count bounded by the number of *distinct* secrets instead of growing exponentially.

I kept `Masks` as a `[]string` rather than switching to a set type, since it's passed by pointer to loggers across `logger.go`, `run_context.go`, and `runner.go` — a type change would be a much wider, riskier refactor. The `O(n·m)` dedup is harmless precisely because `n` now stays small.

Fixes #1054Reviewed-on: https://gitea.com/gitea/runner/pulls/1059
Reviewed-by: Lunny Xiao <xiaolunwen@gmail.com>
2026-07-01 18:50:34 +00:00

71 lines
1.7 KiB
Go

// Copyright 2026 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package runner
import (
"testing"
"github.com/stretchr/testify/assert"
)
func TestAppendUniqueMasks(t *testing.T) {
tests := []struct {
name string
dst []string
src []string
want []string
}{
{
name: "appends new masks",
dst: []string{"a"},
src: []string{"b", "c"},
want: []string{"a", "b", "c"},
},
{
name: "skips masks already present",
dst: []string{"a", "b"},
src: []string{"a", "b"},
want: []string{"a", "b"},
},
{
name: "deduplicates within src",
dst: []string{"a"},
src: []string{"b", "b", "a"},
want: []string{"a", "b"},
},
{
name: "empty src leaves dst unchanged",
dst: []string{"a"},
src: nil,
want: []string{"a"},
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
assert.Equal(t, tt.want, appendUniqueMasks(tt.dst, tt.src))
})
}
}
// TestAppendUniqueMasksNoExponentialGrowth reproduces the exponential growth of
// the parent's Masks slice observed with nested/repeated composite actions. A
// composite RunContext is seeded with its parent's masks and the whole seeded
// slice was previously appended back into the parent, doubling its length on
// every composite action.
func TestAppendUniqueMasksNoExponentialGrowth(t *testing.T) {
parentMasks := []string{"secret"}
for range 20 {
// compositeRC.Masks starts as a copy of the parent's masks (it is
// seeded with parent.Masks in newCompositeRunContext).
compositeMasks := make([]string, len(parentMasks))
copy(compositeMasks, parentMasks)
parentMasks = appendUniqueMasks(parentMasks, compositeMasks)
}
assert.Equal(t, []string{"secret"}, parentMasks)
}