Support git apply -p1 by default

See #4116.

Author: Zac-HD

hypothesis-python/RELEASE.rst

@@ -0,0 +1,4 @@
+RELEASE_TYPE: patch
+
+This patch tweaks the paths in ``@example(...)`` patches, so that
+both ``git apply`` and ``patch`` will work by default.

hypothesis-python/src/hypothesis/extra/_patching.py

@@ -205,8 +205,8 @@ def make_patch(triples, *, msg="Hypothesis: add explicit examples", when=None):
         ud = difflib.unified_diff(
             source_before.splitlines(keepends=True),
             source_after.splitlines(keepends=True),
-            fromfile=str(fname),
-            tofile=str(fname),
+            fromfile=f"./{fname}",  # git strips the first part of the path by default
+            tofile=f"./{fname}",
         )
         diffs.append("".join(ud))
     return "".join(diffs)

hypothesis-python/tests/patching/test_patching.py

@@ -74,8 +74,8 @@ def test_adds_simple_patch(tst, example, expected):
 
 
 SIMPLE_PATCH_BODY = f'''\
---- {WHERE}
-+++ {WHERE}
+--- ./{WHERE}
++++ ./{WHERE}
 @@ -18,6 +18,7 @@
 
 
@@ -86,8 +86,8 @@ def fn(x):
 
 '''
 CASES_PATCH_BODY = f'''\
---- {WHERE}
-+++ {WHERE}
+--- ./{WHERE}
++++ ./{WHERE}
 @@ -25,6 +25,9 @@
  class Cases:
      @example(n=0, label="whatever")
@@ -98,8 +98,8 @@ def mth(self, n, label):
 
 '''
 TOPLEVEL_PATCH_BODY = f'''\
---- {WHERE_TOP}
-+++ {WHERE_TOP}
+--- ./{WHERE_TOP}
++++ ./{WHERE_TOP}
 @@ -19,5 +19,6 @@
 
 
@@ -109,8 +109,8 @@ def fn_top(x):
      """A trivial test function."""
 '''
 COVERING_PATCH_BODY = f'''\
---- {WHERE}
-+++ {WHERE}
+--- ./{WHERE}
++++ ./{WHERE}
 @@ -31,7 +31,7 @@
 
  @given(st.integers())