Fix memory leak in LiftWriter

[Copilot]

LiftWriter in SIL.DictionaryServices appears to leak several MB per use; investigation and fix are needed.

• Implemented disposal of temporary XmlReader/StringReader instances created during language form validation to eliminate per-call resource leaks.
• Awaiting approval to address the remaining potential XmlWriter lifetime/Disposed-state issue.

No additional code paths changed beyond the temporary reader disposal; further remediation pending approval.

Original prompt

We are using LiftWriter from the SIL.DictionaryServices package and it seems to leak a few megabytes of memory every time it is used.

Make a plan for analyzing the code for leaks and wait before approval before beginning.

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This change is 

[jasonleenaylor]

@copilot Do the inspection step and report on the results. Wait for interaction before continuing.

[Copilot]

@copilot Do the inspection step and report on the results. Wait for interaction before continuing.

Inspection complete. Findings: LiftWriter owns only an XmlWriter; End closes it but does not set Disposed or clear the reference, so repeated End without Dispose leaves the object holding its writer until GC (no finalizer in release), which could explain transient memory growth if callers skip Dispose. Dispose(bool) closes the writer, but VerifyNotDisposed is inverted (throws when not disposed), so it isn’t usable to guard against improper reuse. Also noticed small resource hygiene gaps: per-Add language form validation creates XmlReader/StringReader instances without disposing them. No code changes made yet—let me know if you want me to proceed with a concrete repro harness and fixes (e.g., dispose/clear writer, correct Disposed semantics, dispose temp readers).

[jasonleenaylor]

@copilot Show the XmlReader/StringReader instance leak and a proposed solution, wait for approval before making a commit.

[jasonleenaylor]

@copilot Make the proposed change and commit it. Then show in context the possible XmlWriter leak and a proposed fix. Wait for approval before committing.

[Copilot]

@copilot Make the proposed change and commit it. Then show in context the possible XmlWriter leak and a proposed fix. Wait for approval before committing.

XmlReader/StringReader disposal fixed in 87036ce (WriteLanguageFormsInWrapper now wraps the XmlReader creation in nested using blocks). Possible XmlWriter leak: End() flushes/closes the writer but never marks Disposed or releases the reference, so callers that only call End() keep a live LiftWriter holding a closed XmlWriter until GC. Proposed fix (pending approval): have End() call Dispose(true) (or at least _writer?.Dispose(); Disposed = true;) and adjust VerifyNotDisposed to check if (Disposed) throw new ObjectDisposedException(...), so the writer is properly disposed and future misuse is prevented without waiting for GC. No further commits made yet; ready to implement once approved.

[github-actions]

Palaso Tests

     3 files   -     1       3 suites   - 1   8m 19s ⏱️ - 2m 30s
 5 092 tests ±    0   4 859 ✅ ±    0  233 💤 ± 0  0 ❌ ±0 
14 761 runs   - 1 830  14 128 ✅  - 1 743  633 💤  - 87  0 ❌ ±0 

Results for commit 80c93da. ± Comparison against base commit d010103.

♻️ This comment has been updated with latest results.

[jasonleenaylor]

The other suggestion was not likely to be the cause so I've ignored it for now.

[imnasnainaec]

@copilot Add a very brief summary of this fix to the "Fixed" subsection of the "Unreleased" section of CHANGELOG.md.

[imnasnainaec]

@imnasnainaec reviewed 2 of 2 files at r1, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @jasonleenaylor)