Actions: Fix bad performance in getTargetPath

[tausbn]

Seen on github/codeql, some queries had very poor performance:

 [2/24 eval 36m4s] Evaluation done; writing results to codeql/actions-queries/Security/CWE-312/ExcessiveSecretsExposure.bqrs

Investigating further lead to the following worrying sequence of joins (after I ran out of patience and cancelled the query):

[2025-04-01 12:31:03] Tuple counts for Yaml::YamlInclude.getTargetPath/0#dispred#32565107#fb#reorder_1_0/2@i6#9f4b2jw1 after 8m40s:
...
    559418    ~33%        {1} r5 = SCAN `Yaml::YamlNode.getLocation/0#dispred#24555c57#prev_delta` OUTPUT In.1
...
    909345525 ~821%       {3} r7 = JOIN r5 WITH `Yaml::YamlNode.getLocation/0#dispred#24555c57#prev` CARTESIAN PRODUCT OUTPUT Rhs.1, Lhs.0 'result', Rhs.0
    909342139 ~779%       {3}    | JOIN WITH `Locations::Location.getFile/0#dispred#dcf38c8d#prev` ON FIRST 1 OUTPUT Rhs.1, Lhs.1 'result', Lhs.2
    909338753 ~794%       {3}    | JOIN WITH containerparent_10#join_rhs ON FIRST 1 OUTPUT Rhs.1, Lhs.1 'result', Lhs.2
    909335367 ~824%       {3}    | JOIN WITH `FileSystem::Container.getAbsolutePath/0#dispred#d234e6fa` ON FIRST 1 OUTPUT Lhs.2, Lhs.1 'result', Rhs.1
    883246724 ~812%       {3}    | JOIN WITH `Yaml::YamlNode.getDocument/0#dispred#ee1eb3bf#bf_10#join_rhs` ON FIRST 1 OUTPUT Rhs.1 'this', Lhs.1 'result', Lhs.2
    760047185 ~838%       {5}    | JOIN WITH yaml_scalars ON FIRST 1 OUTPUT Lhs.1 'result', Lhs.0 'this', Rhs.2, _, Lhs.2
    0         ~0%         {4}    | REWRITE WITH Tmp.3 := "/", Out.3 := (In.4 ++ Tmp.3 ++ InOut.2), TEST Out.3 = InOut.0 KEEPING 4
                          {4}    | REWRITE WITH NOT [TEST InOut.2 startsWith "/"]
...

The culprit turned out to be the following method on class YamlInclude

private string getTargetPath() {
    exists(string path | path = this.getValue() |
    if path.matches("/%")
    then result = path
    else
        result = this.getDocument().getLocation().getFile().getParentContainer().getAbsolutePath() 
            + "/" + path
    )
}

Basically, in the else branch, the evaluator was producing all possible values of result before filtering out the ones where the path component started with a forward slash.

To fix this, I opted to factor out the logic into two helper predicates, each accounting for whether this.getValue() does or does not start with a /. With this, evaluating the original query from a clean cache takes roughly 3.3s.

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[adityasharad]

Nice work, and makes sense. Just one question.

[adityasharad]

Considering a change note, but I think I'd rather attach one to the extractor change.