Fix/MultiFile pattern (Issue #696) by Pr0metheus2 · Pull Request #697 · LogExperts/LogExpert

Pr0metheus2 · 2026-08-26T10:25:34Z

This is a fix for #696

Fixed/MultiFile rollover patterns with an index before the extension:
- RolloverFilenameBuilder: the parser was dropping literal text after the final placeholder, including .log.
- *$J(.).log now correctly expands: app.log → app.1.log → app.2.log.
Updated MultiFile mask dialog legend:
- Fixed incorrectly displayed <date> and <prefix> placeholders in English and German resources.
- Added both usage examples:
  - *$J(.) → app.log, app.log.1, app.log.2
  - *$J(.).log → app.log, app.1.log, app.2.log
- Added the examples in English, German, and Chinese.
- Enlarged the dialog and syntax-help label so the date-format lines are no longer clipped.

Before

After

Fixed/Items in menu File/Multifile -> "Enable MultiFile" and "File name mask...", were always greyed out. Now they are displayed normally after the .log file is open.
- removed the BackColor and ForeColor assignments for both:
  - multiFileEnabledStripMenuItem
  - multifileMaskToolStripMenuItem

Before

After

Added regression coverage:
- Filename-builder tests for app.1.log and app.2.log.
- Reader-level test that loads app.log, app.1.log, and app.2.log in correct order using *$J(.).log.
- Kept the existing *$J(.) coverage for app.log.1 / app.log.2.

Verification:
- Full test suite: 1064 passed, 0 failed, 7 skipped.
- Resource project build: passed with 0 warnings, 0 errors.

- Fixed/MultiFile rollover patterns with an index before the extension: - RolloverFilenameBuilder: the parser was dropping literal text after the final placeholder, including .log. - *$J(.).log now correctly expands: app.log → app.1.log → app.2.log. - Updated MultiFile mask dialog legend: - Fixed incorrectly displayed <date> and <prefix> placeholders in English and German resources. - Added both usage examples: *$J(.) → app.log, app.log.1, app.log.2 *$J(.).log → app.log, app.1.log, app.2.log - Added the examples in English, German, and Chinese. - Enlarged the dialog and syntax-help label so the date-format lines are no longer clipped. - Fixed/Items in menu File/Multifile -> "Enable MultiFile" and "Multi file mask...", were always greyed out. Now they are displayed normally after the .log file is open. - removed the BackColor and ForeColor assignments for both: - multiFileEnabledStripMenuItem - multifileMaskToolStripMenuItem - Added regression coverage: - Filename-builder tests for app.1.log and app.2.log. - Reader-level test that loads app.log, app.1.log, and app.2.log in correct order using *$J(.).log. - Kept the existing *$J(.) coverage for app.log.1 / app.log.2. Verification: - Full test suite: 1064 passed, 0 failed, 7 skipped. - Resource project build: passed with 0 warnings, 0 errors.

Hirogen · 2026-08-28T08:16:01Z

            }
        }

+        _ = result.Append(Regex.Escape(segment.ToString()));


Duplicated Code — [RolloverFilenameBuilder.cs:241] is the exact shape of the state-0 flush at line 202. A tiny local FlushEscaped() would let both share it

Added FlushEscaped() to share duplicated escaping code.

Hirogen · 2026-08-28T08:22:44Z

            }
        }

+        _ = result.Append(Regex.Escape(segment.ToString()));


Index parsing from a rotated file is still broken. Spec: "app.1.log → Rotated log (Index 1)". RolloverFilenameHandler calls SetFileName on whatever file the user opens; for $J(.).log the regex .(?'index'\d*).log has a greedy .* that swallows the digit in app.1.log, so Index parses as 0 and BuildFileName would produce app.1.1.log. Grouping only works when the active file (app.log) is opened. The same flaw pre-exists for *$J(.) with app.log.1, so it's parity rather than a regression — so the index mapping is only partially delivered.

fixed parsing of $J(<prefix>) from rotated files, so both app.log.1 and app.1.log correctly identify index 1.

