Fix ancestor filter to support Docker-compatible substring matching

- Remove redundant exact match checks in ancestor filter implementations
- Add comprehensive test coverage for both prefix and non-prefix substring matching
- Fix missing output verification in ID filter test
- Improve test reliability with proper length checks and consistent flags
- Remove unnecessary length check to ensure tests fail properly if image ID is too short
- Add -q and --no-trunc flags for consistent test output format
- Focus test on substring ID matching specifically (not image names)
- Restore image name matching functionality for existing tests
- Keep substring ID matching for Docker compatibility
- Ensure both regex matching and substring ID matching work together

The ancestor filter now supports both:
1. Image name matching (existing functionality)
2. Substring ID matching (new Docker compatibility feature)

Fixes: #26623
Signed-off-by: shiavm006 <[email protected]>

Author: shiavm006

pkg/domain/filters/containers.go

@@ -107,8 +107,13 @@ func GenerateContainerFilterFuncs(filter string, filterValues []string, r *libpo
 					imageTag = tag
 				}
 
-				if (rootfsImageID == filterValue) ||
-					util.StringMatchRegexSlice(rootfsImageName, filterValues) ||
+				// Check for substring match on image ID (Docker compatibility)
+				if strings.Contains(rootfsImageID, filterValue) {
+					return true
+				}
+
+				// Check for regex match (advanced use cases)
+				if util.StringMatchRegexSlice(rootfsImageName, filterValues) ||
 					(util.StringMatchRegexSlice(imageNameWithoutTag, filterValues) && imageTag == "latest") {
 					return true
 				}
@@ -363,8 +368,13 @@ func GenerateExternalContainerFilterFuncs(filter string, filterValues []string,
 					imageTag = tag
 				}
 
-				if (listContainer.ImageID == filterValue) ||
-					util.StringMatchRegexSlice(listContainer.Image, filterValues) ||
+				// Check for substring match on image ID (Docker compatibility)
+				if strings.Contains(listContainer.ImageID, filterValue) {
+					return true
+				}
+
+				// Check for regex match (advanced use cases)
+				if util.StringMatchRegexSlice(listContainer.Image, filterValues) ||
 					(util.StringMatchRegexSlice(imageNameWithoutTag, filterValues) && imageTag == "latest") {
 					return true
 				}

test/e2e/ps_test.go

@@ -334,25 +334,38 @@ var _ = Describe("Podman ps", func() {
 		Expect(result.OutputToString()).To(Equal(""))
 	})
 
-	It("podman ps id filter flag", func() {
-		_, ec, fullCid := podmanTest.RunLsContainer("")
+	It("podman ps ancestor filter with substring matching (Docker compatibility)", func() {
+		// Create a container to test with
+		_, ec, cid := podmanTest.RunLsContainer("test1")
 		Expect(ec).To(Equal(0))
 
-		result := podmanTest.Podman([]string{"ps", "-a", "--filter", fmt.Sprintf("id=%s", fullCid)})
-		result.WaitWithDefaultTimeout()
-		Expect(result).Should(ExitCleanly())
+		// Get the full image ID to test substring matching
+		inspect := podmanTest.PodmanExitCleanly("inspect", cid, "--format", "{{.Image}}")
+		fullImageID := inspect.OutputToString()
+
+		// Test with prefix substring of image ID (Docker compatibility, new functionality)
+		imageIDPrefix := fullImageID[:12]
+		result := podmanTest.PodmanExitCleanly("ps", "-q", "--no-trunc", "-a", "--filter", "ancestor="+imageIDPrefix)
+		Expect(result.OutputToString()).To(Equal(cid))
+
+		// Test with non-prefix substring of image ID (Docker compatibility)
+		imageIDSubstr := fullImageID[4:16]
+		result = podmanTest.PodmanExitCleanly("ps", "-q", "--no-trunc", "-a", "--filter", "ancestor="+imageIDSubstr)
+		Expect(result.OutputToString()).To(Equal(cid))
+
+		// Test with non-existent substring (should not match)
+		result = podmanTest.PodmanExitCleanly("ps", "-q", "--no-trunc", "-a", "--filter", "ancestor=nonexistent")
+		Expect(result.OutputToString()).To(Equal(""))
 	})
 
 	It("podman ps id filter flag", func() {
-		session := podmanTest.RunTopContainer("")
-		session.WaitWithDefaultTimeout()
-		Expect(session).Should(ExitCleanly())
-		fullCid := session.OutputToString()
+		_, ec, fullCid := podmanTest.RunLsContainer("")
+		Expect(ec).To(Equal(0))
 
-		result := podmanTest.Podman([]string{"ps", "-aq", "--no-trunc", "--filter", "status=running"})
+		result := podmanTest.Podman([]string{"ps", "-aq", "--no-trunc", "--filter", fmt.Sprintf("id=%s", fullCid)})
 		result.WaitWithDefaultTimeout()
 		Expect(result).Should(ExitCleanly())
-		Expect(result.OutputToStringArray()[0]).To(Equal(fullCid))
+		Expect(result.OutputToString()).To(Equal(fullCid))
 	})
 
 	It("podman ps multiple filters", func() {
@@ -1033,4 +1046,5 @@ var _ = Describe("Podman ps", func() {
 		Expect(output).To(HaveLen(1))
 		Expect(output).Should(ContainElement(ContainSubstring("late")))
 	})
+
 })