NI: introduce new data flow analysis for try/catch (#KT-28370)

2019-02-17 12:42:54 +03:00
parent a236ad5686
commit 4a298d1413
11 changed files with 464 additions and 2 deletions
@@ -0,0 +1,107 @@
+// !WITH_NEW_INFERENCE
+// !LANGUAGE: +NewDataFlowForTryExpressions
+// !DIAGNOSTICS: -UNUSED_VARIABLE -UNUSED_VALUE -VARIABLE_WITH_REDUNDANT_INITIALIZER
+// Related issue: KT-28370
+
+class ExcA : Exception()
+class ExcB : Exception()
+
+fun test1() {
+    var x: String? = null
+    x = ""
+
+    try {
+        x = null
+    } catch (e: Exception) {
+        <!OI;DEBUG_INFO_SMARTCAST!>x<!><!NI;UNSAFE_CALL!>.<!>length // smartcast shouldn't be allowed (OOME could happen after `x = null`)
+        throw e
+    }
+    finally {
+        // smartcast shouldn't be allowed, `x = null` could've happened
+        <!OI;DEBUG_INFO_SMARTCAST!>x<!><!NI;UNSAFE_CALL!>.<!>length
+    }
+    // smartcast shouldn't be allowed, `x = null` could've happened
+    <!OI;DEBUG_INFO_SMARTCAST!>x<!><!NI;UNSAFE_CALL!>.<!>length
+}
+
+// With old DFA of try/catch info about unsound smartcasts after try
+//  removes only if there is at least one catch branch that not returns Nothing
+fun test2() {
+    var x: String? = null
+    x = ""
+
+    try {
+        x = null
+    } catch (e: Exception) {
+        // BAD
+        <!OI;DEBUG_INFO_SMARTCAST!>x<!><!NI;UNSAFE_CALL!>.<!>length
+    }
+    finally {
+        x<!UNSAFE_CALL!>.<!>length
+    }
+    x<!UNSAFE_CALL!>.<!>length
+}
+
+fun test3() {
+    var t2: Boolean? = true
+    if (t2 != null) { // or `t2 is Boolean`
+        try {
+            throw Exception()
+        } catch (e: Exception) {
+            t2 = null
+        }
+        <!OI;DEBUG_INFO_SMARTCAST!>t2<!><!NI;UNSAFE_CALL!>.<!>not() // wrong smartcast, NPE
+    }
+}
+
+fun test4() {
+    var t2: Boolean? = true
+    if (t2 != null) { // or `t2 is Boolean`
+        try {
+            t2 = null
+        } finally { }
+        <!OI;DEBUG_INFO_SMARTCAST!>t2<!><!NI;UNSAFE_CALL!>.<!>not() // wrong smartcast, NPE
+    }
+}
+
+fun test5() {
+    var s1: String? = null
+    var s2: String? = null
+    s1 = ""
+    s2 = ""
+    try {
+        TODO()
+    }
+    catch (e: ExcA) {
+        s1 = ""
+    }
+    catch (e: ExcB) {
+        s2 = null
+        return
+    }
+    finally {
+        <!OI;DEBUG_INFO_SMARTCAST!>s1<!><!NI;UNSAFE_CALL!>.<!>length
+        <!OI;DEBUG_INFO_SMARTCAST!>s2<!><!NI;UNSAFE_CALL!>.<!>length
+    }
+    <!OI;DEBUG_INFO_SMARTCAST!>s1<!><!NI;UNSAFE_CALL!>.<!>length
+    <!DEBUG_INFO_SMARTCAST!>s2<!>.length
+}
+
+fun test6(s1: String?, s2: String?) {
+    var s: String? = null
+    s = ""
+    try {
+        s = null
+        requireNotNull(s1)
+    }
+    catch (e: Exception) {
+        return
+    }
+    finally {
+        <!OI;DEBUG_INFO_SMARTCAST!>s<!><!NI;UNSAFE_CALL!>.<!>length
+        requireNotNull(s2)
+    }
+    <!OI;DEBUG_INFO_SMARTCAST!>s<!><!NI;UNSAFE_CALL!>.<!>length
+    <!NI;DEBUG_INFO_SMARTCAST!>s1<!><!OI;UNSAFE_CALL!>.<!>length
+    <!DEBUG_INFO_SMARTCAST!>s2<!>.length
+}