made wildcard matching non-greedy and anchored the generated regex to the complete filename.

updated rebuilding logic to remove an existing prefix plus index together before inserting the new index.

fixed $D(...) parsing to use positions in the escaped format string, preventing errors when a literal regex character such as . appears before $D

Added coverage for opening:

engine.log.1 with *$J(.) → builds engine.log.2

engine.1.log with *$J(.).log → builds engine.2.log

Hirogen · 2026-08-28T08:23:37Z

    [TestCase("engine1.log", "engine2.log","engine$J.log")]
    [TestCase("engine.log", "engine.log.1","*$J(.)")]
+    [TestCase("engine.log", "engine.1.log", "*$J(.).log")]
    [TestCase("engine_2010-06-12.log", "engine_2010-06-12.log.1", "*$D(yyyy-MM-dd).log$J(.)")]


$I untested. For "$J, $I" support, the fix itself generalizes, but no test covers $I or $D followed by a trailing literal (e.g. *$D(yyyy-MM-dd)$J(.).log).

Added cases which cover:

$I with a trailing literal .log, starting from a rotated file.

$D plus $J(.) followed by a trailing .log, also starting from a rotated file.

Hirogen · 2026-08-28T08:24:49Z

    [TestCase("engine1.log", "engine2.log","engine$J.log")]
    [TestCase("engine.log", "engine.log.1","*$J(.)")]
+    [TestCase("engine.log", "engine.1.log", "*$J(.).log")]
    [TestCase("engine_2010-06-12.log", "engine_2010-06-12.log.1", "*$D(yyyy-MM-dd).log$J(.)")]


ParseFormatString computes datePos from the original string but edits the escaped one — a literal with regex metachars before $D (e.g. app.$D(yyyy-MM-dd)) corrupts the regex. Not introduced here, but the new trailing-literal support makes such patterns likelier.

Fixed by locating and parsing $D(...) in the escaped format string. Offsets remain correct when literal regex metacharacters appear before the date placeholder.
Added a regression test for app.$D(yyyy-MM-dd).log that verifies date parsing and rebuilding.

Fixed by locating and parsing $D(...) in the escaped format string. Offsets remain correct when literal regex metacharacters appear before the date placeholder. Added a regression test for app.$D(yyyy-MM-dd).log that verifies date parsing and rebuilding. Added cases which cover: - $I with a trailing literal .log, starting from a rotated file. - $D plus $J(.) followed by a trailing .log, also starting from a rotated file.

- Added FlushEscaped() to share duplicated escaping code. - Fixed parsing of $J(<prefix>) from rotated files, so both: - app.log.1 - app.1.log correctly identify index 1. - Made wildcard matching non-greedy and anchored the generated regex to the complete filename. - Updated rebuilding logic to remove an existing prefix plus index together before inserting the new index. - Fixed $D(...) parsing to use positions in the escaped format string, preventing errors when a literal regex character such as . appears before $D.

Pr0metheus2 · 2026-08-29T10:20:41Z

Check please

…mid-filename-index-tags-(app.1.log)

Hirogen · 2026-08-31T14:39:13Z

+        {
+            _ = result.Append(Regex.Escape(segment.ToString()));
+            segment = new StringBuilder();
+        }


extract it to a real function not a function in a function, this only leads to unreadable code

Hirogen · 2026-08-31T14:40:48Z

        StringBuilder result = new();
        StringBuilder segment = new();

+        void FlushEscaped ()


FlushEscaped() covers only case 0, while case 1 and case 3 still inline _ = result.Append(segment); segment = new StringBuilder();.

Hirogen · 2026-08-31T14:42:10Z

        if (_indexGroup != null && _indexGroup.Success)
        {
-            fileName = fileName.Remove(_indexGroup.Index, _indexGroup.Length);
+            var indexPosition = _indexGroup.Index;


Hidden invariant / Feature Envy — indexPosition = _condGroup.Index; indexLength += _condGroup.Length; silently assumes cond is contiguous and immediately precedes index — an invariant set 60 lines away in ParseFormatString. Uncommented; changing either regex breaks the other.

