Analysis Details

Use a Try-With-Resources Statement to Safely Handle Closeable Resources

es.uniovi.reflection.analyses.cmu.err54

We detect when a local variable that implements java.lang.AutoCloseable is not initialized in a try-with-resources statement, and the code may throw an exception before calling close. In that case, a try-with-resources statement is advised to the programmer.

Computational Reflection Research Group

05-08-2024 22:58

Reliability

Local Variable Definition

MATCH (rhs)<-[:ASSIGNMENT_RHS |:INITIALIZATION_EXPR]-(assignOrInit)<-[:MODIFIED_BY | HAS_VARIABLEDECL_INIT]-(closeableDec:LOCAL_VAR_DEF)-[:ITS_TYPE_IS]->(closeableSubtype)-[:IS_SUBTYPE_EXTENDS | IS_SUBTYPE_IMPLEMENTS*0..]->(closeableInt:INTERFACE_DEF{fullyQualifiedName:'java.lang.AutoCloseable'}) 
WHERE NOT rhs:LITERAL
WITH closeableDec, assignOrInit
OPTIONAL MATCH (closeableDec)<-[tryResourcesRel:TRY_RESOURCES]-() 
WITH tryResourcesRel,closeableDec,assignOrInit
WHERE tryResourcesRel IS NULL 
MATCH (assignOrInit)<-[:ARRAYACCESS_EXPR | ARRAYACCESS_INDEX | ASSIGNMENT_RHS | BINOP_LHS | BINOP_RHS | BINOP_COND_RHS | CAST_ENCLOSES | COMPOUND_ASSIGNMENT_RHS | CONDITIONAL_EXPR_CONDITION | CONDITIONAL_EXPR_THEN | CONDITIONAL_EXPR_ELSE | INITIALIZATION_EXPR | INSTANCE_OF_EXPR | MEMBER_REFERENCE_EXPRESSION | MEMBER_SELECT_EXPR | METHODINVOCATION_ARGUMENTS | METHODINVOCATION_METHOD_SELECT | NEW_CLASS_ARGUMENTS | NEW_ARRAY_INIT | NEW_ARRAY_DIMENSION | UNARY_ENCLOSES *0..]-(expr)<-[:ASSERT_CONDITION | DO_WHILE_CONDITION | ENCLOSES_EXPR | FOREACH_EXPR | FORLOOP_CONDITION | HAS_VARIABLEDECL_INIT | IF_CONDITION | SWITCH_EXPR | SYNCHRONIZED_EXPR | THROW_EXPR | WHILE_CONDITION | RETURN_EXPR | CASE_EXPR ]-(assignStat) 
WITH DISTINCT  closeableDec,assignStat,es.uniovi.reflection.codeanalysis.functions.getEnclosingMethod(closeableDec) as method
MATCH (method)-[: CALLABLE_HAS_BODY | CASE_STATEMENTS| CATCH_ENCLOSES_BLOCK| CATCH_PARAM| WHILE_STATEMENT| DO_WHILE_STATEMENT| ENCLOSES| FOREACH_STATEMENT| FOREACH_VAR| FORLOOP_INIT| FORLOOP_STATEMENT| FORLOOP_UPDATE| CALLABLE_HAS_PARAMETER| HAS_VARIABLEDECL_INIT| IF_THEN| IF_ELSE| LABELED_STMT_ENCLOSES| SWITCH_ENCLOSES_CASE| SYNCHRONIZED_ENCLOSES_BLOCK| TRY_BLOCK| TRY_CATCH | TRY_FINALLY| TRY_RESOURCES *]->(stmtBeforeEx)-[exRel:CFG_IF_THERE_IS_UNCAUGHT_EXCEPTION | CFG_MAY_THROW | CFG_THROWS]->(stmtAfterEx) 
WHERE NOT(TYPE(exRel)="CFG_IF_THERE_IS_UNCAUGHT_EXCEPTION" AND stmtBeforeEx:CATCH_BLOCK) 
WITH closeableDec,assignStat,method,stmtBeforeEx,stmtAfterEx
CALL apoc.path.subgraphNodes(stmtBeforeEx,{terminatorNodes:[assignStat],limit:1, minLevel:1, relationshipFilter:'<CFG_NEXT_STATEMENT|<CFG_NEXT_STATEMENT_IF_TRUE|<CFG_NEXT_STATEMENT_IF_FALSE|<CFG_FOR_EACH_HAS_NEXT|<CFG_FOR_EACH_NO_MORE_ELEMENTS|<CFG_NO_EXCEPTION|<CFG_CAUGHT_EXCEPTION|<CFG_AFTER_FINALLY_PREVIOUS_BREAK|<CFG_AFTER_FINALLY_PREVIOUS_CONTINUE|<CFG_SWITCH_CASE_IS_EQUAL_TO|<CFG_SWITCH_DEFAULT_CASE|<CFG_IF_THERE_IS_UNCAUGHT_EXCEPTION|<CFG_MAY_THROW|<CFG_THROWS'}) yield node
