| | 140 | ==== There Must Be No Uninitialised Local Variables ==== |
| | 141 | * '''Symbolic Name in XML Configuration''': checkNoUninitialisedLocalVariables |
| | 142 | * '''Dependant Tags in XML Configuration''': - |
| | 143 | |
| | 144 | This check makes sure there are no uninitialised local variables. This covers local variables declared within statement blocks or module control parts. Variables declared within components are not considered as they may or may not be initialised depending on which other behaviour constructs have been executed. Instead, the data flow analysis is performed strictly within the scope of the top-level statement block. In the following example, the state of the various variables declared within a function is described for each statement using comments directly above the statement. |
| | 145 | |
| | 146 | {{{ |
| | 147 | function f_ConditionalSpec() { |
| | 148 | var integer v_s0; |
| | 149 | var integer v_s1; |
| | 150 | var integer v_s2 := 1; |
| | 151 | var integer v_s3; |
| | 152 | var integer v_s4; |
| | 153 | var integer v_s5; |
| | 154 | |
| | 155 | //v_s2 is initialised upon declaration -> no warning |
| | 156 | if (v_s2 == 1) { |
| | 157 | //v_s3 is not initialised -> warning |
| | 158 | //v_s0 initialised within the conditional after this statement |
| | 159 | v_s0 := v_s3 + 1; |
| | 160 | |
| | 161 | //v_s1 is not initialised -> warning |
| | 162 | //v_s2 is initialised -> no warning |
| | 163 | //v_s3 initialised within the conditional after this statement |
| | 164 | v_s3 := v_s2 + 1 + v_s1; |
| | 165 | |
| | 166 | //v_s3 is initialised above -> no warning |
| | 167 | //v_s4 initialised within the conditional after this statement |
| | 168 | v_s4 := v_s3 + 1; |
| | 169 | } else { |
| | 170 | //v_s2 is initialised -> no warning |
| | 171 | //v_s4 initialised within the else branch after this statement |
| | 172 | v_s4 := v_s2 + 1; |
| | 173 | } |
| | 174 | |
| | 175 | //v_s3 is only initialised within one of the possible paths -> warning |
| | 176 | //v_s4 is initialised within both possible paths (within all branches of the conditional above) -> no warning |
| | 177 | v_s5 := v_s3 + v_s4; |
| | 178 | } |
| | 179 | }}} |
| | 180 | |
| | 181 | For variables initialised within branching behaviour, such as if-else if-else constructs, alt statements, and call statements, the data flow analysis evaluates whether each branch directly initialises the variables with absolute certainty. If the variable is initialised in only some of the branches, then a warning is raised as it cannot be ensured that a variable will be initialised before use during execution. This also applies to nested branches. For loops, it cannot be ensured that a variable will be initialised as a loop can be skipped if the loop condition evaluates to false. In such case, variables initialised within the loop are considered as such in the subsequent statements within the loop, however, for statements outside the loop, the variable is still considered to be not initialised (unless there is explicit initialisation outside the loop). |
| | 182 | |
