Fix pj_obj_create() grid alternative resolution when old_proj_grid_name is NULL#4701
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rouault merged 1 commit intoOSGeo:masterfrom Mar 7, 2026
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…olution When pj_obj_create() exports a coordinate operation to a PROJ string, it previously passed nullptr as the database context to PROJStringFormatter. This prevented substitutePROJAlternativeGridNames() from resolving grid names via the grid_alternatives table. For grid transformations where old_proj_grid_name is NULL (153 entries in the standard PROJ database), the file-level fallback (getProjGridName) cannot resolve the grid because it queries old_proj_grid_name. Only lookForGridAlternative (which queries original_grid_name) can resolve these grids, but it requires a database context. This change adds getDatabaseContextIfOpen() to projCppContext, which returns the cached database context if already opened (e.g. from a prior proj_create_from_database call), without attempting to open proj.db. This preserves the original intent of commit 63c491e that callers using plain pipeline strings can run without proj.db. Adds a test for EPSG:9484 (grid href2008a.bin -> no_kv_href2008a.tif) which has a NULL old_proj_grid_name.
rouault
approved these changes
Mar 7, 2026
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The commit changed pj_obj_create() to pass nullptr as the database context to PROJStringFormatter::create(), which prevents substitutePROJAlternativeGridNames() from resolving grid names via the grid_alternatives table. The reson for the change was to add support for that plain pipeline strings should work without a proj.db.
Example: proj_create_from_database("EPSG","9484") returns a pipeline with the original grid name
href2008a.bininstead of the CDN nameno_kv_href2008a.tif, causing downstream failures.Fix: Use the database context if it is already open (e.g. when called from proj_create_from_database), but do not open it otherwise — preserving the original intent of 63c491e that plain pipeline strings work without proj.db.