MATCH (closeStmt)-[:ASSERT_CONDITION | DO_WHILE_CONDITION | ENCLOSES_EXPR | FOREACH_EXPR | FORLOOP_CONDITION | HAS_VARIABLEDECL_INIT | IF_CONDITION | SWITCH_EXPR | SYNCHRONIZED_EXPR | THROW_EXPR | WHILE_CONDITION | RETURN_EXPR  | CASE_EXPR ]->() -[:ARRAYACCESS_EXPR | ARRAYACCESS_INDEX | ASSIGNMENT_LHS | ASSIGNMENT_RHS | BINOP_LHS | BINOP_RHS | BINOP_COND_RHS | CAST_ENCLOSES | COMPOUND_ASSIGNMENT_LHS | COMPOUND_ASSIGNMENT_RHS | CONDITIONAL_EXPR_CONDITION | CONDITIONAL_EXPR_THEN | CONDITIONAL_EXPR_ELSE | INITIALIZATION_EXPR | INSTANCE_OF_EXPR | MEMBER_REFERENCE_EXPRESSION | MEMBER_SELECT_EXPR | METHODINVOCATION_ARGUMENTS | METHODINVOCATION_METHOD_SELECT | NEW_CLASS_ARGUMENTS | NEW_ARRAY_INIT | NEW_ARRAY_DIMENSION | UNARY_ENCLOSES *0..]->(:METHOD_INVOCATION)-[:METHODINVOCATION_METHOD_SELECT]->(:MEMBER_SELECTION{memberName:'close', actualType: "()void"})-[:MEMBER_SELECT_EXPR]->()<-[:USED_BY]-(closeableDec) 
WITH closeableDec,assignStat,method,stmtBeforeEx,stmtAfterEx,closeStmt
CALL apoc.path.subgraphNodes(closeStmt,{terminatorNodes:[stmtAfterEx],optional:true,limit:1, minLevel:1, relationshipFilter:'<CFG_NEXT_STATEMENT|<CFG_NEXT_STATEMENT_IF_TRUE|<CFG_NEXT_STATEMENT_IF_FALSE|<CFG_FOR_EACH_HAS_NEXT|<CFG_FOR_EACH_NO_MORE_ELEMENTS|<CFG_NO_EXCEPTION|<CFG_CAUGHT_EXCEPTION|<CFG_AFTER_FINALLY_PREVIOUS_BREAK|<CFG_AFTER_FINALLY_PREVIOUS_CONTINUE|<CFG_SWITCH_CASE_IS_EQUAL_TO|<CFG_SWITCH_DEFAULT_CASE|<CFG_IF_THERE_IS_UNCAUGHT_EXCEPTION|<CFG_MAY_THROW|<CFG_THROWS'}) yield node 
WITH closeableDec,assignStat,method,stmtBeforeEx,stmtAfterEx,COLLECT(closeStmt) as closes, ANY(closeAfterEx in COLLECT(NOT node IS NULL) WHERE closeAfterEx) as closeAfterEx
WHERE NOT closeAfterEx
UNWIND closes as closeStmt
CALL apoc.path.subgraphNodes(closeStmt,{terminatorNodes:[stmtBeforeEx],limit:1, minLevel:1, relationshipFilter:'<CFG_NEXT_STATEMENT|<CFG_NEXT_STATEMENT_IF_TRUE|<CFG_NEXT_STATEMENT_IF_FALSE|<CFG_FOR_EACH_HAS_NEXT|<CFG_FOR_EACH_NO_MORE_ELEMENTS|<CFG_NO_EXCEPTION|<CFG_CAUGHT_EXCEPTION|<CFG_AFTER_FINALLY_PREVIOUS_BREAK|<CFG_AFTER_FINALLY_PREVIOUS_CONTINUE|<CFG_SWITCH_CASE_IS_EQUAL_TO|<CFG_SWITCH_DEFAULT_CASE'}) yield node
WITH distinct closeableDec,assignStat,method,closeStmt,stmtBeforeEx ORDER BY closeableDec,stmtBeforeEx.lineNumber
WITH distinct closeableDec,assignStat,method,closeStmt, COLLECT(stmtBeforeEx) as stmtsBeforeEx
MATCH (method)<-[:DECLARES_METHOD | DECLARES_CONSTRUCTOR]-(enclClass:TYPE_DEFINITION)<-[:HAS_TYPE_DEF| HAS_INNER_DEF]-(cu:COMPILATION_UNIT) 
RETURN DISTINCT '{"rule":"CMU-ERR54","location":"'+cu.fileName+'","node":"LOCAL VAR '+closeableDec.actualType+' '+closeableDec.name+'","line":"'+closeableDec.lineNumber+'","column":"'+closeableDec.column+'","message":"Variable ' + closeableDec.name + '(defined in line' + closeableDec.lineNumber + ', method ' + method.name + ', class ' + enclClass.fullyQualifiedName + '; and initialized in line ' + assignStat.lineNumber +') might not be properly closed in line ' + closeStmt.lineNumber + ', as statement(s) (in lines ' + REDUCE(seed='',prev IN stmtsBeforeEx | seed+prev.lineNumber + ',') + ') may throw an exception."}'