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fix: handle missing template files gracefully #2437

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fix: handle missing template files gracefully #2437

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6 changes: 5 additions & 1 deletion src/main/java/dev/jbang/source/RefTarget.java
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Original file line number Diff line number Diff line change
Expand Up @@ -86,7 +86,11 @@ public String toString() {
}

public static RefTarget create(String ref, Path dest, ResourceResolver siblingResolver) {
return new RefTarget(siblingResolver.resolve(ref), dest);
ResourceRef resolved = siblingResolver.resolve(ref);
if (resolved == null) {
resolved = ResourceRef.forUnresolvable(ref, "not resolvable from " + siblingResolver.description());
}
return new RefTarget(resolved, dest);
}

public static RefTarget create(ResourceRef ref, Path dest) {
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21 changes: 21 additions & 0 deletions src/test/java/dev/jbang/cli/TestInit.java
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Original file line number Diff line number Diff line change
Expand Up @@ -354,4 +354,25 @@

}

@Test
void testInitWithMissingTemplateFile() throws IOException {
Path cwd = Util.getCwd();
Path out = cwd.resolve("result.java");

// Create template with reference to non-existent file
int addResult = JBang.getCommandLine()
.execute("template", "add", "-f", cwd.toString(), "--name=bad-template",
"{basename}/{basename}App.java=tpl/NonExistentFile.java");
assertThat(addResult, is(0));

Check failure on line 366 in src/test/java/dev/jbang/cli/TestInit.java

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GitHub Actions / ci-build / unit-test-jvm (ubuntu-latest)

TestInit.testInitWithMissingTemplateFile() 

java.lang.AssertionError: 
Expected: is <0>
     but: was <2>

Check failure on line 366 in src/test/java/dev/jbang/cli/TestInit.java

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GitHub Actions / ci-build / unit-test-jvm (macos-latest)

TestInit.testInitWithMissingTemplateFile() 

java.lang.AssertionError: 
Expected: is <0>
     but: was <2>

// Attempting to init with this template should fail gracefully with clear error
int result = JBang.getCommandLine()
.execute("init", "--template=bad-template", "test");

// Should fail with non-zero exit code
assertThat(result, not(0));
Comment on lines +369 to +373
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Copilot AI Apr 2, 2026

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The test comment says the init should fail “with clear error”, but the test only checks for a non-zero exit code. To ensure this change prevents the prior NPE regression, capture stderr/stdout and assert that it contains the new unresolvable-resource message (and/or does not contain the previous NullPointerException text). BaseTest already provides helpers like captureOutput(...)/checkedRun(...) that can be used here.

Suggested change
int result = JBang.getCommandLine()
.execute("init", "--template=bad-template", "test");
// Should fail with non-zero exit code
assertThat(result, not(0));
int[] result = new int[1];
String output = captureOutput(() -> result[0] = JBang.getCommandLine()
.execute("init", "--template=bad-template", "test"));
// Should fail with non-zero exit code
assertThat(result[0], not(0));
assertThat(output, containsString("unresolvable"));
assertThat(output, containsString("NonExistentFile.java"));
assertThat(output, not(containsString("NullPointerException")));

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// Output file should not be created
assertThat(out.toFile().exists(), is(false));
Comment on lines +359 to +375
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Copilot AI Apr 2, 2026

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The test currently asserts result.java is not created, but jbang init --template=bad-template test won’t write to result.java anyway (it will generate files based on the template’s target pattern, likely under cwd/test/...). This means the “no output files are created” assertion is not actually validating the behavior. Consider asserting that the expected generated directory/file for the template target (eg cwd.resolve("test") or the specific {basename}/{basename}App.java output) does not exist after the failing init.

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}

}
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