vcpkg remove does not update the status database after package removal

[rkitover]

---

Is your feature request related to a problem? Please describe.
The Status: field of a package does not get updated from install ok installed immediately after its removal, a subsequent operation such as list is required for the database to be updated.

Proposed solution
It should get updated immediately on a remove.

Additional context
Here is the log from my terminal illustrating the issue:

✔ ~\src\vcpkg\installed\vcpkg [master ≡]
rkitover@epycwin > grep sfml -A 10 .\status
Package: sfml
Version: 2.5.1
Port-Version: 9
Depends: freetype, libflac, libogg, libvorbis, openal-soft, stb
Architecture: x64-windows-static
Multi-Arch: same
Abi: 8dc17b8325a06029c61f264bbfe0f10464b57f6b
Description: Simple and fast multimedia library
Type: Port
Status: install ok installed

✔ ~\src\vcpkg\installed\vcpkg [master ≡]
rkitover@epycwin > vcpkg remove sfml:x64-windows-static
Your feedback is important to improve Vcpkg! Please take 3 minutes to complete our survey by running: vcpkg contact --survey
The following packages will be removed:
    sfml:x64-windows-static
Removing package sfml:x64-windows-static...
Removing package sfml:x64-windows-static... done
✔ ~\src\vcpkg\installed\vcpkg [master ≡]
rkitover@epycwin > grep sfml -A 10 .\status
Package: sfml
Version: 2.5.1
Port-Version: 9
Depends: freetype, libflac, libogg, libvorbis, openal-soft, stb
Architecture: x64-windows-static
Multi-Arch: same
Abi: 8dc17b8325a06029c61f264bbfe0f10464b57f6b
Description: Simple and fast multimedia library
Type: Port
Status: install ok installed

✔ ~\src\vcpkg\installed\vcpkg [master ≡]
rkitover@epycwin > vcpkg list *> $null
✔ ~\src\vcpkg\installed\vcpkg [master ≡]
rkitover@epycwin > grep sfml -A 10 .\status
Package: sfml
Version: 2.5.1
Port-Version: 9
Depends: freetype, libflac, libogg, libvorbis, openal-soft, stb
Architecture: x64-windows-static
Multi-Arch: same
Abi: 8dc17b8325a06029c61f264bbfe0f10464b57f6b
Description: Simple and fast multimedia library
Type: Port
Status: purge ok not-installed

[MVoz]

this is normal, the status is not immediately updated
repeat the installation command and everything will be ok

[rkitover]

I understand that it does not cause problems in terms of functionality, however I would disagree that the database being in an inconsistent state is normal, but that is for you to decide.

[MVoz]

it's always been that way for as long as I can remember

[linquize]

This design also causes #10812

[JackBoosY]

@BillyONeal I think it's a vcpkg bug, or it's by design?

[BillyONeal]

Seems like a bug to me.

[ras0219]

This is not a bug: the status database is more nuanced than a single file.

Specifically, during execution, vcpkg writes update files that contain "deltas" to the status db. At any given point in time, the database should be considered as the sum of the status file and all update files.

On launch, when loading the status db, vcpkg first performs a compacting step that computes the entire consolidated status file and writes that back out (atomically) to the status database. This is why you observe that running vcpkg list appears to "fix" the status file -- it performs a "gc" from many files down to one.

The reason to not write the database out on every update is that it would make installing N packages an O(N^2) operation -- every install step would need to re-write the binary paragraph of every install step before it. The reason to consolidate is to avoid needing to access O(N) files on every execution.

tldr; not a bug, by design.

[rkitover]

Right so, what is the problem with updating the database after every COMMAND, if a command installs multiple packages it can still do that.

[BillyONeal]

The reason to not write the database out on every update is that it would make installing N packages an O(N^2) operation -- every install step would need to re-write the binary paragraph of every install step before it. The reason to consolidate is to avoid needing to access O(N) files on every execution.

The compressed version of the database could be written as part of vcpkg remove without turning all operations into O(n^2).

[JackBoosY]

Duplicated to #10812.