[MNG-8350] Improve storage and computation of locations in model objects

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 4.0.0-beta-5
• Fix Version/s: 4.0.0-rc-1
• Assignee: Guillaume Nodet
• Reporter: Guillaume Nodet
• Created: 24/Oct/24 07:03
• Updated: 24/Oct/24 14:37
• Resolved: 24/Oct/24 14:37

Description

The Build constructor has the following code:

        Map<Object, InputLocation> newlocs = builder.locations != null ? builder.locations : Collections.emptyMap();
        Map<Object, InputLocation> oldlocs = builder.base != null && builder.base.locations != null ? builder.base.locations : Collections.emptyMap();
        Map<Object, InputLocation> mutableLocations = new HashMap<>(super.locations);
        mutableLocations.put("sourceDirectory", newlocs.containsKey("sourceDirectory") ? newlocs.get("sourceDirectory") : oldlocs.get("sourceDirectory"));
        mutableLocations.put("scriptSourceDirectory", newlocs.containsKey("scriptSourceDirectory") ? newlocs.get("scriptSourceDirectory") : oldlocs.get("scriptSourceDirectory"));
        mutableLocations.put("testSourceDirectory", newlocs.containsKey("testSourceDirectory") ? newlocs.get("testSourceDirectory") : oldlocs.get("testSourceDirectory"));
        mutableLocations.put("outputDirectory", newlocs.containsKey("outputDirectory") ? newlocs.get("outputDirectory") : oldlocs.get("outputDirectory"));
        mutableLocations.put("testOutputDirectory", newlocs.containsKey("testOutputDirectory") ? newlocs.get("testOutputDirectory") : oldlocs.get("testOutputDirectory"));
        mutableLocations.put("extensions", newlocs.containsKey("extensions") ? newlocs.get("extensions") : oldlocs.get("extensions"));
        this.locations = Collections.unmodifiableMap(mutableLocations);

This is inefficient, especially when building models programmatically, in which cases locations are usually not set. The code will always store a null value for each key, whereas an empty map could be sufficient if there's no actual values.

The generator code is located at:
https://github.com/apache/maven/blob/b370e5e9299813e6df483bac049ec162b86fb7e8/src/mdo/model.vm#L174-L186

Issue Links

• links to: GitHub Pull Request #1847