Guards: remove default-case outcome hook · github/codeql@6aedc51 · GitHub
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owen-mcCopilot
owen-mc
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Guards: remove default-case outcome hook
Align Go with Java and C# by deriving useful default-branch facts from the preceding non-match edges rather than treating the default clause itself as a true guard. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
1 parent 480e631 commit 6aedc51

5 files changed

Lines changed: 4 additions & 59 deletions

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‎go/ql/lib/semmle/go/controlflow/Guards.qll‎

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‎go/ql/test/library-tests/semmle/go/controlflow/Guards/Guards.expected‎

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Original file line numberDiff line numberDiff line change
@@ -4,12 +4,10 @@ controlsResult
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| guards.go:12:7:12:15 | ...<... | zero | false |
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| guards.go:14:7:14:16 | ...==... | positive | false |
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| guards.go:14:7:14:16 | ...==... | zero | true |
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| guards.go:16:2:17:18 | case clause | positive | true |
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| guards.go:23:2:24:21 | case clause | tagged one or two | false |
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| guards.go:23:2:24:21 | case clause | tagged other | false |
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| guards.go:23:2:24:21 | case clause | tagged zero | true |
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| guards.go:25:2:26:27 | case clause | tagged other | false |
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| guards.go:27:2:28:22 | case clause | tagged other | true |
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| guards.go:34:2:35:30 | case clause | tagged false boolean | true |
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| guards.go:34:7:34:11 | value | tagged false boolean | false |
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| guards.go:38:2:39:29 | case clause | tagged true boolean | true |
@@ -42,14 +40,10 @@ controlsResult
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| guards.go:126:5:126:28 | ...==... | source non-nil return | true |
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| guards.go:137:2:138:26 | case clause | default case | false |
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| guards.go:137:2:138:26 | case clause | non-default case | true |
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| guards.go:139:2:140:22 | case clause | default case | true |
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| guards.go:146:2:147:29 | case clause | default before case | true |
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| guards.go:148:2:149:28 | case clause | case after default | true |
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| guards.go:148:2:149:28 | case clause | default before case | false |
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| guards.go:155:2:156:22 | case clause | default only | true |
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| guards.go:162:7:162:11 | value | expressionless case | true |
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| guards.go:162:7:162:11 | value | expressionless default | false |
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| guards.go:164:2:165:32 | case clause | expressionless default | true |
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| guards.go:183:5:183:21 | call to isNotNil | non-variadic wrapper | true |
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| guards.go:194:5:194:32 | call to namedResultIsNotNil | named result wrapper | true |
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| guards.go:208:5:208:43 | call to conditionalNamedResultIsNotNil | conditional named result wrapper | true |
@@ -75,7 +69,6 @@ valueControlsResult
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| guards.go:14:7:14:11 | value | zero | 0 |
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| guards.go:14:7:14:16 | ...==... | positive | false |
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| guards.go:14:7:14:16 | ...==... | zero | true |
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| guards.go:16:2:17:18 | case clause | positive | true |
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| guards.go:22:9:22:13 | value | tagged one or two | not 0 |
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| guards.go:22:9:22:13 | value | tagged other | not 0 |
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| guards.go:22:9:22:13 | value | tagged other | not 1 |
@@ -85,7 +78,6 @@ valueControlsResult
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| guards.go:23:2:24:21 | case clause | tagged other | false |
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| guards.go:23:2:24:21 | case clause | tagged zero | true |
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| guards.go:25:2:26:27 | case clause | tagged other | false |
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| guards.go:27:2:28:22 | case clause | tagged other | true |
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| guards.go:34:2:35:30 | case clause | tagged false boolean | true |
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| guards.go:34:7:34:11 | value | tagged false boolean | false |
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| guards.go:38:2:39:29 | case clause | tagged true boolean | true |
@@ -150,16 +142,12 @@ valueControlsResult
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| guards.go:136:9:136:13 | value | non-default case | 0 |
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| guards.go:137:2:138:26 | case clause | default case | false |
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| guards.go:137:2:138:26 | case clause | non-default case | true |
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| guards.go:139:2:140:22 | case clause | default case | true |
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| guards.go:145:9:145:13 | value | case after default | 0 |
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| guards.go:145:9:145:13 | value | default before case | not 0 |
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| guards.go:146:2:147:29 | case clause | default before case | true |
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| guards.go:148:2:149:28 | case clause | case after default | true |
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| guards.go:148:2:149:28 | case clause | default before case | false |
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| guards.go:155:2:156:22 | case clause | default only | true |
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| guards.go:162:7:162:11 | value | expressionless case | true |
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| guards.go:162:7:162:11 | value | expressionless default | false |
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| guards.go:164:2:165:32 | case clause | expressionless default | true |
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| guards.go:183:5:183:21 | call to isNotNil | non-variadic wrapper | no exception |
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| guards.go:183:5:183:21 | call to isNotNil | non-variadic wrapper | true |
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| guards.go:183:14:183:20 | pointer | non-variadic wrapper | not null |
@@ -265,13 +253,6 @@ ensuresEqResult
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| guards.go:383:5:383:34 | ...==... | nil = call to modelNullGuard | true |
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| guards.go:386:5:386:37 | ...!=... | call to modelNotNullGuard = nil | false |
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| guards.go:386:5:386:37 | ...!=... | nil = call to modelNotNullGuard | false |
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defaultCaseResult
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| guards.go:16:2:17:18 | case clause | positive | true |
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| guards.go:27:2:28:22 | case clause | tagged other | true |
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| guards.go:139:2:140:22 | case clause | default case | true |
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| guards.go:146:2:147:29 | case clause | default before case | true |
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| guards.go:155:2:156:22 | case clause | default only | true |
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| guards.go:164:2:165:32 | case clause | expressionless default | true |
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modelBarrierResult
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| guards.go:375:27:375:33 | pointer | model bool | model-bool |
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| guards.go:378:27:378:33 | pointer | model zero | model-zero |

