# Extension patches
Patches in this directory are used to smoothen the process of introducing changes to DuckDB that break compatibility with an
out-of-tree extension. Extensions installed from git urls can automatically apply patches found in this directory. The APPLY_PATCHES flag 
should be used to explicitly enable this feature. For example,
lets say our extension config looks like this:

```shell
duckdb_extension_load(spatial
    DONT_LINK
    GIT_URL https://github.com/duckdb/duckdb_spatial
    GIT_TAG f577b9441793f9170403e489f5d3587e023a945f
    APPLY_PATCHES
)
```
In this example, upon downloading the spatial extension, all patches in the `.github/patches/extensions/spatial/*.patch`
will be automatically applied.

Note that the reason for having the APPLY_PATCHES flag explicitly enabled is to make it easier for developers reading
the extension config to detect a patch is present. For this reason, the patching mechanism will actually fail if `APPLY_PATCHES`
is set with no patches in `.github/patches/extensions/<ext>/*.patch`.

# Workflow
Imagine a change to DuckDB is introduced that breaks compatibility with extension X. The
workflow for this is as follows:

### PR #1: breaking change to DuckDB
- Commit breaking change to DuckDB
- Fix breakage in extension X, producing a patch with fix (be wary of already existing patches)
- Commit patch in `.github/patches/extensions/x/*.patch` using a descriptive name
- enable APPLY_PATCHES for extension X in `.github/config/out_of_tree_extensions.cmake` (if not already enabled)

### PR #2: patch to extension X
- Apply (all) the patch(es) in `.github/patches/extensions/x/*.patch` to extension X.

### PR #3: update extension X in DuckDB
- Remove patches in `.github/patches/extensions/x/*.patch`
- Remove `APPLY_PATCHES` flag from config
- Update hash of extension in config