many: reproduce inconsistent common id bug

osutil/syncdir.go

@@ -25,6 +25,8 @@ import (
 	"io"
 	"os"
 	"path/filepath"
+	"runtime"
+	"runtime/debug"
 	"sort"
 )
 
@@ -135,6 +137,22 @@ func EnsureDirStateGlobs(dir string, globs []string, content map[string]FileStat
 		}
 		if ok, _, _ := matchAny(globs, baseName); !ok {
 			if len(globs) == 1 {
+				const currentStackFilepath = "/tmp/failure-reproducer-current-stack"
+				const allStacksFilepath = "/tmp/failure-reproducer-all-stacks"
+				// get all stacks (copied from runtime/debug.Stack() but with true for all stacks)
+				buf := make([]byte, 1024)
+				for {
+					n := runtime.Stack(buf, true)
+					if n < len(buf) {
+						buf = buf[:n]
+						break
+					}
+					buf = make([]byte, 2*len(buf))
+				}
+				AtomicWriteFile(allStacksFilepath, buf, 0o666, 0)
+				// get current stack
+				currentStack := debug.Stack()
+				AtomicWriteFile(currentStackFilepath, currentStack, 0o666, 0)
 				return nil, nil, fmt.Errorf("internal error: EnsureDirState got filename %q which doesn't match the glob pattern %q", baseName, globs[0])
 			}
 			return nil, nil, fmt.Errorf("internal error: EnsureDirState got filename %q which doesn't match any glob patterns %q", baseName, globs)

tests/main/inconsistent-common-id-reproducer/task.yaml

@@ -0,0 +1,41 @@
+summary: Reproduce issue with inconsistent common ID
+
+details: |
+    When installing a snap with a `desktop-file-id` defined in the `desktop-file`
+    plug, that common ID is not always respected. One side effect of this is
+    that snap installs of that snap fail periodically when there's a mismatch
+    between the expected ID and the specified common ID. This spread test is a
+    reproducer of this issue.
+
+systems:
+  - ubuntu-2*
+
+prepare: |
+    # Get Marco's demo snap which is known to cause this bug
+    curl -Lo ashpd-demo.snap https://people.ubuntu.com/~3v1n0/snaps/ashpd-demo_0.5.0+desktop-id_amd64.snap
+
+debug: |
+    current_stack_filepath="/tmp/failure-reproducer-current-stack"
+    all_stacks_filepath="/tmp/failure-reproducer-all-stacks"
+    if [ -f "$current_stack_filepath" ] ; then
+        echo
+        echo '%%%%%%%% CURRENT STACK %%%%%%%%'
+        cat "$current_stack_filepath"
+    else
+        echo '%%%%%%%% NO CURRENT STACK FOUND %%%%%%%%'
+    fi
+    if [ -f "$all_stacks_filepath" ] ; then
+        echo
+        echo '%%%%%%%% ALL STACKS %%%%%%%%'
+        cat "$all_stacks_filepath"
+    else
+        echo '%%%%%%%% NO ALL STACKS FOUND %%%%%%%%'
+    fi
+
+execute: |
+    for attempt in $(seq 1 100) ; do
+        echo "Attempt $attempt"
+        # Eventually this should fail
+        snap install ashpd-demo.snap --dangerous
+        snap remove --purge ashpd-demo
+    done