‎go/ql/test/library-tests/semmle/go/controlflow/Guards/Guards.ql‎

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Original file line numberDiff line numberDiff line change
@@ -31,16 +31,6 @@ query predicate ensuresEqResult(Guard guard, string label, string outcome) {
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)
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}
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query predicate defaultCaseResult(Guard guard, string label, string outcome) {
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exists(DataFlow::CallNode call, GuardValue value, CaseClause defaultCase |
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sinkCall(call, label) and
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defaultCase = any(ExpressionSwitchStmt switch).getDefault() and
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guard = defaultCase and
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guard.valueControls(call.getBasicBlock(), value) and
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outcome = value.toString()
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)
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}
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query predicate modelBarrierResult(DataFlow::Node node, string label, string kind) {
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exists(DataFlow::CallNode call |
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call.getTarget().getName() = "valueSink" and

‎go/ql/test/library-tests/semmle/go/controlflow/Guards/guards.go‎

Lines changed: 4 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -137,14 +137,14 @@ func defaultCase(value int) {
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case 0:
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sink("non-default case")
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default:
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sink("default case") // default case matches
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sink("default case")
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}
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}
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func defaultBeforeCase(value int) {
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switch value {
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default:
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sink("default before case") // default case matches
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sink("default before case")
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case 0:
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sink("case after default")
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}
@@ -153,7 +153,7 @@ func defaultBeforeCase(value int) {
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func defaultOnly(value int) {
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switch value {
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default:
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sink("default only") // default case matches
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sink("default only") // No guard fact: matching the only case is tautological.
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}
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}
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@@ -162,7 +162,7 @@ func expressionlessDefault(value bool) {
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case value:
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sink("expressionless case")
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default:
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sink("expressionless default") // default case matches
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sink("expressionless default")
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}
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}
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‎shared/controlflow/codeql/controlflow/Guards.qll‎

Lines changed: 0 additions & 16 deletions

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