fix(routing): let a reader come back from a legacy link - #183
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An adversarial pass over #172 and #182. **Following a legacy link trapped the reader.** From the news archive, opening `/PathwayBrowser/#1280218` and pressing Back stayed on the pathway -- six times over. The rewrite is the cause: the app writes state into the URL while the fragment is still there, so `/PathwayBrowser#1280218` and `?tab=details#1280218` both became history entries carrying it, and going back to such an entry rewrites it forward again. Both PRs shipped this; the `#R-HSA-…` links have had it since #172. Two changes. A fragment being consumed is no longer carried forward by the navigations that write state into the URL, so no entry retains it. And a dbId is navigated on immediately rather than after its lookup -- going first means the fragment is consumed in the same turn as a stable-id one, before anything else can record it -- with the URL then corrected to the stable id by a replace, which adds no entry. Measured from /about/news: a dbId link now takes 3 Backs to leave, a stable-id link 4, and a direct load 3. It was never. **I had also written a resolver that already existed.** `dbIdToStId` has been on this service all along, unused, and it is the better one: it asks `/data/query/<dbId>/stId` and gets 13 bytes, where mine fetched the whole object for one field -- 12,682. Mine is gone and the existing one has its first caller. Not fixed, and not mine: a pathway load adds two history entries of its own before any of this, which is why leaving still takes three Backs rather than one. Every navigation in this service pushes, including the ones that are only normalising the URL. Worth a look, but making them replace would also stop Back working between pathways, so it needs deciding rather than just changing. The escape is now a test, because it broke twice without anything noticing. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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Opening a pathway cost three presses of Back to get out of, and the first two did something nobody asked for. The app writes its own defaults into the URL, so `?tab=info` and then `?tab=details` each became a history entry: pressing Back stepped through tab changes the reader never made before it would leave the page. The URL still has to carry the tab -- a shared link has to open on the same thing -- so the fix is not to stop writing it. Being *given* a tab now replaces the entry; *choosing* one still adds to it. `details.component` already knew the difference, in `tabCameFromUrl`; there was just no way to tell the URL writer, so `settle()` is that way. From the news archive: one press of Back leaves, where it was three. Choosing the Molecule tab and pressing Back still returns to Details. Found while reviewing #183, where I called this pre-existing and left it. It was pre-existing, and it turned out to be one flag rather than the rework of navigation semantics I assumed -- the reason I gave for not doing it was wrong. Both halves are tested, because keeping the second is what stops the first turning into "Back does nothing in this app". Co-authored-by: Claude Opus 5 <noreply@anthropic.com>
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An adversarial pass over #172 and #182.
Following a legacy link trapped the reader
From
/about/news, opening/PathwayBrowser/#1280218and pressing Back stayed on the pathway — six times over. The reader could not get back to the news archive they came from.The rewrite is the cause. The app writes state into the URL while the fragment is still present, so
/PathwayBrowser#1280218and then?tab=details#1280218both became history entries carrying it — and going back to such an entry rewrites it forward again. Both PRs shipped this; the#R-HSA-…links have had it since #172.Two changes:
#1280218#R-HSA-202733R-HSA-1280218I had also written a resolver that already existed
dbIdToStIdhas been on this service all along, unused — and it is the better one: it asks/data/query/<dbId>/stIdand gets 13 bytes, where mine fetched the whole object to read one field off it — 12,682. Mine is gone, and the existing one has its first caller.Not fixed, and not mine
A pathway load adds two history entries of its own before any of this, which is why leaving still takes three Backs rather than one. Every navigation in this service pushes, including the ones that only normalise the URL. Worth a look — but making them replace would also stop Back working between pathways, so it needs deciding rather than just changing.
Tested
The escape is now a test, since it broke twice without anything noticing. Full preflight green; the release spec that opens all 21 v97 links passes on a dedicated run.
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