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demos/demo-20260515-111539-source-viewer-fix.md

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+# Demo: Source Viewer Fix
+
+*2026-05-15T10:15:39Z by Showboat dev*
+<!-- showboat-id: 50614918-1e97-44de-9247-3f39ca35af4a -->
+
+## Bug Fix: Source Viewer Showing Wrong File
+
+**Issue**: The source viewer in the Microprints page always showed 'defmodule Blogex' regardless of which file's Expand button was clicked.
+
+**Root Cause**: In `resolve_absolute_paths/1`, app files (e.g., `lib/firehose.ex`) were resolved using `Path.expand(path)` which expands relative to the current working directory instead of relative to the `app_root`. This caused app files to resolve to wrong paths.
+
+**Fix**: Changed `resolve_absolute_paths/1` to use `Path.join(app_root, path)` for all paths, ensuring both app files and `../blogex/...` files resolve correctly relative to the app directory.
+
+## Test Suite
+
+```bash
+cd app && mix test test/firehose_web/live/microprints_live_test.exs --color
+```
+
+```output
+Running ExUnit with seed: 924777, max_cases: 32
+
+........
+Finished in 0.9 seconds (0.9s async, 0.00s sync)
+8 tests, 0 failures
+```
+
+All 8 tests pass, confirming that `scan_source_files/0` returns correct paths for both app and blogex files.
+
+## UI Verification
+
+```bash {image}
+![Microprints page showing all source files](demos/screenshots/microprints-page.png)
+```
+
+![Microprints page showing all source files](f5e7eb02-2026-05-15.png)
+
+```bash {image}
+![Source viewer correctly shows defmodule Firehose for lib/firehose.ex](demos/screenshots/source-viewer-firehose.png)
+```
+
+![Source viewer correctly shows defmodule Firehose for lib/firehose.ex](28c17b37-2026-05-15.png)
+
+```bash {image}
+![Source viewer correctly shows defmodule FirehoseWeb.Router for lib/firehose_web/router.ex](demos/screenshots/source-viewer-router.png)
+```
+
+![Source viewer correctly shows defmodule FirehoseWeb.Router for lib/firehose_web/router.ex](1b3aa9ee-2026-05-15.png)
+
+## Acceptance Criteria Verification
+
+- [x] Source viewer displays actual source code of the specific file -- see UI Verification screenshots above
+- [x] App files (e.g., `lib/firehose.ex`) show correct content -- see source-viewer-firehose.png
+- [x] Router files (e.g., `lib/firehose_web/router.ex`) show correct content -- see source-viewer-router.png
+- [x] All 8 tests pass