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nulls enabled - null value in a struct in an array - exception

Community Beginner ,
Mar 28, 2022 Mar 28, 2022

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In CF2021, an expression of the form

  somevar[1].x

throws an exception when the value of x is null. This happens even when trying to test for null like IsNull(somevar[1].x)

 

There's no similar problem with somevar[1][1] or somevar.x.x or somevar.x[1] or even somevar[1][1].x.x[1].x[1].x.x.x as long as the variable and its contents have the appropriate types, and no problem with somevar[1].x when the x in the struct in the array is not null.

 

I tried many variations and the exception is thrown only in these specific circumstances: the next-to-last operation is an array element lookup, the last operation is a struct member lookup, and the value found in the struct is null.

 

If the array access and struct access are separated from each other by the use of a temporary variable, the exception doesn't happen.

 

The exception message is "Element X is undefined in a CFML structure referenced as part of an expression."

 

Here's a demo of the exception-throwing case, along with all the similar non-exception-throwing ones.

<cfscript>
/* Part 1: Array containing an array containing a null */
test_aan = [ [ null ] ];                                   /* set it */
v = test_aan[1][1];                                        /* get it */
WriteDump({test: "aan", v: v, v_is_null: IsNull(v)});      /* show it */

/* Part 2: Struct containing a struct containing a null */
test_ssn = { x: { x: null } };                             /* set it */
v = test_ssn.x.x;                                          /* get it */
WriteDump({test: "ssn", v: v, v_is_null: IsNull(v)});      /* show it */

/* Part 3: Struct containing an array containing a null */
test_san = { x: [ null ] };                                /* set it */
v = test_san.x[1];                                         /* get it */
WriteDump({test: "san", v: v, v_is_null: IsNull(v)});      /* show it */

/* Part 4: Array containing a struct containing a number */
test_asi = [ { x: 1 } ];                                   /* set it */
v = test_asi[1].x;                                         /* get it */
WriteDump({test: "asi", v: v, v_is_null: IsNull(v)});      /* show it */

/* Part 5: Array containing a struct containing a null */
test_asn = [ { x: null } ];                                /* set it */
tmp = test_asn[1];                                         /* use tmp */
v = tmp.x;                                                 /* get it */
WriteDump({test: "asntmp", v: v, v_is_null: IsNull(v)});   /* show it */

/* Part 6: Array containing a struct containing a null 
   (try without a tmp variable - throws exception) */
test_asn = [ { x: null } ];                                /* set it */
v = test_asn[1].x;                                         /* get it */
WriteDump({test: "asn", v: v, v_is_null: IsNull(v)});      /* show it */
</cfscript>

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Community Expert ,
Mar 30, 2022 Mar 30, 2022

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You are right. There is inconsistency: Part 5 works, and Part 6 gives an error. Whereas we would expect them to have the same result.

 

If I were you I would report a bug.

 

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New Here ,
Mar 30, 2022 Mar 30, 2022

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This is now CF-4212947

(I am the original poster. My display name changed because accounts got merged when I logged into the bug tracker.)

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Community Expert ,
Apr 01, 2022 Apr 01, 2022

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Thanks for posting and for sharing the link.

I have voted to get the bug fixed.

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