feat(#1271): run Java lints from YAML packs via lint key

src/test/java/org/eolang/lints/LtByXslTest.java

@@ -108,6 +108,10 @@ void lintsInMultipleThreads() {
     @ParameterizedTest
     @ClasspathSource(value = "org/eolang/lints/packs/single/", glob = "**.yaml")
     void testsAllLintsByEo(final String yaml, final String pack) {
+        org.junit.jupiter.api.Assumptions.assumeTrue(
+            !((Map<?, ?>) new org.yaml.snakeyaml.Yaml().load(yaml)).containsKey("lint"),
+            String.format("Pack '%s' is a Java lint pack", pack)
+        );
         MatcherAssert.assertThat(
             String.format(
                 "Pack '%s' doesn't tell the story as expected",
@@ -125,6 +129,32 @@ void testsAllLintsByEo(final String yaml, final String pack) {
         );
     }
 
+    @SuppressWarnings("JTCOP.RuleNotContainsTestWord")
+    @Execution(ExecutionMode.CONCURRENT)
+    @ParameterizedTest
+    @ClasspathSource(value = "org/eolang/lints/packs/single/", glob = "**.yaml")
+    void testsAllLintsByLintName(final String yaml, final String pack) {
+        org.junit.jupiter.api.Assumptions.assumeTrue(
+            ((Map<?, ?>) new org.yaml.snakeyaml.Yaml().load(yaml)).containsKey("lint"),
+            String.format("Pack '%s' has no lint key", pack)
+        );
+        MatcherAssert.assertThat(
+            String.format(
+                "Pack '%s' doesn't tell the story as expected",
+                pack
+            ),
+            new fixtures.XtDefects(
+                new XtSticky(
+                    new XtLint(
+                        yaml,
+                        eo -> new EoProgram(pack, new InputOf(eo)).parse()
+                    )
+                )
+            ),
+            new XtoryMatcher(new DefectsMatcher())
+        );
+    }
+
     @Test
     void returnsMotive() throws Exception {
         MatcherAssert.assertThat(
@@ -480,22 +510,31 @@ private static Predicate<Path> yamls() {
      */
     @SuppressWarnings("StreamResourceLeak")
     private static boolean hasMatchingXsl(final Path yaml) {
+        final boolean result;
         try {
-            return Files.walk(Paths.get("src/main/resources/org/eolang/lints"))
-                .filter(Files::isRegularFile)
-                .filter(path -> path.toString().endsWith(".xsl"))
-                .map(path -> path.getParent().getFileName().toString()).anyMatch(
-                    group -> Files.exists(
-                        Paths.get("src/main/resources/org/eolang/lints/").resolve(group).resolve(
-                            String.format(
-                                "%s.xsl",
-                                yaml.getParent().getFileName().toString()
-                            )
+            if (((Map<?, ?>) new org.yaml.snakeyaml.Yaml().load(
+                new String(Files.readAllBytes(yaml), java.nio.charset.StandardCharsets.UTF_8)
+            )).containsKey("lint")) {
+                result = true;
+            } else {
+                result = Files.walk(Paths.get("src/main/resources/org/eolang/lints"))
+                    .filter(Files::isRegularFile)
+                    .filter(path -> path.toString().endsWith(".xsl"))
+                    .map(path -> path.getParent().getFileName().toString()).anyMatch(
+                        group -> Files.exists(
+                            Paths.get("src/main/resources/org/eolang/lints/")
+                                .resolve(group).resolve(
+                                    String.format(
+                                        "%s.xsl",
+                                        yaml.getParent().getFileName().toString()
+                                    )
+                                )
                         )
-                    )
-                );
+                    );
+            }
         } catch (final IOException ex) {
             throw new IllegalStateException(ex);
         }
+        return result;
     }
 }