Hirogen · 2026-08-31T14:44:28Z

    }

+    [Test]
+    public void BuildFileName_DatePatternAfterRegexMetacharacter_IncrementsDate ()


BuildFileName_X_Y while the file's existing methods are TestFilenameAnd1/2.

Hirogen · 2026-08-31T14:44:42Z

        _hideZeroIndex = fmt.Contains("$J", StringComparison.Ordinal);
        fmt = fmt.Replace("$I", "(?'index'[\\d]+)", StringComparison.Ordinal);
-        fmt = fmt.Replace("$J", "(?'index'[\\d]*)", StringComparison.Ordinal);
+        var optionalIndexPattern = _condContent != null


optionalIndexPattern reads as "the pattern is optional";

Hirogen · 2026-08-31T14:45:32Z


        File.Copy(Path.Combine(_testDataDirectory, "app.log"), _logFile);
        File.Copy(Path.Combine(_testDataDirectory, "app.log.1"), _logFile + ".1");
+        File.Copy(Path.Combine(_testDataDirectory, "app.1.log"), Path.Combine(_testDirectory, "app.1.log"));


SetUp copies app.1.log/app.2.log unconditionally, so all four tests now see two extra files though only the new one needs them.

Hirogen · 2026-08-31T14:47:10Z

-        fmt = fmt.Replace("*", ".*", StringComparison.Ordinal);
+        fmt = fmt.Replace("*", ".*?", StringComparison.Ordinal);
        _hideZeroIndex = fmt.Contains("$J", StringComparison.Ordinal);
        fmt = fmt.Replace("$I", "(?'index'[\\d]+)", StringComparison.Ordinal);


"Allow index tags ($J, $I) to appear before a fixed file extension suffix." RolloverFilenameBuilder.cs:189 still maps $I → (?'index'[\d]+); only $J gets the prefix-aware alternation (:190-193). So *$I.log cannot match the active file app.log — SetFileName fails, IsIndexPattern stays false, no chain is built. The one new $I test (RollingNameTest.cs:36, engine1.log→engine2.log) starts from a numbered file and never exercises the failing case.

Hirogen · 2026-08-31T14:48:01Z

-$D(&amp;lt;date&amp;gt;) = Datumsmuster
+$D(&lt;date&gt;) = Datumsmuster
 $I = Dateiindexnummer
 $J = Dateiindexnummer, versteckt wenn 09


still reads $J = Dateiindexnummer, versteckt wenn 09 — should be 0. Correct in the English and Chinese files.

Hirogen · 2026-08-31T14:49:43Z

        }

-        fmt = fmt.Replace("*", ".*", StringComparison.Ordinal);
+        fmt = fmt.Replace("*", ".*?", StringComparison.Ordinal);


.→.? and :194 \A…\z anchoring change every mask, not just ones with trailing literals. It holds because RolloverFilenameHandler.cs:39 passes a bare filename, not a path — but that invariant is undocumented and untested; a full path with any non-*-prefixed mask now fails where it previously matched.

Hirogen · 2026-08-31T14:50:36Z

@@ -116,15 +116,23 @@ public string BuildFileName ()



A saved mask *$J(.).log previously behaved as *$J(.) and matched app.log.1; it now means app.1.log. That's what the spec wants, but existing user settings change

Pr0metheus2 added 2 commits August 26, 2026 12:07

test: add multi-file index test data

3989ae2

Hirogen requested changes Aug 28, 2026

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Pr0metheus2 added 4 commits August 29, 2026 11:36

Fixed from when to wenn

15c3d96

Removed old commented lines

905c979

Merge branch 'LogExperts:Development' into fix/MultiFile-support-for-…

2a5e1ed

…mid-filename-index-tags-(app.1.log)

Hirogen requested changes Aug 31, 2026

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Pr0metheus2 commented Aug 26, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Pr0metheus2 commented Aug 29, 2026

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Pr0metheus2 commented Aug 26, 2026 •

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