Set distro family from ID line if no ID_LIKE line is found

See #456.

test/test_unit_query_distro_family.py

@@ -3,14 +3,16 @@
 import pytest
 
 
-@pytest.mark.parametrize("condition", ["os-release", "os-release-quotes", "missing"])
+@pytest.mark.parametrize("condition", ["os-release", "os-release-quotes", "missing", "fallback"])
 def test_query_distro_family(runner, yadm, tmp_path, condition):
     """Match ID_LIKE when present"""
     test_family = "testfamily"
     os_release = tmp_path.joinpath("os-release")
     if "os-release" in condition:
         quotes = '"' if "quotes" in condition else ""
-        os_release.write_text(f"testing\nID_LIKE={quotes}{test_family}{quotes}\nfamily")
+        os_release.write_text(f"testing\nID=test\nID_LIKE={quotes}{test_family}{quotes}\nfamily")
+    elif condition == "fallback":
+        os_release.write_text(f'testing\nID="{test_family}"\nfamily')
     script = f"""
         YADM_TEST=1 source {yadm}
         OS_RELEASE="{os_release}"
@@ -19,7 +21,7 @@ def test_query_distro_family(runner, yadm, tmp_path, condition):
     run = runner(command=["bash"], inp=script)
     assert run.success
     assert run.err == ""
-    if "os-release" in condition:
-        assert run.out.rstrip() == test_family
-    else:
+    if condition == "missing":
         assert run.out.rstrip() == ""
+    else:
+        assert run.out.rstrip() == test_family

yadm

@@ -1499,7 +1499,7 @@ function exclude_encrypted() {
 }
 
 function query_distro() {
-  distro=""
+  local distro=""
   if command -v "$LSB_RELEASE_PROGRAM" &> /dev/null; then
     distro=$($LSB_RELEASE_PROGRAM -si 2>/dev/null)
   elif [ -f "$OS_RELEASE" ]; then
@@ -1515,17 +1515,19 @@ function query_distro() {
 }
 
 function query_distro_family() {
-  family=""
+  local family=""
   if [ -f "$OS_RELEASE" ]; then
     while IFS='' read -r line || [ -n "$line" ]; do
       if [[ "$line" = ID_LIKE=* ]]; then
         family="${line#ID_LIKE=}"
-        family="${family//\"}"
         break
+      elif [[ "$line" = ID=* ]]; then
+        family="${line#ID=}"
+        # No break, only used as fallback in case ID_LIKE isn't found
       fi
     done < "$OS_RELEASE"
   fi
-  echo "$family"
+  echo "${family//\"}"
 }
 
 function process_global_args() {

yadm.1

@@ -511,7 +511,8 @@ or by inspecting the ID from
 .BR distro_family , " f
 Valid if the value matches the distro family (ignoring case).
 Distro family is calculated by inspecting the ID_LIKE line from
-.BR "/etc/os-release" .
+.B "/etc/os-release"
+(or ID if no ID_LIKE line is found).
 .TP
 .BR os , " o
 Valid if the value matches the OS.