Support glob argument with --cache-show

changelog/5035.feature.rst

@@ -0,0 +1 @@
+The ``--cache-show`` option/action accepts an optional glob to show only matching cache entries.

doc/en/cache.rst

@@ -247,7 +247,7 @@ See the :ref:`cache-api` for more details.
 
 
 Inspecting Cache content
--------------------------------
+------------------------
 
 You can always peek at the content of the cache using the
 ``--cache-show`` command line option:
@@ -260,7 +260,7 @@ You can always peek at the content of the cache using the
     cachedir: $PYTHON_PREFIX/.pytest_cache
     rootdir: /home/sweet/project
     cachedir: $PYTHON_PREFIX/.pytest_cache
-    ------------------------------- cache values -------------------------------
+    --------------------------- cache values for '*' ---------------------------
     cache/lastfailed contains:
       {'test_50.py::test_num[17]': True,
        'test_50.py::test_num[25]': True,
@@ -277,8 +277,25 @@ You can always peek at the content of the cache using the
 
     ======================= no tests ran in 0.12 seconds =======================
 
+``--cache-show`` takes an optional argument to specify a glob pattern for
+filtering:
+
+.. code-block:: pytest
+
+    $ pytest --cache-show example/*
+    =========================== test session starts ============================
+    platform linux -- Python 3.x.y, pytest-4.x.y, py-1.x.y, pluggy-0.x.y
+    cachedir: $PYTHON_PREFIX/.pytest_cache
+    rootdir: $REGENDOC_TMPDIR, inifile:
+    cachedir: $PYTHON_PREFIX/.pytest_cache
+    ----------------------- cache values for 'example/*' -----------------------
+    example/value contains:
+      42
+
+    ======================= no tests ran in 0.12 seconds =======================
+
 Clearing Cache content
--------------------------------
+----------------------
 
 You can instruct pytest to clear all cache files and values
 by adding the ``--cache-clear`` option like this:

src/_pytest/cacheprovider.py

@@ -292,9 +292,13 @@ def pytest_addoption(parser):
     )
     group.addoption(
         "--cache-show",
-        action="store_true",
+        action="append",
+        nargs="?",
         dest="cacheshow",
-        help="show cache contents, don't perform collection or tests",
+        help=(
+            "show cache contents, don't perform collection or tests. "
+            "Optional argument: glob (default: '*')."
+        ),
     )
     group.addoption(
         "--cache-clear",
@@ -369,11 +373,16 @@ def cacheshow(config, session):
     if not config.cache._cachedir.is_dir():
         tw.line("cache is empty")
         return 0
+
+    glob = config.option.cacheshow[0]
+    if glob is None:
+        glob = "*"
+
     dummy = object()
     basedir = config.cache._cachedir
     vdir = basedir / "v"
-    tw.sep("-", "cache values")
-    for valpath in sorted(x for x in vdir.rglob("*") if x.is_file()):
+    tw.sep("-", "cache values for %r" % glob)
+    for valpath in sorted(x for x in vdir.rglob(glob) if x.is_file()):
         key = valpath.relative_to(vdir)
         val = config.cache.get(key, dummy)
         if val is dummy:
@@ -385,8 +394,8 @@ def cacheshow(config, session):
 
     ddir = basedir / "d"
     if ddir.is_dir():
-        contents = sorted(ddir.rglob("*"))
-        tw.sep("-", "cache directories")
+        contents = sorted(ddir.rglob(glob))
+        tw.sep("-", "cache directories for %r" % glob)
         for p in contents:
             # if p.check(dir=1):
             #    print("%s/" % p.relto(basedir))

testing/test_cacheprovider.py

@@ -196,6 +196,7 @@ def test_cache_show(testdir):
         """
         def pytest_configure(config):
             config.cache.set("my/name", [1,2,3])
+            config.cache.set("my/hello", "world")
             config.cache.set("other/some", {1:2})
             dp = config.cache.makedir("mydb")
             dp.ensure("hello")
@@ -204,20 +205,39 @@ def pytest_configure(config):
     )
     result = testdir.runpytest()
     assert result.ret == 5  # no tests executed
+
     result = testdir.runpytest("--cache-show")
-    result.stdout.fnmatch_lines_random(
+    result.stdout.fnmatch_lines(
         [
             "*cachedir:*",
-            "-*cache values*-",
-            "*my/name contains:",
+            "*- cache values for '[*]' -*",
+            "cache/nodeids contains:",
+            "my/name contains:",
             "  [1, 2, 3]",
-            "*other/some contains*",
-            "  {*1*: 2}",
-            "-*cache directories*-",
+            "other/some contains:",
+            "  {*'1': 2}",
+            "*- cache directories for '[*]' -*",
             "*mydb/hello*length 0*",
             "*mydb/world*length 0*",
         ]
     )
+    assert result.ret == 0
+
+    result = testdir.runpytest("--cache-show", "*/hello")
+    result.stdout.fnmatch_lines(
+        [
+            "*cachedir:*",
+            "*- cache values for '[*]/hello' -*",
+            "my/hello contains:",
+            "  *'world'",
+            "*- cache directories for '[*]/hello' -*",
+            "d/mydb/hello*length 0*",
+        ]
+    )
+    stdout = result.stdout.str()
+    assert "other/some" not in stdout
+    assert "d/mydb/world" not in stdout
+    assert result.ret == 0
 
 
 class TestLastFailed(object):