Documentation - More examples for git bisect

diff --git a/t/t5303-pack-corruption-resilience.sh b/t/t5303-pack-corruption-resilience.sh
index 31b20b21d23c2066fd124bf6a33dbdc689930170..d4e30fc43c68ed9b0fc175f2a88a07de6458f58e 100755 (executable)
--- a/t/t5303-pack-corruption-resilience.sh
+++ b/t/t5303-pack-corruption-resilience.sh
@@ -41,11 +41,17 @@ create_new_pack() {
     git verify-pack -v ${pack}.pack
 }
 
+do_repack() {
+    pack=`printf "$blob_1\n$blob_2\n$blob_3\n" |
+          git pack-objects $@ .git/objects/pack/pack` &&
+    pack=".git/objects/pack/pack-${pack}"
+}
+
 do_corrupt_object() {
     ofs=`git show-index < ${pack}.idx | grep $1 | cut -f1 -d" "` &&
     ofs=$(($ofs + $2)) &&
     chmod +w ${pack}.pack &&
-    dd if=/dev/zero of=${pack}.pack count=1 bs=1 conv=notrunc seek=$ofs &&
+    dd of=${pack}.pack count=1 bs=1 conv=notrunc seek=$ofs &&
     test_must_fail git verify-pack ${pack}.pack
 }
 
@@ -60,7 +66,7 @@ test_expect_success \
 
 test_expect_success \
     'create corruption in header of first object' \
-    'do_corrupt_object $blob_1 0 &&
+    'do_corrupt_object $blob_1 0 < /dev/zero &&
      test_must_fail git cat-file blob $blob_1 > /dev/null &&
      test_must_fail git cat-file blob $blob_2 > /dev/null &&
      test_must_fail git cat-file blob $blob_3 > /dev/null'
@@ -119,7 +125,7 @@ test_expect_success \
     'create corruption in header of first delta' \
     'create_new_pack &&
      git prune-packed &&
-     do_corrupt_object $blob_2 0 &&
+     do_corrupt_object $blob_2 0 < /dev/zero &&
      git cat-file blob $blob_1 > /dev/null &&
      test_must_fail git cat-file blob $blob_2 > /dev/null &&
      test_must_fail git cat-file blob $blob_3 > /dev/null'
@@ -133,6 +139,15 @@ test_expect_success \
      git cat-file blob $blob_2 > /dev/null &&
      git cat-file blob $blob_3 > /dev/null'
 
+test_expect_success \
+    '... and then a repack "clears" the corruption' \
+    'do_repack &&
+     git prune-packed &&
+     git verify-pack ${pack}.pack &&
+     git cat-file blob $blob_1 > /dev/null &&
+     git cat-file blob $blob_2 > /dev/null &&
+     git cat-file blob $blob_3 > /dev/null'
+
 test_expect_success \
     'create corruption in data of first delta' \
     'create_new_pack &&
@@ -152,11 +167,20 @@ test_expect_success \
      git cat-file blob $blob_2 > /dev/null &&
      git cat-file blob $blob_3 > /dev/null'
 
+test_expect_success \
+    '... and then a repack "clears" the corruption' \
+    'do_repack &&
+     git prune-packed &&
+     git verify-pack ${pack}.pack &&
+     git cat-file blob $blob_1 > /dev/null &&
+     git cat-file blob $blob_2 > /dev/null &&
+     git cat-file blob $blob_3 > /dev/null'
+
 test_expect_success \
     'corruption in delta base reference of first delta (OBJ_REF_DELTA)' \
     'create_new_pack &&
      git prune-packed &&
-     do_corrupt_object $blob_2 2 &&
+     do_corrupt_object $blob_2 2 < /dev/zero &&
      git cat-file blob $blob_1 > /dev/null &&
      test_must_fail git cat-file blob $blob_2 > /dev/null &&
      test_must_fail git cat-file blob $blob_3 > /dev/null'
@@ -171,17 +195,75 @@ test_expect_success \
      git cat-file blob $blob_3 > /dev/null'
 
 test_expect_success \
-    'corruption in delta base reference of first delta (OBJ_OFS_DELTA)' \
+    '... and then a repack "clears" the corruption' \
+    'do_repack &&
+     git prune-packed &&
+     git verify-pack ${pack}.pack &&
+     git cat-file blob $blob_1 > /dev/null &&
+     git cat-file blob $blob_2 > /dev/null &&
+     git cat-file blob $blob_3 > /dev/null'
+
+test_expect_success \
+    'corruption #0 in delta base reference of first delta (OBJ_OFS_DELTA)' \
     'create_new_pack --delta-base-offset &&
      git prune-packed &&
-     do_corrupt_object $blob_2 2 &&
+     do_corrupt_object $blob_2 2 < /dev/zero &&
      git cat-file blob $blob_1 > /dev/null &&
      test_must_fail git cat-file blob $blob_2 > /dev/null &&
      test_must_fail git cat-file blob $blob_3 > /dev/null'
 
 test_expect_success \
-    '... and a redundant pack allows for full recovery too' \
+    '... but having a loose copy allows for full recovery' \
     'mv ${pack}.idx tmp &&
+     git hash-object -t blob -w file_2 &&
+     mv tmp ${pack}.idx &&
+     git cat-file blob $blob_1 > /dev/null &&
+     git cat-file blob $blob_2 > /dev/null &&
+     git cat-file blob $blob_3 > /dev/null'
+
+test_expect_success \
+    '... and then a repack "clears" the corruption' \
+    'do_repack --delta-base-offset &&
+     git prune-packed &&
+     git verify-pack ${pack}.pack &&
+     git cat-file blob $blob_1 > /dev/null &&
+     git cat-file blob $blob_2 > /dev/null &&
+     git cat-file blob $blob_3 > /dev/null'
+
+test_expect_success \
+    'corruption #1 in delta base reference of first delta (OBJ_OFS_DELTA)' \
+    'create_new_pack --delta-base-offset &&
+     git prune-packed &&
+     printf "\001" | do_corrupt_object $blob_2 2 &&
+     git cat-file blob $blob_1 > /dev/null &&
+     test_must_fail git cat-file blob $blob_2 > /dev/null &&
+     test_must_fail git cat-file blob $blob_3 > /dev/null'
+
+test_expect_success \
+    '... but having a loose copy allows for full recovery' \
+    'mv ${pack}.idx tmp &&
+     git hash-object -t blob -w file_2 &&
+     mv tmp ${pack}.idx &&
+     git cat-file blob $blob_1 > /dev/null &&
+     git cat-file blob $blob_2 > /dev/null &&
+     git cat-file blob $blob_3 > /dev/null'
+
+test_expect_success \
+    '... and then a repack "clears" the corruption' \
+    'do_repack --delta-base-offset &&
+     git prune-packed &&
+     git verify-pack ${pack}.pack &&
+     git cat-file blob $blob_1 > /dev/null &&
+     git cat-file blob $blob_2 > /dev/null &&
+     git cat-file blob $blob_3 > /dev/null'
+
+test_expect_success \
+    '... and a redundant pack allows for full recovery too' \
+    'do_corrupt_object $blob_2 2 < /dev/zero &&
+     git cat-file blob $blob_1 > /dev/null &&
+     test_must_fail git cat-file blob $blob_2 > /dev/null &&
+     test_must_fail git cat-file blob $blob_3 > /dev/null &&
+     mv ${pack}.idx tmp &&
      git hash-object -t blob -w file_1 &&
      git hash-object -t blob -w file_2 &&
      printf "$blob_1\n$blob_2\n" | git pack-objects .git/objects/pack/pack &&