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Unset config properties: System.getProperty should return default value or null #10013

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merged 2 commits into from
Feb 18, 2025
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Unset config properties: System.getProperty should return default value or null #10013

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4a64e9d
Unset config properties: use default value or fail with meaningful ex…
zbynek Oct 18, 2024
f1184a6
Return null if default is neither set in xml or provided as argument
zbynek Feb 14, 2025
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10 changes: 9 additions & 1 deletion dev/core/src/com/google/gwt/dev/jjs/impl/ResolvePermutationDependentValues.java
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Original file line number Diff line number Diff line change
Expand Up @@ -47,6 +47,7 @@
import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Set;

/**
Expand Down Expand Up @@ -76,7 +77,14 @@ public void endVisit(JPermutationDependentValue x, Context ctx) {
private JExpression propertyValueExpression(JPermutationDependentValue x) {
List<String> propertyValues = props.getConfigurationProperties().getStrings(x.getRequestedValue());

String propertyValue = propertyValues.isEmpty() ? null : Joiner.on(",").join(propertyValues);
if (!propertyValues.isEmpty() && propertyValues.stream().allMatch(Objects::isNull)) {
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@niloc132 niloc132 Nov 8, 2024

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I struggle with this distinction every time I try to get back into this code and clean it up - could you add a comment here explaining why we sometimes get [] and sometimes [null]? I think it is signalling (badly, incompletely) that this config property is only permitted to have a single value, but there is no distinction here between "multi-valued with one value" and "single valued and set", so I'm not sure why it matters... Also there is no distinction between "multivalued and unset" and "undefined key", which seems even more egregious.

At least if we keep that confusing behavior, a comment would help to clarify as to why we even do it this way.

if (x.getDefaultValueExpression() != null) {
return x.getDefaultValueExpression();
}
throw new InternalCompilerException("No default set for configuration property '"
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@niloc132 niloc132 Nov 8, 2024

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Do we want to throw here? What about letting the value be null - that's what would happen for java if a system property was unset?

That said, this could also be a follow-up feature after the bug is fixed.

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@zbynek zbynek Nov 8, 2024

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From #9806 (comment) I assumed that defining a config property without a default is bad and should result in a build failure. That's also why I filed gwtproject/gwt-safehtml#31 . I'm OK with changing the behavior and returning null. @jnehlmeier thoughts?

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@niloc132 niloc132 Nov 9, 2024

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If it is an internal compiler error I guess I just don't like it to happen under normal circumstances for a user who either
a) was expecting System.getProperty(name) to return null
b) forgot to pass a default as the second arg to Sysmte.getProperty
c) forgot to set the config property value

Any/all of those seem like a reasonable expectations to have - and you shouldn't be rewarded with an InternalCompilerException if you fail that. Plus, if you hit one ICE, that's the end of compilation, but we in theory could have several errors we could pick up here. ICE does have the advantage that it gives you very clear context about where the error happened - but we have the SourceInfo instance here and can log something helpful?

JsInteropRestrictionChecker is a pretty good example of "I need to log a fatal error for the developer to consume, and a stack trace will never help them figure it out".

If the user did make mistake A or B above, then logging an error will help them figure it out. C wouldn't be as helpful, but the text of the message can be clear that they just need to define a value in the .gwt.xml (or command line, -setProperty foo=bar).

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@jnehlmeier jnehlmeier Feb 12, 2025

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See here: #9806 (comment)

+ x.getRequestedValue() + "'");
}
String propertyValue = propertyValues.isEmpty() ? null : Joiner.on(",").skipNulls().join(propertyValues);
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@niloc132 niloc132 Nov 9, 2024

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 /home/runner/work/gwt/gwt/gwt/dev/core/src/com/google/gwt/dev/jjs/impl/ResolvePermutationDependentValues.java:78:0: warning: Line is longer than 100 characters (found 105). (com.puppycrawl.tools.checkstyle.checks.sizes.LineLengthCheck)
/home/runner/work/gwt/gwt/gwt/dev/core/src/com/google/gwt/dev/jjs/impl/ResolvePermutationDependentValues.java:87:0: warning: Line is longer than 100 characters (found 111). (com.puppycrawl.tools.checkstyle.checks.sizes.LineLengthCheck)

If I'm reading right the first is outside of your patch so ignore.


if (propertyValue != null) {
// It is a configuration property.
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1 change: 1 addition & 0 deletions user/test/com/google/gwt/dev/jjs/SystemGetPropertyTest.gwt.xml
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Expand Up @@ -33,4 +33,5 @@
<set-property name="someOtherDynamicProperty" value="blue">
<when-property-is name="collapsedProperty" value="two"/>
</set-property>
<define-configuration-property name="configPropertyUnset" is-multi-valued="false"/>
</module>
1 change: 1 addition & 0 deletions user/test/com/google/gwt/dev/jjs/test/SystemGetPropertyTest.java
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Expand Up @@ -36,5 +36,6 @@ public void testBindingProperties() {
String expectedResult = "safari".equals(System.getProperty("user.agent")) ?
"InSafari" : "NotInSafari";
assertEquals(expectedResult, System.getProperty("someDynamicProperty"));
assertEquals("foo", System.getProperty("configPropertyUnset", "foo"));
}
}