Use data search path as default for databases.

This way databases can be found in several locations,
reducing the need for sage_conf.

Author: tornaria

src/sage/env.py

@@ -203,13 +203,14 @@ def var(key: str, *fallbacks: Optional[str], force: bool = False) -> Optional[st
                          SAGE_SHARE,
                          ])))
 
-# installation directories for various packages
-GRAPHS_DATA_DIR = var("GRAPHS_DATA_DIR", join(SAGE_SHARE, "graphs"))
-ELLCURVE_DATA_DIR = var("ELLCURVE_DATA_DIR", join(SAGE_SHARE, "ellcurves"))
-POLYTOPE_DATA_DIR = var("POLYTOPE_DATA_DIR", join(SAGE_SHARE, "reflexive_polytopes"))
+# database directories, the default is to search in SAGE_DATA_PATH
+CREMONA_LARGE_DATA_DIR = var("CREMONA_LARGE_DATA_DIR")
+CREMONA_MINI_DATA_DIR = var("CREMONA_MINI_DATA_DIR")
+ELLCURVE_DATA_DIR = var("ELLCURVE_DATA_DIR")
+GRAPHS_DATA_DIR = var("GRAPHS_DATA_DIR")
+POLYTOPE_DATA_DIR = var("POLYTOPE_DATA_DIR")
 
-CREMONA_MINI_DATA_DIR = var("CREMONA_MINI_DATA_DIR", join(SAGE_SHARE, "cremona"))
-CREMONA_LARGE_DATA_DIR = var("CREMONA_LARGE_DATA_DIR", join(SAGE_SHARE, "cremona"))
+# installation directories for various packages
 JMOL_DIR = var("JMOL_DIR", join(SAGE_SHARE, "jmol"))
 MATHJAX_DIR = var("MATHJAX_DIR", join(SAGE_SHARE, "mathjax"))
 MTXLIB = var("MTXLIB", join(SAGE_SHARE, "meataxe"))

src/sage/features/databases.py

@@ -68,6 +68,7 @@ def __init__(self, name="cremona"):
         from sage.env import CREMONA_MINI_DATA_DIR, CREMONA_LARGE_DATA_DIR
         CREMONA_DATA_DIRS = set([CREMONA_MINI_DATA_DIR, CREMONA_LARGE_DATA_DIR])
         CREMONA_DATA_DIRS.discard(None)
+        search_path = CREMONA_DATA_DIRS or sage_data_path("cremona")
 
         spkg = "database_cremona_ellcurve"
         spkg_type = "optional"
@@ -77,7 +78,7 @@ def __init__(self, name="cremona"):
 
         StaticFile.__init__(self, f"database_{name}_ellcurve",
                             filename=f"{name}.db",
-                            search_path=CREMONA_DATA_DIRS,
+                            search_path=search_path,
                             spkg=spkg,
                             type=spkg_type,
                             url="https://github.com/JohnCremona/ecdata",
@@ -104,9 +105,11 @@ def __init__(self):
             True
         """
         from sage.env import ELLCURVE_DATA_DIR
+        search_path = ELLCURVE_DATA_DIR or sage_data_path("ellcurves")
+
         StaticFile.__init__(self, "database_ellcurves",
                             filename='rank0',
-                            search_path=ELLCURVE_DATA_DIR,
+                            search_path=search_path,
                             spkg="elliptic_curves",
                             type="standard",
                             description="William Stein's database of interesting curve")
@@ -132,9 +135,11 @@ def __init__(self):
             True
         """
         from sage.env import GRAPHS_DATA_DIR
+        search_path = GRAPHS_DATA_DIR or sage_data_path("graphs")
+
         StaticFile.__init__(self, "database_graphs",
                             filename='graphs.db',
-                            search_path=GRAPHS_DATA_DIR,
+                            search_path=search_path,
                             spkg="graphs",
                             type="standard",
                             description="A database of graphs")
@@ -160,7 +165,8 @@ def __init__(self):
             True
         """
         StaticFile.__init__(self, "database_jones_numfield",
-                            filename='jones/jones.sobj',
+                            filename='jones.sobj',
+                            search_path=sage_data_path("jones"),
                             spkg="database_jones_numfield",
                             description="John Jones's tables of number fields")
 
@@ -244,14 +250,15 @@ def __init__(self, name='polytopes_db'):
             'Hodge4d'
         """
         from sage.env import POLYTOPE_DATA_DIR
+        search_path = POLYTOPE_DATA_DIR or sage_data_path("reflexive_polytopes")
 
         dirname = "Full3d"
         if name == "polytopes_db_4d":
             dirname = "Hodge4d"
 
         StaticFile.__init__(self, name,
                             filename=dirname,
-                            search_path=POLYTOPE_DATA_DIR)
+                            search_path=search_path)
 
 
 def all_features():