src/test/java/org/eolang/lints/XtLint.java

@@ -0,0 +1,123 @@
+/*
+ * SPDX-FileCopyrightText: Copyright (c) 2016-2026 Objectionary.com
+ * SPDX-License-Identifier: MIT
+ */
+package org.eolang.lints;
+
+import com.jcabi.xml.XML;
+import com.yegor256.xsline.Shift;
+import com.yegor256.xsline.Xsline;
+import java.io.IOException;
+import java.util.Collection;
+import java.util.Map;
+import org.eolang.xax.Xtory;
+import org.xembly.Directives;
+import org.xembly.Xembler;
+
+/**
+ * A story that runs a Java-implemented lint by its name.
+ * Reads the {@code lint} key from the pack YAML and applies
+ * the resolved {@link Lint} to the input, producing a
+ * {@code <defects>} document.
+ * @since 1.0
+ */
+public final class XtLint implements Xtory {
+
+    /**
+     * Original story.
+     */
+    private final Xtory origin;
+
+    /**
+     * Ctor.
+     * @param yaml YAML pack
+     * @param parser Parser
+     */
+    public XtLint(final String yaml, final Xtory.Parser parser) {
+        this(new org.eolang.xax.XtYaml(yaml, parser));
+    }
+
+    /**
+     * Ctor.
+     * @param origin Original story
+     */
+    private XtLint(final Xtory origin) {
+        this.origin = origin;
+    }
+
+    @Override
+    public Map<String, Object> map() {
+        return this.origin.map();
+    }
+
+    @Override
+    public XML before() {
+        return this.origin.before();
+    }
+
+    @Override
+    public XML after() {
+        return this.xsline().pass(this.before());
+    }
+
+    @Override
+    public Xsline xsline() {
+        return new Xsline(
+            new Shift() {
+                @Override
+                public String uid() {
+                    return XtLint.this.name();
+                }
+
+                @Override
+                public XML apply(final int position, final XML xml) {
+                    return XtLint.this.defects(xml);
+                }
+            }
+        );
+    }
+
+    @Override
+    public Collection<String> asserts() {
+        return this.origin.asserts();
+    }
+
+    /**
+     * Lint name from the YAML map.
+     * @return Lint name
+     */
+    private String name() {
+        return String.valueOf(this.origin.map().get("lint"));
+    }
+
+    /**
+     * Run the lint and serialize defects into XML.
+     * @param xml Input XMIR
+     * @return Defects document
+     */
+    private XML defects(final XML xml) {
+        final Directives dirs = new Directives().add("defects");
+        try {
+            for (final Lint lint : new PkMono()) {
+                if (lint.name().equals(this.name())) {
+                    for (final Defect defect : lint.defects(xml)) {
+                        dirs.add("defect")
+                            .attr("line", defect.line())
+                            .attr("severity", defect.severity().mnemo())
+                            .set(defect.text())
+                            .up();
+                    }
+                    break;
+                }
+            }
+        } catch (final IOException ex) {
+            throw new IllegalStateException(
+                String.format("Failed to run lint %s", this.name()),
+                ex
+            );
+        }
+        return new com.jcabi.xml.XMLDocument(
+            new Xembler(dirs).xmlQuietly()
+        );
+    }
+}

src/test/resources/org/eolang/lints/packs/single/ascii-only/catches-cyrillic-comment.yaml

@@ -0,0 +1,12 @@
+# SPDX-FileCopyrightText: Copyright (c) 2016-2026 Objectionary.com
+# SPDX-License-Identifier: MIT
+---
+lint: ascii-only
+asserts:
+  - /defects[count(defect[@severity='warning'])=1]
+document: |
+  <object author="tests">
+    <comments>
+      <comment line="1">привет</comment>
+    </comments>
+  </object>

src/test/resources/org/eolang/lints/packs/single/incorrect-unlint/catches-unknown-lint.yaml

@@ -0,0 +1,16 @@
+# SPDX-FileCopyrightText: Copyright (c) 2016-2026 Objectionary.com
+# SPDX-License-Identifier: MIT
+---
+lint: incorrect-unlint
+asserts:
+  - /defects[count(defect[@severity='error'])=1]
+document: |
+  <object author="tests">
+    <metas>
+      <meta line="1">
+        <head>unlint</head>
+        <tail>non-existent-lint-name:5</tail>
+      </meta>
+    </metas>
+    <o line="3" name="foo"/>
+  </object>

src/test/resources/org/eolang/lints/packs/single/reserved-name/allows-custom-name.yaml

@@ -0,0 +1,12 @@
+# SPDX-FileCopyrightText: Copyright (c) 2016-2026 Objectionary.com
+# SPDX-License-Identifier: MIT
+---
+lint: reserved-name
+asserts:
+  - /defects[count(defect)=0]
+document: |
+  <object author="tests">
+    <o line="1" name="main">
+      <o line="2" name="my-object" base="Φ.foo"/>
+    </o>
+  </object>

src/test/resources/org/eolang/lints/packs/single/syntax-version/allows-older-syntax.yaml

@@ -0,0 +1,16 @@
+# SPDX-FileCopyrightText: Copyright (c) 2016-2026 Objectionary.com
+# SPDX-License-Identifier: MIT
+---
+lint: syntax-version
+asserts:
+  - /defects[count(defect)=0]
+document: |
+  <object author="tests" version="0.0.1">
+    <metas>
+      <meta line="1">
+        <head>syntax</head>
+        <tail>0.0.1</tail>
+      </meta>
+    </metas>
+    <o line="3" name="foo"/>
+  </object>

src/test/resources/org/eolang/lints/packs/single/syntax-version/catches-newer-syntax.yaml

@@ -0,0 +1,16 @@
+# SPDX-FileCopyrightText: Copyright (c) 2016-2026 Objectionary.com
+# SPDX-License-Identifier: MIT
+---
+lint: syntax-version
+asserts:
+  - /defects[count(defect[@severity='error'])=1]
+document: |
+  <object author="tests" version="0.0.1">
+    <metas>
+      <meta line="1">
+        <head>syntax</head>
+        <tail>999.0.0</tail>
+      </meta>
+    </metas>
+    <o line="3" name="foo"/>
+  </object>