bug(#743): optimized duplicated-names-in-diff-context with for-each-group (#778)

* bug(#743): optimize duplicate names detection using xsl:for-each-group and update test cases

* bug(#743): add yamllint disable rule for line-length in test YAML files

* bug(#743): add test case for duplicate names detection in deep hierarchy

* bug(#743): update duplicate names test case to reflect new line numbers and object names

Author: h1alexbel

src/main/resources/org/eolang/lints/misc/duplicate-names-in-diff-context.xsl

@@ -10,9 +10,8 @@
   <xsl:output encoding="UTF-8" method="xml"/>
   <xsl:template match="/">
     <defects>
-      <xsl:for-each select="//o[not(ancestor::o[eo:test-attr(.)]) and not(eo:special(@name)) and not(@base='∅')]">
-        <xsl:variable name="namesakes" select="//o[not(ancestor::o[eo:test-attr(.)]) and @name=current()/@name and not(@base='∅')]"/>
-        <xsl:if test="count($namesakes)&gt;1">
+      <xsl:for-each-group select="//o[not(ancestor::o[eo:test-attr(.)]) and not(eo:special(@name)) and not(@base='∅')]" group-by="@name">
+        <xsl:if test="count(current-group())&gt;1">
           <defect>
             <xsl:variable name="line" select="eo:lineno(@line)"/>
             <xsl:attribute name="line">
@@ -27,8 +26,8 @@
             <xsl:text>Object "</xsl:text>
             <xsl:value-of select="@name"/>
             <xsl:text>" has the same name as </xsl:text>
-            <xsl:variable name="lines" select="$namesakes[@line and (not(current()/@line) or @line != current()/@line)]/@line"/>
-            <xsl:variable name="empty" select="count($lines) != count($namesakes) - 1"/>
+            <xsl:variable name="lines" select="current-group()/@line[. and . != current()/@line]"/>
+            <xsl:variable name="empty" select="count($lines) != count(current-group()) - 1"/>
             <xsl:if test="count($lines) &gt; 0">
               <xsl:text>the objects on the lines </xsl:text>
               <xsl:value-of select="string-join($lines, ', ')"/>
@@ -41,7 +40,7 @@
             </xsl:if>
           </defect>
         </xsl:if>
-      </xsl:for-each>
+      </xsl:for-each-group>
     </defects>
   </xsl:template>
 </xsl:stylesheet>

src/test/resources/org/eolang/lints/packs/single/duplicate-names-in-diff-context/catches-duplicate-names-in-diff-context.yaml

@@ -4,8 +4,8 @@
 sheets:
   - /org/eolang/lints/misc/duplicate-names-in-diff-context.xsl
 asserts:
-  - /defects/defect[@line='4' or @line='6']
-  - /defects[count(defect[@severity='warning'])=2]
+  - /defects[count(defect[@severity='warning'])=1]
+  - /defects/defect[@line='4']
 input: |
   # No comments.
   [] > foo

src/test/resources/org/eolang/lints/packs/single/duplicate-names-in-diff-context/catches-duplicated-names-in-deep-hierarchy.yaml

@@ -0,0 +1,22 @@
+# SPDX-FileCopyrightText: Copyright (c) 2016-2025 Objectionary.com
+# SPDX-License-Identifier: MIT
+---
+# yamllint disable rule:line-length
+sheets:
+  - /org/eolang/lints/misc/duplicate-names-in-diff-context.xsl
+asserts:
+  - /defects[count(defect[@severity='warning'])=1]
+  - /defects/defect[@line='5']
+  - /defects/defect[normalize-space()='Object "s" has the same name as the objects on the lines 11']
+input: |
+  # No comments.
+  [] > head
+    [] > first
+      [] > second
+        "plus" > s
+        [] > third
+          [] > fourth
+            [] > nested
+              [] > more-nested
+                [] > tail
+                  "boom" > s

src/test/resources/org/eolang/lints/packs/single/duplicate-names-in-diff-context/catches-duplicated-names-on-multiple-lines.yaml

@@ -0,0 +1,21 @@
+# SPDX-FileCopyrightText: Copyright (c) 2016-2025 Objectionary.com
+# SPDX-License-Identifier: MIT
+---
+# yamllint disable rule:line-length
+sheets:
+  - /org/eolang/lints/misc/duplicate-names-in-diff-context.xsl
+asserts:
+  - /defects[count(defect[@severity='warning'])=1]
+  - /defects/defect[@line='4']
+  - /defects/defect[normalize-space()='Object "hello" has the same name as the objects on the lines 6, 8, 10']
+input: |
+  # No comments.
+  [] > main
+    [] > f1
+      "Hello world" > hello
+    [] > f2
+      "Привет мир" > hello
+    [] > f3
+      "你好，世界" > hello
+    [] > f4
+      "こんにちは、世界" > hello

src/test/resources/org/eolang/lints/packs/single/duplicate-names-in-diff-context/catches-duplicates-except-in-tests.yaml

@@ -5,10 +5,8 @@
 sheets:
   - /org/eolang/lints/misc/duplicate-names-in-diff-context.xsl
 asserts:
-  - /defects[count(defect[@severity='warning'])=2]
+  - /defects[count(defect[@severity='warning'])=1]
   - /defects/defect[@line='4']
-  - /defects/defect[@line='6']
-  - /defects/defect[contains(normalize-space(), 'has the same name as the objects on the lines 4')]
   - /defects/defect[contains(normalize-space(), 'has the same name as the objects on the lines 6')]
 input: |
   # Foo.

src/test/resources/org/eolang/lints/packs/single/duplicate-names-in-diff-context/catches-multiple-name-groups.yaml

@@ -0,0 +1,23 @@
+# SPDX-FileCopyrightText: Copyright (c) 2016-2025 Objectionary.com
+# SPDX-License-Identifier: MIT
+---
+# yamllint disable rule:line-length
+sheets:
+  - /org/eolang/lints/misc/duplicate-names-in-diff-context.xsl
+asserts:
+  - /defects[count(defect[@severity='warning'])=2]
+  - /defects/defect[@line='4']
+  - /defects/defect[@line='8']
+  - /defects/defect[normalize-space()='Object "foo" has the same name as the objects on the lines 6']
+  - /defects/defect[normalize-space()='Object "arc" has the same name as the objects on the lines 10']
+input: |
+  # No comments.
+  [] > app
+    [] > f1
+      42 > foo
+    [] > f2
+      33 > foo
+    [] > f3
+      -8819 > arc
+    [] > f4
+      -1 > arc

src/test/resources/org/eolang/lints/packs/single/duplicate-names-in-diff-context/prints-context-when-lines-empty.yaml

@@ -4,7 +4,7 @@
 sheets:
   - /org/eolang/lints/misc/duplicate-names-in-diff-context.xsl
 asserts:
-  - /defects[count(defect[@context and @severity='warning'])=2]
+  - /defects[count(defect[@context and @severity='warning'])=1]
 document: |
   <object author="tests">
     <o>