gramps
5b9ff5b742
Rewrite HANDOFF.md: Phase 2 is pushed at 1f4624c (stale claim corrected);
Phase 3 commit rows A-E + Controls/index.md listed as local-only, push pending
on explicit approval. Records the re-structuring principle (split by concern,
500-line count is a ceiling not the goal) and the session's truncation-accident
lesson. MyMistakes.md gains the never-awk-into-the-source-you-read rule.
70 lines
3.5 KiB
Markdown
70 lines
3.5 KiB
Markdown
# MyMistakes.md
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> **Two jobs**, distinguished by heading:
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>
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> 1. **Per-task failure log** — updated before every commit touching that task:
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> current iteration + why the last one failed. On task complete, committed AND
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> pushed → truncate to this stub. A new task does NOT seed this file until its
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> first failure.
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> 2. **Recipes registry** (DERIVED-SOLUTION RULE, see `AGENTS.md` 🔬) — the durable
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> home for one-off derived solutions, recipes, and how-tos. The moment you work
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> out a reusable solution, write it here **in the same session**. GREP THIS FILE
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> FIRST when you hit a "I've done this before but have to figure it out again"
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> wall. Recipe entries stay permanently (they are NOT truncated on task
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> completion) — only the failure log truncates.
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## 🔬 Recipes registry
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### Shrink / re-encode an image for the README (screenshots → small hero image)
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Worked out 2026-08-29 (the recipe was NEVER recorded the first time it was done, so
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it had to be re-derived from scratch — that's the incident this entry exists to end).
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**Approach:** a throwaway Windows-dotnet console app uses WPF's imaging stack
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(`System.Windows.Media.Imaging`) — same framework the app runs on, zero NuGet
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packages, high-quality downscale via `TransformedBitmap`. Screenshots compress
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**far smaller as JPEG than PNG** (PNG 1400px = ~1.2MB; JPEG q82 1400px = ~188KB).
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**Recipe (run via the Windows dotnet host from WSL):**
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1. Create `imgresize.csproj` targeting `net8.0-windows` with `<UseWPF>true</UseWPF>`
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(SDK controller). Put it in a Windows-visible temp path, e.g.
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`C:\Users\gramp\AppData\Local\Temp\imgresize` — NOT `/tmp` (Windows dotnet can't
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reach a Linux-only path reliably).
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2. `Program.cs`: load `BitmapImage` (`CacheOption=OnLoad` → `Freeze()`), downscale
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with `TransformedBitmap(src, new ScaleTransform(scale, scale))` to max width
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(1400 for the README hero), encode with `JpegBitmapEncoder { QualityLevel = 82 }`,
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save.
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3. Run:
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```bash
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"/mnt/c/Program Files/dotnet/dotnet.exe" run -c Release --project .
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-- "C:\Users\gramp\Downloads\Screenshot 2026-08-29 075626.png"
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"C:\Users\gramp\Documents\Code\projects\ytLive\docs\ytLlive-preview.jpg" 1400
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```
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4. Point `README.md` at the `.jpg` (not `.png`).
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**Result:** 3.2MB screenshot → 1400×794 → **188KB** `ytLlive-preview.jpg` in `docs/`.
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---
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## Splitting a large file into partials — NEVER `awk … > SRC` while awking SRC
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(2026-08-31, Commit D) Tried to split `SocialsDialogViewModel.cs` in one line:
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`{ awk '…' SRC; echo ""; awk '…2…' SRC; } > SRC`. The **first write truncated
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SRC to 1 line**, so the second `awk` read the already-truncated file → the whole
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source was lost (1 line left). Recovered with `git checkout -- SRC`, then redid
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it, but the same bug could have meant making it up from scratch.
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**Rule:** when a cut needs N blocks from one source into N files, never write a
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block back onto the source that the `awk`s still read. Instead:
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1. Read the source **once** at the start into temp files (`mktemp -d`, one file
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per block), with a `$D` variable you carry forward.
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2. Verify block sizes (`wc -l`) and brace balance (`python3 -c` counting `{`/`}`)
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before touching any real file.
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3. Then assemble each new file from `cat D/block …` — never truncating the source
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until every read is done.
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`git status` can't save you here if you don't notice until the file is gone —
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`git checkout -- <path>` from the last commit is the recovery. Cheap insurance:
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restore-then-retry, do it atomically from temp files the first time.
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